Recurrent implantation failure (RIF) refers to the repeated failures of embryo implantation during assisted reproductive technology and half of them remain unexplained (uRIF). Evidence has proven the association between uRIF and immune dysregulation related with natural killer (NK) cells. The aim of this study was to explore the expression of cytotoxic granules, activation and inhibitory receptors within NK cell subsets in both peripheral blood (pbNK) and uterine (uNK) samples during the embryo implantation phase of the menstrual cycle in women with uRIF and live birth (LB). 25 pregnant women who achieved live birth (LB group) and 13 patients with uRIF (uRIF group) were recruited. The expression of ILT2, NKp46, NKp44, NKp30, NKG2D, KIR2DL2/S2/L3, as well as intracellular cytotoxicity granules (perforin and granzyme B) on pbNK and uNK subsets were assessed by flow cytometry. Compared to LB group, the expression of ILT2 receptor on CD56dimCD16bright uNK, NKG2D receptors on CD56dimCD16dim and CD56dimCD16bright uNK were significantly lower in uRIF patients, while the expression of NKp46 receptor on both CD56dimCD16+ pbNK and CD56dimCD16bright uNK subsets were significantly higher in uRIF patients. However, there were no significant difference of perforin and Granzyme B expression in pbNK or uNK cells or their subsets between uRIF and LB groups. The altered expression of ILT2, NKG2D and NKp46 receptors on pbNK and uNK cell subsets might imply the associations between the abnormally expressed activation and inhibitory receptors in NK cell subsets and embryo implantation failure.

Abstract Adrenal chromaffin cells are key effectors of the sympathoadrenal response and play a central role in the organism’s adaptation to environmental and physiological challenges. While cholinergic and pituitary adenylate cyclase-activating polypeptide (PACAP)-dependent mechanisms have long been recognized as major regulators of catecholamine secretion, increasing evidence indicates that connexin-mediated gap junctional communication provides an additional and highly dynamic level of control. Whether early-life experience modifies the adult capacity of chromaffin-cell networks to undergo stress-induced connexin remodeling remains unclear. Here, we examined adrenal medullary connexin expression in adult rats exposed to neonatal maternal separation (MS; 3 h daily, postnatal days 2-15) and later challenged with an 8-day unpredictable mild stress (UMS) protocol. Under basal adult conditions, MS did not produce an overt change in adrenal medullary Cx36 or Cx43 immunoreactivity relative to animal-facility-reared controls. In contrast, UMS increased connexin immunoreactivity in the adrenal medulla, and this response was amplified in animals with a history of MS. MS+UMS animals also displayed enhanced corticosterone responses to acute restraint stress. These findings suggest that neonatal MS does not impose a constitutively altered adult chromaffin-cell phenotype, but instead primes the future stress responsiveness of adrenal medullary connexin remodeling. We propose that chromaffin-cell gap junctions represent a substrate sensitive to stress history, through which developmental experience may influence sympathoadrenal and endocrine adaptation in adulthood.

Adrenal chromaffin cells are key effectors of the sympathoadrenal response and play a central role in physiological adaptation to stress. While acetylcholine and pituitary ad-enylate cyclase-activating polypeptide (PACAP) are recognized regulators of catechol-amine secretion, connexin-mediated gap junctional communication provides an addi-tional mechanism for coordinating chromaffin-cell activity. Whether early-life experience influences the capacity of chromaffin-cell networks to undergo stress-induced remodeling remains unknown. To address this question, we examined connexin 36 (Cx36) and connexin 43 (Cx43) expression in the adrenal medulla of adult rats exposed to neonatal maternal separation (MS; 3 h daily, postnatal days 2–15) and subsequently challenged with an 8-day unpredictable mild stress (UMS) protocol. Under basal adult conditions, MS did not alter adrenal medullary Cx36 or Cx43 immunoreactivity relative to ani-mal-facility-reared controls. In contrast, UMS increased connexin immunoreactivity, and this response was significantly enhanced in animals with a history of MS. MS+UMS animals also displayed augmented corticosterone responses to acute restraint stress, particularly in females. These findings indicate that neonatal maternal separation does not produce a constitutively altered adult chromaffin-cell phenotype but modifies the mag-nitude of subsequent stress-induced adrenal remodeling.

We have discovered a highly specialized innervation of the forebrain by pituitary adenylate cyclase-activating polypeptide (PACAP) immunohistochemistry originating from the brain stem that uses glutamate, acetylcholine, and PACAP, and other peptides as neurotransmitters. The parent neurons of the axons are in the Kölliker-Fuse nucleus, and their terminals form calyx-like multirelease-site synapses in the rodent forebrain extended amygdala similar to the calyx of Held in the auditory brain stem. The latter is a giant, excitatory, cup-like axo-somatic high-fidelity synapse. The PACAP-positive terminals also form enveloping axo-somatic specialization with mixed glutamatergic and cholinergic molecular identities, co-expressing vesicular glutamate transporter 1 (VGluT1), VGluT2, vesicular acetylcholine transport (VAChT), and the neuropeptides PACAP, calcitonin gene-related peptide, and neurotensin, together with calretinin in the presynaptic compartment. We identified a distinct neuronal subpopulation in the pontine Kölliker-Fuse region of the parabrachial complex that gives rise to these calyceal terminals, which engulf Protein kinase C delta (PKCδ+) / Glutamate delta receptor 1 (GluD1+) somata in the capsular central amygdala and oval bed nucleus of the stria terminalis. Strikingly, GluD1 immunolabeling is concentrated at axo-somatic contact zones apposed to VAChT+ presynaptic vesicle cluster zones but is absent from postsynaptic densities of conventional type I synapses within the same terminals. The results demonstrate a previously unrecognized multimodal calyx-like synapse in the forebrain, with parallel fast ionotropic and modulatory peptidergic neurotransmission mechanisms, which is a substrate for high-fidelity signal transmission within viscerosensory-emotional circuits.

Parkinson’s disease (PD)-associated pain, linked to locus coeruleus noradrenergic (LC-NE) degeneration, involves spinal dorsal horn (SDH) nociceptive dysregulation. Using a unilateral 6-OHDA rat PD model combined with DSP-4-induced NE depletion, this study investigated the potential linkage between α2 adrenergic receptor dysfunction and Cav2.2 channel dysregulation in pain pathogenesis. 6-OHDA-induced rats exhibited mechanical/thermal hypersensitivity, exacerbated by DSP-4 co-administration, alongside SDH neuronal hyperactivity (c-FOS), gliosis (GFAP + astrocytes, IBA1 + microglia), inflammatory cytokine elevation, and Cav2.2 upregulation. Clonidine (α2 agonist) concomitantly restored spinal NE levels, reversed nociceptive thresholds, suppressed glial activation, normalized glutamate/GABA imbalance, and downregulated Cav2.2 expression. Notably, Ω-conotoxin GVIA (Cav2.2 antagonist) similarly produced alleviated hypersensitivity, attenuated neuroinflammation, and rebalanced excitatory-inhibitory synaptic transmission. LC-NE degeneration exacerbates PD pain through α2 receptor–associated Cav2.2 hyperactivity in the SDH, potentially driving neuro-glial crosstalk, excitatory-inhibitory dysregulation, and inflammatory signaling.

The calyx of Held, a giant excitatory cup-like axo-somatic synapse, has been historically described exclusively in the auditory brainstem. Here, using PACAP immunohistochemistry combined with confocal and tomographic electron microscopy, we report the discovery of a morphologically similar calyx-like synapse in the extended amygdala of rodents, exhibiting unique neurochemical features. This previously unrecognized structure forms massive axo-somatic terminals with mixed glutamatergic and cholinergic identities, co-expressing VGluT1, VGluT2, VAChT, and the neuropeptides PACAP, CGRP, and neurotensin, along with calretinin in the presynaptic compartment. The postsynaptic targets are a distinct subset of PKCδ-expressing neurons that co-express the synaptic adhesion molecule GluD1. Strikingly, GluD1 immunolabeling is concentrated specifically at axo-somatic contact sites apposed to VAChT+ calyceal terminals, but absent at PSD of conventional type I synapse, suggesting a specialized molecular architecture for calyceal synapse. Our findings reveal a previously unknown calyx-like synapse in the forebrain, exhibiting a unique convergence of fast and modulatory transmission with implications for transmission fidelity within emotional-viscerosensory circuits. Significance Statement Fast and reliable excitatory transmission is essential for neural circuits that govern rapid sensory processing. Until now, the calyx of Held synapse was the only known giant axo-somatic glutamatergic terminal in the mammalian brain. Here, we identify a previously unrecognized calyx-like synapse in the extended amygdala, a key center for emotional and autonomic integration. This massive, multimodal synapse combines glutamatergic, cholinergic, and peptidergic transmission and targets a distinct subset of PKCδ neurons. Its molecular composition, including VGLUT1/2, VAChT, PACAP, and GluD1, suggests a unique structural and functional specialization. This discovery broadens our understanding of synaptic diversity and reveals a novel anatomical substrate for high-fidelity communication in emotional-viscerosensory circuits. ### Competing Interest Statement The authors have declared no competing interest.

Kisspeptinergic signaling is well-established as crucial for the regulation of reproduction, but its potential broader role in brain function is less understood. This study investigates the distribution and chemotyping of kisspeptin-expressing neurons within the mouse brain. RNAscope single, dual, and multiplex in situ hybridization methods were used to assess kisspeptin mRNA (Kiss1) expression and its co-expression with other neuropeptides, excitatory and inhibitory neurotransmitter markers, and sex steroid receptors in wild-type intact and gonadectomized young adult mice. Seven distinct kisspeptin neuronal chemotypes were characterized, including two novel kisspeptin-expressing groups described for the first time, that is, the Kiss1 population in the ventral premammillary nucleus and the nucleus of the solitary tract. Kiss1 mRNA was also observed to localize in both somatic and dendritic compartments of hypothalamic neurons. High androgen receptor expression and changes in medial amygdala and septo-hypothalamic Kiss1 expression following GDX in males, but not in females, suggest a role for androgen receptors in regulating kisspeptin signaling. This study provides a detailed chemoanatomical map of kisspeptin-expressing neurons, highlighting their potential functional diversity. The discovery of a new kisspeptin-expressing group and gonadectomy-induced changes in Kiss1 expression patterns suggest broader roles for kisspeptin in brain functions beyond those of reproduction.

Kisspeptin (KP) signaling in the brain is defined by the anatomical distribution of KP-producing neurons, their fibers, receptors, and connectivity. Technological advances have prompted a re-evaluation of these chemoanatomical aspects, originally studied in the early years after the discovery of KP and its receptor Kiss1r. Previously, we characterized (Hernández et al. bioRxiv 2024) seven KP neuronal populations in the mouse brain at the mRNA level, including two novel populations, and examined their response to gonadectomy. In this study, we mapped KP fiber distribution in rats and mice using immunohistochemistry under intact as well as short- and long-term post-gonadectomy conditions. Kiss1r mRNA expression was examined via RNAscope, in relation to vesicular GABA transporter (Slc32a1) in whole mouse brain, and to KP and vesicular glutamate transporter 2 (Slc17a6), Kiss1, and Slc32a1 in hypothalamic RP3V and arcuate regions. We identified KP fibers in 118 brain regions, primarily in extra-hypothalamic areas associated with sensorial processing and behavioral state control. KP-immunoreactive fiber density and distribution were largely unchanged by gonadectomy. Kiss1r was expressed prominently in sensorial and state control regions such as the septal nuclei, the suprachiasmatic nucleus, locus coeruleus, hippocampal layers, thalamic nuclei, and cerebellar structures. Co-expression of Kiss1r and Kiss1 was observed in hypothalamic neurons, suggesting both autocrine and paracrine KP signaling mechanisms. These findings enhance our understanding of KP signaling beyond reproductive functions, particularly in sensorial processing and behavioral state regulation. This study opens new avenues for investigating KP's role in controlling complex physiological processes, including those unrelated to reproduction.

The calyx of Held is a giant axo-somatic synapse classically confined to the auditory brainstem. We recently identified morphologically similar calyx-like terminals in the extended amygdala (EA) that arise from the ventrolateral parabrachial complex and co-express PACAP, CGRP, VAChT, VGluT1, and VGluT2, targeting PKCδ+/GluD1+ EA neurons. Here, we asked whether this parabrachial–EA pathway participates in compensation during acute hypotension. In rats given hydralazine (10 mg/kg, i.p.), we quantified Fos protein during an early phase (60 min) and a late phase (120 min). Early after hypotension, Fos surged in a discrete subpopulation of the parabrachial Kölliker–Fuse (KF) region and in the EA, whereas magnocellular neurons of the supraoptic and paraventricular nuclei (SON/PVN) remained largely silent. By 120 min, magnocellular SON/PVN neurons were robustly Fos-positive. Confocal immunohistochemistry showed that most Fos+ PKCδ+/GluD1+ EA neurons were encircled by PACAP+ perisomatic terminals (80.8%), of which the majority co-expressed VGluT1 (88.1%). RNAscope in situ hybridization further identified a selective KF population co-expressing Adcyap1 (PACAP) and Slc17a7 (VGluT1) that became fos-positive during the early phase. Together, these data suggest that a KF PACAP+/VGluT1+ projection forms calyceal terminals around PKCδ+/GluD1+ EA neurons, providing a high-fidelity route for rapid autonomic rebound to falling blood pressure, while slower endocrine support is subsequently recruited via neurohormone-magnocellular activation. This work links multimodal parabrachial output to temporally layered autonomic–neuroendocrine control.

The arginine vasopressin (AVP)-magnocellular neurosecretory system (AVPMNS) in the hypothalamus plays a critical role in homeostatic regulation as well as in allostatic motivational behaviors. However, it remains unclear whether adult neurogenesis exists in the AVPMNS. By using immunoreaction against AVP, neurophysin II, glial fibrillar acidic protein (GFAP), cell division marker (Ki67), migrating neuroblast markers (doublecortin, DCX), microglial marker (Ionized calcium binding adaptor molecule 1, Iba1), and 5′-bromo-2′-deoxyuridine (BrdU), we report morphological evidence that low-rate neurogenesis and migration occur in adult AVPMNS in the rat hypothalamus. Tangential AVP/GFAP migration routes and AVP/DCX neuronal chains as well as ascending AVP axonal scaffolds were observed. Chronic water deprivation significantly increased the BrdU+ nuclei within both the supraaoptic (SON) and paraventricular (PVN) nuclei. These findings raise new questions about AVPMNS’s potential hormonal role for brain physiological adaptation across the lifespan, with possible involvement in coping with homeostatic adversities.

BACKGROUND:Kisspeptinergic signaling is well-established as crucial for regulation of reproduction, but its potential broader role in brain function is less understood. This study investigates the distribution and chemotyping of kisspeptin-expressing neurons within the mouse brain. METHODS:RNAscope singleplex, duplex and multiplex in situ hybridization methods were used to assess kisspeptin mRNA (Kiss1) expression and its co-expression with other neuropeptides, excitatory and inhibitory neurotransmitter markers, and sex steroid receptors in intact and gonadectomized young adult mice. RESULTS:Seven distinct kisspeptin neuronal chemotypes were characterized, including within two novel Kiss1-expressing groups described here for the first time: the ventral premammillary nucleus, and the nucleus of the solitary tract. Kiss1 mRNA was also localized in the soma, and within the dendritic compartment, of hypothalamic neurons. Altered Kiss1 expression following gonadectomy suggests a previously unappreciated role for androgen receptors in regulating kisspeptin signaling. CONCLUSION:This study provides a detailed chemoanatomical map of kisspeptin-expressing neurons in the brain, highlighting their potential functional diversity. The discovery of new kisspeptin-expressing neuronal populations, and gonadectomy-induced changes in Kiss1 expression patterns, provide a basis for further exploration of non-endocrine roles for kisspeptin in brain function.

Comprehensive chromosomal status of blastocyst from women with polycystic ovary syndrome (PCOS) was limited. This study aimed to identify possible differences in the preimplantation blastocyst chromosome aberrations between PCOS women and controls receiving preimplantation genetic testing (PGT). This was a multi-center retrospective cohort study including a total of 707 blastocysts from 147 PCOS women and 3006 blastocysts from 821 control women receiving PGT between 2015 and 2021. Embryonic chromosomal aberration spectrums were compared between PCOS and controls. Mixed effects generalized linear model was conducted to explore possible influence of PCOS-related endocrinological disorders on embryonic chromosomal abnormalities. Blastocysts from PCOS demonstrated significantly lower aneuploidy rate (15.2

STUDY QUESTION Can blastocyst aneuploidy be predicted for patients with previous aneuploid pregnancy loss (PAPL) and receiving preimplantation genetic testing for aneuploidy (PGT-A)? SUMMARY ANSWER Multivariable logistic regression models were established to predict high risk of blastocyst aneuploidy using four identified factors, presenting good predictive performance. WHAT IS KNOWN ALREADY Aneuploidy is the most common embryonic chromosomal abnormality leading to pregnancy loss. Several studies have demonstrated a higher embryo aneuploidy rate in patients with PAPL, which has suggested that PGT-A should have benefits in PAPL patients intending to improve their pregnancy outcomes. However, recent studies have failed to demonstrate the efficacy of PGT-A for PAPL patients. One possible way to improve the efficacy is to predict the risk of blastocyst aneuploidy risk in order to identify the specific PAPL population who may benefit from PGT-A. STUDY DESIGN, SIZE, DURATION We conducted a multicenter retrospective cohort study based on data analysis of 1119 patients receiving PGT-A in three reproductive medical centers of university affiliated teaching hospitals during January 2014 to June 2020. Acohort of 550 patients who had one to three PAPL(s) were included in the PAPL group. In addition, 569 patients with monogenic diseaseswithout pregnancy loss were taken as the non-PAPL group. PARTICIPANTS/MATERIALS, SETTING, METHODS PGT-A was conducted using single nucleotide polymorphism microarrays and next-generation sequencing. Aneuploidy rates in Day 5 blastocysts of each patient were calculated and high-risk aneuploidy was definedas a rate of ≥50%. Candidate risk factors for high-risk aneuploidy were selected using the Akaike information criterion andwere subsequently included in multivariable logistic regression models. Overall predictive accuracy was assessed using the confusionmatrix, discrimination by area under the receiver operating characteristic curve (AUC), and calibration by plotting the predictedprobabilities versus the observed probabilities. Statistical significance was set at P < 0.05. MAIN RESULTS AND THE ROLE OF CHANCE Blastocyst aneuploidy rates were 30 ± 25% and 21 ± 19% for PAPL and non-PAPL groups, respectively. Maternal age (odds ratio (OR) = 1.31, 95% CI 1.24-1.39, P < 0.001), number of PAPLs (OR = 1.40, 95% CI 1.05-1.86, P = 0.02), estradiol level on the ovulation trigger day (OR = 0.47, 95% CI 0.30-0.73, P < 0.001), and blastocyst formation rate (OR = 0.13, 95% CI 0.03-0.50, P = 0.003) were associated with high-risk of blastocyst aneuploidy. The predictive model based on the above four variables yielded AUCs of 0.80 using the training dataset and 0.83 using the test dataset, with average and maximal discrepancies of 2.89% and 12.76% for the training dataset, and 0.98% and 5.49% for the test dataset, respectively. LIMITATIONS, REASONS FOR CAUTION Our conclusions might not be compatible with those having fewer than four biopsied blastocysts and diminished ovarian reserves, since all of the included patients had four or more biopsied blastocysts and had exhibited good ovarian reserves. WIDER IMPLICATIONS OF THE FINDINGS The developed predictive model is critical for counseling PAPL patients before PGT-A byconsidering maternal age, number of PAPLs, estradiol levels on the ovulation trigger day, and the blastocyst formation rate. This prediction model achieves good risk stratification and so may be useful for identifying PAPL patients who may have higher risk of blastocyst aneuploidy and can therefore acquire better pregnancy outcomes by PGT-A. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the National Natural Science Foundation of China under Grant (81871159). No competing interest existed in the study. TRIAL REGISTRATION NUMBER N/A.

Journal of NeuroendocrinologyVolume 35, Issue 11 e13345 EDITORIAL Advances in peptide modulation in systems physiology Lee E. Eiden, Lee E. Eiden orcid.org/0000-0001-7524-944X Section on Molecular Neuroscience, National Institute of Mental Health, NIH, Bethesda, Maryland, USA Contribution: Writing - original draft, Writing - review & editingSearch for more papers by this authorDavid Grattan, David Grattan orcid.org/0000-0001-5606-2559 Centre for Neuroendocrinology, Division of Health Sciences, University of Otago, Dunedin, New Zealand Contribution: Conceptualization, Writing - original draft, Writing - review & editingSearch for more papers by this authorXiao-Dong Wang, Xiao-Dong Wang orcid.org/0000-0001-7730-3710 School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China Contribution: Conceptualization, Writing - original draft, Writing - review & editingSearch for more papers by this authorLimei Zhang, Corresponding Author Limei Zhang [email protected] orcid.org/0000-0002-7422-5136 Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico Correspondence Limei Zhang, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico. Email: [email protected] Contribution: Conceptualization, Writing - original draft, Writing - review & editingSearch for more papers by this author Lee E. Eiden, Lee E. Eiden orcid.org/0000-0001-7524-944X Section on Molecular Neuroscience, National Institute of Mental Health, NIH, Bethesda, Maryland, USA Contribution: Writing - original draft, Writing - review & editingSearch for more papers by this authorDavid Grattan, David Grattan orcid.org/0000-0001-5606-2559 Centre for Neuroendocrinology, Division of Health Sciences, University of Otago, Dunedin, New Zealand Contribution: Conceptualization, Writing - original draft, Writing - review & editingSearch for more papers by this authorXiao-Dong Wang, Xiao-Dong Wang orcid.org/0000-0001-7730-3710 School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China Contribution: Conceptualization, Writing - original draft, Writing - review & editingSearch for more papers by this authorLimei Zhang, Corresponding Author Limei Zhang [email protected] orcid.org/0000-0002-7422-5136 Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico Correspondence Limei Zhang, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico. Email: [email protected] Contribution: Conceptualization, Writing - original draft, Writing - review & editingSearch for more papers by this author First published: 03 October 2023 https://doi.org/10.1111/jne.13345 Special Issue of papers from the 24th International Symposium on Regulatory Peptides (RegPep24 World Conference), 1st–5th August 2022, University of Stirling, Scotland, UK. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Open Research PEER REVIEW The peer review history for this article is available at https://www.webofscience.com/api/gateway/wos/peer-review/10.1111/jne.13345. DATA AVAILABILITY STATEMENT Data sharing is not applicable to this article as no new data were created or analyzed in this study. REFERENCES 1Hernandez-Perez OR, Hernández VS, Zetter MA, Eiden LE, Zhang L. Nucleus of the lateral olfactory tract: a hub linking the water homeostasis-associated supraoptic nucleus-arginine vasopressin circuit and neocortical regions to promote social behavior under osmotic challenge. J Neuroendocrinol. 2022;223:e13202. 2Peles G, Swaminathan A, Levkowitz G. Glucocorticoid-sensitive period of corticotroph development-implications for mechanisms of early life stress. J Neuroendocrinol. 2022;e13229. 3Sabban EL, Serova L, Nahvi RJ, Liu X. Potential benefits of intranasal neuropeptide Y include sustained extinction of fear memory. J Neuroendocrinol. 2023;223:e13279. 4Chen X, Coffman BL, Brindley RL, et al. Phospholipase C-epsilon defines a PACAP-stimulated pathway for secretion in the chromaffin cell. J Neuroendocrinol. 2023;223:e13255. 5Bakalar D, Gavrilova O, Jiang SZ, et al. Constitutive and conditional deletion reveals distinct phenotypes driven by developmental versus neurotransmitter actions of the neuropeptide PACAP. J Neuroendocrinol. 2023;223:e13286. 6Kozlova EV, Bishay AE, Denys ME, et al. Gene deletion of the PACAP/VIP receptor, VPAC2R, alters glycemic responses during metabolic and psychogenic stress in adult female mice. J Neuroendocrinol. 2023;223. 7Paes-Leme B, Monteiro LRN, Gholami K, et al. Fasting increases circulating angiotensin levels and brain Agtr1a expression in male rats. J Neuroendocrinol. 2023;223:e13334. 8Chen D, Hagen SJ, Boyce M, Zhao CM. Neuroendocrine mechanism of gastric acid secretion: historical perspectives and recent developments in physiology and pharmacology. J Neuroendocrinol. 2023; 223:e13305. 9Chen D, Rehfeld JF, Watts AG, Rorsman P, Gundlach AL. History of key regulatory peptide systems and perspectives for future research. J Neuroendocrinol. 2023;223:e13251. Volume35, Issue11Special Issue: Special Issue of articles from the 24th International Symposium on Regulatory Peptides (RegPep24), University of Stirling, Scotland, UK, August 2022November 2023e13345 ReferencesRelatedInformation

BACKGROUND:The mechanism of pain symptoms in Parkinson's disease (PD) is unclear. Norepinephrine (NE) regulates neuropathic pain through ascending and descending pathways. However, the loss of NE neurons in the brain of patients with PD is obvious, it is speculated that NE is involved in the occurrence of PD pain symptoms.AIMS:To investigate the effect of NE on the activation of brain cells through adrenergic α2 receptor, so as to regulate the nociception threshold in a 6-OHDA-induced animal model of PD.METHODS:PD rat model was established by 6-OHDA injection (6-OHDA group). DSP-4 (or anti-DBH-saporin) was used to reduce the NE level of the PD rat brain. The heat sensitivity threshold (HST) and pressure withdrawal threshold (PWT) were measured. Tyrosine hydroxylase and NE in rat brains were detected by Elisa. The percentage of GFAP-positive cells in the prefrontal cortex, cingulate gyrus and striatum of rats was detected by immunohistochemistry and immunofluorescence. GFAP protein was semiquantified by method of western blot. Then yohimbine and guanfacine were used to increase the NE level in PD rats, and the above experimental changes were observed after drug application.RESULTS:The contents of NE in the brain of 6-OHDA-induced PD rats were lower than that of control group. After DSP-4 (or anti-DBH-saporin) injection, PD rats showed the lowest NE level (compared with 6-OHDA group, p ≤ 0.05), and after yohimbine and guanfacine were applied to 6-OHDA group, the contents of NE increased in the prefrontal cortex of rats. The HST and PWT of 6-OHDA group were significantly lower than those of control group, and after DSP-4 (or anti-DBH-saporin) injection, the HST and PWT of rats were lower than those of 6-OHDA group, and after the administration of yohimbine and guanfacine, both HST and PWT were significantly increased. GFAP-positive cells increased in prefrontal cortex and anterior cingulate gyrus of 6-OHDA group rats, and more significantly increased after DSP-4 (or anti-DBH-saporin) injection, and significantly reduced after yohimbine and guanfacine were used.CONCLUSIONS:The change of norepinephrine content can affect the activation of prefrontal and cingulate gyrus glial cells and participate in the regulation of nociception threshold in PD rats. Adrenergic α2 receptor agonist and central presynaptic membrane α2 receptor blocker both affect cell activation and improve hyperalgesia.

Mycobacterium tuberculosis (Mtb) WhiB3 is an iron-sulfur cluster-containing transcription factor belonging to a subclass of the WhiB-Like (Wbl) family that is widely distributed in the phylum Actinobacteria. WhiB3 plays a crucial role in the sur-vival and pathogenesis of Mtb. It binds to the conserved region 4 of the principal sigma factor (& sigma;A 4) in the RNA polymerase holoenzyme to regulate gene expression like other known Wbl proteins in Mtb. However, the structural basis of how WhiB3 coordinates with & sigma;A4 to bind DNA and regulate transcription is unclear. Here we determined crystal structures of the WhiB3:& sigma;A4 complex without and with DNA at 1.5 & ANGS; and 2.45 & ANGS;, respectively, to elucidate how WhiB3 interacts with DNA to regulate gene expression. These structures reveal that the WhiB3:& sigma;A4 complex shares a molecular interface similar to other structurally characterized Wbl proteins and also pos-sesses a subclass-specific Arg-rich DNA-binding motif. We demonstrate that this newly defined Arg-rich motif is required for WhiB3 binding to DNA in vitro and transcriptional regu-lation in Mycobacterium smegmatis. Together, our study pro-vides empirical evidence of how WhiB3 regulates gene expression in Mtb by partnering with & sigma;A4 and engaging with DNA via the subclass-specific structural motif, distinct from the modes of DNA interaction by WhiB1 and WhiB7.

Homeostatic challenges increase the drive for social interaction. The neural activity that prompts this motivation remains poorly understood. Here, we identify direct projections from hypothalamic supraoptic nucleus (SON) to the cortico-amygdalar nucleus of the lateral olfactory tract (NLOT). Dual in situ hybridization (DISH) with probes for PACAP, and VGLUT1, VGLUT2, V1a and V1b revealed a population of vasopressin-receptive PACAPergic neurons in NLOT layer 2 (NLOT2). Water deprivation (48 hours, WD48) increased sociability compared to euhydrated subjects, assessed with the three-chamber social interaction test (3CST). Fos expression immunohistochemistry showed NLOT and its main efferent regions had further increases in rats subjected to WD48+3CST. These regions strongly expressed PAC1 mRNA. Microinjections of AVP into NLOT produced similar changes in sociability to water deprivation, and these were reduced by co-injection of V1a or V1b antagonists along with AVP. We conclude that during challenge to water homeostasis, there is a recruitment of a glutamatergic-multi-peptidergic cooperative circuit that promotes social behavior. Supported by grants UNAM-DGAPA-PAPIIT- PAPIIT-IN216918 & GI200121 & CONACYT-CB-283279 (LZ); MH002386, NIMH, NIH, USA (LEE).

Homeostatic challenges may alter the drive for social interaction. The neural activity that prompts this motivation remains poorly understood. In the present study, we identify direct projections from the hypothalamic supraoptic nucleus to the cortico‐amygdalar nucleus of the lateral olfactory tract (NLOT). Dual in situ hybridization with probes for pituitary adenylate cyclase‐activating polypeptide (PACAP), as well as vesicular glutamate transporter (VGLUT)1, VGLUT2, V1a and V1b, revealed a population of vasopressin‐receptive PACAPergic neurons in NLOT layer 2 (NLOT2). Water deprivation (48 h, WD48) increased sociability compared to euhydrated subjects, as assessed with the three‐chamber social interaction test (3CST). Fos expression immunohistochemistry showed NLOT and its main efferent regions had further increases in rats subjected to WD48 + 3CST. These regions strongly expressed PAC1 mRNA. Microinjections of arginine vasopressin (AVP) into the NLOT produced similar changes in sociability to water deprivation, and these were reduced by co‐injection of V1a or V1b antagonists along with AVP. We conclude that, during challenge to water homeostasis, there is a recruitment of a glutamatergic‐multi‐peptidergic cooperative circuit that promotes social behavior.

Neuropeptides are expressed in cell-specific patterns throughout mammalian brain. Neuropeptide gene expression has been useful for clustering neurons by phenotype, based on single-cell transcriptomics, and for defining specific functional circuits throughout the brain. How neuropeptides function as first messengers in inter-neuronal communication, in cooperation with classical small-molecule amine transmitters (SMATs) is a current topic of systems neurobiology. Questions include how neuropeptides and SMATs cooperate in neurotransmission at the molecular, cellular and circuit levels; whether neuropeptides and SMATs always co-exist in neurons; where neuropeptides and SMATs are stored in the neuron, released from the neuron and acting, and at which receptors, after release; and how neuropeptides affect 'classical' transmitter function, both directly upon co-release, and indirectly, via long-term regulation of gene transcription and neuronal plasticity. Here, we review an extensive body of data about the distribution of neuropeptides and their receptors, their actions after neuronal release, and their function based on pharmacological and genetic loss- and gain-of-function experiments, that addresses these questions, fundamental to understanding brain function, and development of neuropeptide-based, and potentially combinatorial peptide/SMAT-based, neurotherapeutics.