Little is known about the venom of Salticidae spiders, so here, we look for venom peptides of the most cosmopolitan spider, Phidippus audax. The isolation, chemical synthesis, and pharmacological characterization of a short peptide from the venom of the spider Phidippus audax (Araneae: Salticidae) was performed by HPLC chromatography, solid-phase peptide synthesis, and electrophysiology on rat dorsal root ganglia neurons, respectively. The unveiled peptide (Paudax1) consists of 22 residues and contains a single disulfide bridge. Paudax1 has paralytic activity against Acheta domesticus. It was synthesized in two N-terminal forms, Phi-Ala and Phi-Trp. . The pharmacology of both homologous peptides was evaluated in primary cultures of rat dorsal root ganglia neurons. Microperfusion of Phi-Ala [10 µM] (n = 6) resulted in a 17 ± 5

This is a narrative review that explores the development of non-implantable vestibular devices designed to address postural instability, particularly in aging populations and patients with vestibular hypofunction. It establishes that balance relies on complex sensory integration and that the functional decline of this system creates a significant medical need. Three principal technological strategies are examined: sensory substitution devices, galvanic vestibular stimulation (GVS), and immersive visual feedback systems. Sensory substitution devices, which convert balance data into auditory, tactile, or electrotactile cues, demonstrate significant promise. Examples like vibrotactile belts provide feedback that reduces postural sway, enhancing stability and patient confidence. Parallel to this, GVS—using electrical currents applied to the mastoids—emerges as a potent non-invasive method to modulate vestibular pathways, improving balance control and even inducing neuroplastic changes, especially with stochastic “noisy” signals. The most recently developed devices include augmented and virtual reality technologies that offer innovative visual feedback, creating enriched rehabilitation environments that accelerate recovery by promoting sensory reweighting and neural adaptation. This review concludes that while implantable prostheses are advancing, non-invasive devices offer versatile, affordable, and complementary solutions for balance restoration. The future success of non-invasive alternatives hinges on developing more sophisticated stimulation protocols that account for the complexity of natural movement and individual patient contexts, expanding therapeutic options for vestibular disorders.

Alcohol consumption significantly impairs postural stability by disrupting vestibular function, increasing the risk of falls. This study investigated the feasibility of using galvanic vestibular stimulation (GVS) to mitigate alcohol-induced postural instability in healthy adults, employing acute alcohol intake as a transient model of vestibular dysfunction. Sixty participants were assigned to groups with or without alcohol consumption (estimated blood alcohol concentration [BAC] 0.06%-0.08%) and randomly received one of three GVS types: random noise (rnGVS), direct current plus random noise (rn-dcGVS), or a sham stimulation (fGVS). Static balance was assessed using a stabilometric platform with eyes closed on an unstable surface. As expected, alcohol consumption significantly worsened stabilometric parameters, resembling vestibular pathological hypofunction. fGVS produced no significant changes, ruling out a placebo effect. Notably, rnGVS significantly improved postural stability in subjects who consumed alcohol, reducing sway velocity, maximal anteroposterior (Max AP), and mediolateral displacements (Max ML) during and immediately after stimulation. In contrast, rn-dcGVS worsened stability in subjects in the no alcohol consuming group with no significant change in the alcohol consuming group. These results demonstrate that rnGVS can effectively attenuate alcohol-induced postural instability in a transient experimental model of vestibular dysfunction and support the use of acute alcohol intake as a controlled model for investigating vestibular modulation.

Cardiovascular modulation in response to movement and gravitational forces can be influenced by vestibular input or peripheral baroreflex mechanisms. Galvanic vestibular stimulation (GVS) is a widely used, noninvasive method for activating neural pathways within the vestibular system, as well as associated pathways such as vestibulo-spinal, oculomotor, and vestibulo-autonomic circuits. Research on vestibulo-autonomic function via GVS has primarily focused on its effects on cardiovascular modulation and sympathetic muscle and nerve activity. However, inconsistencies in GVS application protocols across studies have made it challenging to reach a consensus regarding its effectiveness in modulating the vestibulo-autonomic pathway. Evidence suggests that GVS induces transient autonomic changes by stimulating a neural pathway sensitive to otolith input. This review collates the parameters used in GVS application and examines their effects on autonomic neural pathways by analyzing variations in amplitude, frequency, and electrode montage to understand their impact on autonomic responses, including changes in heart rate (HR), blood pressure (BP), and sympathetic muscle or nerve activity (MSNA). By analyzing stimulation parameters and experimental protocols, we aim to determine their impact on autonomic activation and evaluate their potential for precise autonomic modulation. Finally, based on the evidence generated in populations with neurological disorders and motion sickness, we discuss the potential of GVS as a complementary neuromodulation strategy to treat autonomic dysregulation.

Citation: Soto E and Askwith C (2024) Editorial: ASICs: structure, function, and pharmacology, part II. Front. Physiol. 15:1390239. doi: 10.3389/fphys.2024.1390239

This work discusses the challenges of space exploration, focusing on microgravity-induced physiological changes, particularly those affecting the vestibular system, which significantly alters human performance in space, necessitating effective countermeasures. In microgravity, astronauts experience disorientation and space motion sickness due to changes in vestibular input, leading to symptoms like vertigo and headache. Postflight, astronauts show various neurological changes, similar to symptoms in individuals with vestibular disorders experiencing significant cognitive and perceptual difficulties. Studies have also shown that microgravity affects cortical and sensory responses, altering perception, motor function, and brain connectivity. Galvanic Vestibular Stimulation (GVS) is explored as a countermeasure, using modulated electrical currents to evoke neuronal activity in vestibular end-organs, potentially stabilizing posture and gaze in microgravity. The work proposes that GVS could serve as a non-invasive intervention to help adapt to space environments by enhancing vestibular function and possibly aiding cognitive functions and underscores the need for continued research into the vestibular system’s role in human health and performance during space missions. It highlights the potential of GVS as a promising countermeasure for the challenges posed by microgravity.

Galvanic vestibular stimulation (GVS) helps stabilize subjects when balance and posture are compromised. This work aimed to define the cortical regions that GVS activates in normal subjects. We used functional near-infrared spectroscopy (fNIRS) to test the hypothesis that GVS activates similar cortical areas as a passive movement. We used transcranial current stimulation (cathode in the right mastoid process and anode in the FPz frontopolar point) of bipolar direct current (2 mA), false GVS (sham), vibration (neutral stimulus), and back and forth motion (positive control of vestibular movement) in 18 clinically healthy volunteers. Seventy-two brain scans were performed, applying a crossover-type experimental design. We measured the heart rate, blood pressure, body temperature, head capacitance, and resistance before and after the experiment. The haemodynamic changes of the cerebral cortex were recorded with an arrangement of 26 channels in four regions to perform an ROI-level analysis. The back-and-forth motion produced the most significant oxygenated haemoglobin (HbO2 ) increase. The response was similar for the GVS stimulus on the anterior and posterior parietal and right temporal regions. Sham and vibrational conditions did not produce significant changes ROI-wise. The results indicate that GVS produces a cortical activation coherent with displacement percept.

Balance disorders are highly prevalent worldwide, causing substantial disability with high personal and socioeconomic impact. The prognosis in many of these patients is poor, and rehabilitation programs provide little help in many cases. This medical problem can be addressed using microelectronics by combining the highly successful cochlear implant experience to produce a vestibular prosthesis, using the technical advances in micro gyroscopes and micro accelerometers, which are the electronic equivalents of the semicircular canals (SCC) and the otolithic organs. Reaching this technological milestone fostered the possibility of using these electronic devices to substitute the vestibular function, mainly for visual stability and posture, in case of damage to the vestibular endorgans. The development of implantable and non-implantable devices showed diverse outcomes when considering the integrity of the vestibular pathways, the device parameters (current intensity, impedance, and waveform), and the targeted physiological function (balance and gaze). In this review, we will examine the development and testing of various prototypes of the vestibular implant (VI). The insight raised by examining the state-of-the-art vestibular prosthesis will facilitate the development of new device-development strategies and discuss the feasibility of complex combinations of implantable devices for disorders that directly affect balance and motor performance.

The article shows a theoretical (part 1) improvement in thestabilization of the gaze in galvanic vestibular stimulation.

EDITORIAL article Front. Physiol., 31 January 2022Sec. Membrane Physiology and Membrane Biophysics Volume 13 - 2022 | https://doi.org/10.3389/fphys.2022.831830

Previous works showed that opioid peptides are produced by olivocochlear efferent neurons, while cochlear hair cells express opioid receptors. It has been proposed that opioids protect the auditory system from damage by intense stimulation, although their use for therapeutic or illicit purposes links to hearing impairment. Therefore, it is relevant to study the effect of opioids in the auditory system to define their functional expression and mechanism of action. This study investigated the modulation of the Ca2+ currents by opioid peptides in the rat outer hair cells (OHC) using the whole-cell patch-clamp technique. The influence of agonists of the three opioid receptor subtypes (μ, δ, and κ) was studied. The κ opioid receptor agonist U-50488 inhibits the Ca2+ currents in a partially reversible form. Coincidently, norbinaltorphimine (a κ receptor antagonist) blocked the U-50488 inhibitory effect on the Ca2+ current. The δ and the μ opioid receptor agonists did not significantly affect the Ca2+ currents. These results indicate that the κ opioid receptor activation inhibits the Ca2+ current in OHC, modulating the intracellular Ca2+ concentration when OHCs depolarize. The modulation of the auditory function by opioids constitutes a relevant mechanism with a potential role in the physiopathology of auditory disturbances.

Introducción: las medidas sanitarias de emergencia impuestas para contener el SARS-CoV-2 pueden tener efectos colaterales en la atención de enfermedades cardiovasculares.Los datos mundiales de los países sobre la incidencia de infarto agudo de miocardio con elevación del segmento ST (IAMCEST) durante la pandemia son fundamentales para la política sanitaria futura.Objetivos: nuestro objetivo fue determinar si las medidas sanitarias de emergencia impuestas en Uruguay tuvieron un impacto directo en la calidad de la atención en la reperfusión del IAMCEST.Métodos: realizamos un estudio retrospectivo poblacional de todo el país para determinar la incidencia de reperfusión de IAMCEST (fibrinolíticos e intervención coronaria percutánea, FBL e ICP respectivamente) durante el período sanitario de emergencia.La tasa de incidencia de la reperfusión, el tiempo hasta la reperfusión y la mortalidad asociada se recopilaron de la base de datos del Fondo Nacional de Recursos (organización gubernamental única a cargo de la financiación de la reperfusión del IAMCEST en Uruguay).Estos mismos datos se recuperaron para 2019, 2018 y 2017

The study of cardiovascular function with galvanic vestibular stimulation has provided evidence on the neural structures that are involved in the vestibulo-autonomic reflex. This study determined if the effect on heart rate using galvanic vestibular stimulation persists after provoking a sympathetic response and if this response differs when using unilateral or transmastoid (bilateral) stimulation. We analysed heart rate and heart rate variability using unilateral and transmastoid galvanic vestibular stimulation combined with cardiovascular reflex evoked by postural change in 24 healthy human subjects. Three electrode configurations were selected for unilateral stimulation considering the anatomical location of each semicircular canal. We compared recordings performed in seated and standing positions, and with unilateral and transmastoid stimulation. With subjects seated, a significant transient decrease in heart rate was observed with unilateral stimulation. With transmastoid stimulation, heart rate decreased in both seated and standing positions. Average intervals between normal heartbeats recorded with stimulation resemble parasympathetic cardiac function induced by auricular vagal nerve stimulation. Our results indicate that unilateral stimulation does not eliminate the natural heart rate increase caused by orthostatic hypotension. In contrast, transmastoid stimulation provoked a transient reduction in heart rate, even when subjects were standing. These responses should be considered while performing experiments with galvanic vestibular stimulation and subsequent effects in cardiac regulation mechanisms.

A mathematical model of the formation of output information in a biosensor of angular acceleration is presented. The functional and numerical parameters of the model have been determined by results of experiments made in 2001–2008. A comparison with the mathematical model of J. M. Goldberg and C. Fernandez (1971) describing the change in spike frequency of the primary afferent neuron spikes in response to an angular acceleration of the head as it turns around a vertical axis is carried out.

Our results show that in primary vestibular afferent neurons, activation of the nociceptin/orphanin FQ peptide receptor inhibits the N-type calcium current by a mechanism mediated by G proteins. We propose that calcium current inhibition modulates neurotransmitter release from vestibular afferents, producing a presynaptic modulation of vestibular input to vestibular nuclei, thus contributing to gain control in the vestibular afferent input.

In this work we synthetized seven samples of titania doped with nanoparticles of gadolinium oxide which, previously, were doped with europium at 2 mol%. The doped samples of titania were synthetized using the sol gel method and the nanoparticles of gadolinium oxide were synthetized by the precipitation reaction of precursors of gadolinium nitrate hexahydrate and europium nitrate pentahydrate. All the titania samples were submitted to a thermal treatment at 750 degrees C. Optical properties, such as the absorption, emission, and emission decay times, besides the X-ray diffraction patterns and the Raman spectra were recorded and analysed. The band gap was calculated from the extrapolation of the linear fit in the absorption edge range in the Tauc plot, the electronic transitions of the europium were identified. Finally, due to the high luminescent intensity of the nanoparticles of gadolinium oxide doped with europium, the possible incorporation of these into the matrix of titania, the possibility for exciting these using lower energy (375 nm) and consequently the shift in the band gap; made it possible to propose the material be used for photocatalytic and photonic applications.

Galvanic Vestibular Stimulation(GVS) induce the sensation of movement in subjects in flight simulators and in cosmonauts, creating a cognitive simulation of movement. The system consists of a control unit, a function generator, and a power amplifier. GVS is capable of activating the neurons of the vestibular system and inducing the sensation of movement. When applied in coordination with a flight simulation program GVS modifies the eye movement control responses, electrically activating the vestibular-ocular, vestibule-colic, and vestibule-spinal reflexes. The ultimate goal of this type of stimulation is to generate augmented reality in the pilots during training or potentially also during a flight in microgravity.

Background: Emergency sanitary measures imposed to contain spread and infection of SARS-CoV-2 may have collateral effects on care for cardiovascular disease. Global country data regarding incidence of acute myocardial infarction (STEMI) during the pandemia is critical for future health care policy. Our objective was to determine whether emergency sanitary measures imposed in Uruguay during the pandemia for SARS-CoV-2 had a direct impact on the quality of care for STEMI. Methods: We performed a whole country population based retrospective study to determine the incidence for STEMI reperfusion (fibrinolytics and percutaneous) (FBL and PCI respectively) during the emergency sanitary period. Incidence rate of STEMI reperfusion, time to reperfusion and mortality associated with reperfusion was collected from the National Resources Fund (unique governmental based organization in charge of STEMI reperfusion in Uruguay). This same data was retrieved for 2019, 2018 and 2017. Data was Findings: Number of treated patients for STEMI (PCI and FBL) in Uruguay was lower in 2020 (136 patients) compared to 2019 (180 patients), 2018 (182 patients) and 2017 (174 patients). FBL was performed as unique treatment in 5.1%, 7.2%, 7.7% and 12.1% respectively. Incidence rate for STEMI in Uruguay during the studied period in 2020 was lower with a reduced IRR (0.74, 95%CI: 0.59, 0.91) compared with previous years. Median time to reperfusion was similar (4.10h; range 0.67 – 23.50h) compared to 2019 (3.50h; range 0.50 – 23.50h), 2018 (3.60h; range 0.80 – 22.75h) and 2017 (3.70h; range 0.25 – 23.00h) (p=0.4). Mortality after 15 days was similar in 2017 (8%), 2018 (6%), 2019 (11%) and 2020 (8%). Interpretation: Emergency sanitary measures were associated with a decrease in the incidence for STEMI reperfusion without affecting its time to reperfusion and mortality.Funding Statement: No funding was received.Declaration of Interests: The authors declare not to have any interest conflicts.Ethics Approval Statement: The study was approved by the NRF review board and informed consent was collected from all patients before any reperfusion procedure was performed.