Schizophrenia (SCZ) afflicts around 1% of the world’s population with characteristic symptoms such as hallucinations, delusions, and cognitive disorders. Several experimental studies in the past have indicted brain histaminergic neuronal system involvement in the pathogenesis of psychotic disorders including SCZ. Present study investigates anti-schizophrenic activity using two histamine H3-receptor (H3R)-antagonists/inverse agonists, ciproxifan (3.0 mg/kg, ip) and clobenpropit (15 mg/kg, ip), on some of the established animal model of schizophrenia, for example, amphetamine (AMPH) and dizocilpine (MK-801)-induced hyperactivity, apo-morphine (APO)-induced climbing behavior, scopolamine and MK-801-induced learning and memory deficits and haloperidol-induced catalepsy including determination of acetylcholinesterase (AChE) activity. Results of the present study demonstrate that ciproxifan and clobenpropit were able to control AMPH and MK-801-induced hyperlocomotor activities demonstrated as reduced horizontal activity and reduced number of movements made by rats. Further, there was overall reduction in APO-induced climbing behavior. Learning and memory deficits, as evaluated on elevated plus maze, followed by estimation of brain AChE activity demonstrated positive results with these protypical imidazole H3R-antagonists/inverse agonists.In conclusion, present study demonstrates anti-schizophrenic like activities of ciproxifan and clobenpropit and supports the therapeutic interest of histamine H3R antagonists/inverse agonists to improve symptomatic treatment of psychotic disorders.

We had previously reported decreased serum brain-derived neurotrophic factor (BDNF) levels in depressed patients. In the present study, we tested the hypothesis that antidepressant treatment would normalize serum BDNF levels, at least in a subgroup of patients. Major depressed patients (15 females and 11 males) diagnosed according to DSM-IV criteria and healthy controls (13 females and 13 males) participated in this study. Serum BDNF was assayed with the ELISA method for depressed and remitted patients and the severity of depression was evaluated with the Montgomery-Asberg Depression Rating Scale. An analysis of variance showed that treatment had an effect [F(1, 24) = 4.46, p = 0.045] on the normalization of serum BDNF levels. We also found a correlation between the severity of depression (r = 0.51, p = 0.008), the pretreatment BDNF levels (r = 0.62, p = 0.001) and the difference in serum BDNF levels after antidepressant treatment. These results suggest that antidepressant treatment has a positive effect on serum BDNF levels and support the hypothesis of neurotrophic factor involvement in affective disorders.

Suicide is a major public health problem but the neurobiological factors of risk are poorly understood. Recent studies have mentioned changes in the serotoninergic system and in neuronal plasticity, as well. The present investigation was undertaken to examine whether there is an abnormality in brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) proteins in suicide victims. The effect of diagnosis and drug treatments on the neurotrophins was also assessed. Thirty suicide victims (11 F/19 M) and twenty-four (10 F/14 M) drug-free non-suicide subjects, devoid of psychiatric or neurological disease, were examined. Antemortem diagnoses and toxicological analyses had been performed. The ventral prefrontal cortex (PFC), the hippocampus, and the entorhinal cortex were selected. BDNF and NT-3 levels were assayed either with the Western blot or with the ELISA method. Results indicated a significant decrease in BDNF and NT-3 levels in the hippocampus and PFC (only BDNF) but not in the entorhinal cortex, of suicide victims who were drug-free compared with non-suicide controls. The decrease was observed in all suicide victims, regardless of diagnosis. In drug-treated suicide victims, neurotrophin levels were not significantly different from non-suicide controls. This study supports a role of BDNF and NT-3 neurotrophin, in the pathophysiology of suicidal behavior. Anatomically, this role may implicate the hippocampus and the PFC but not the entorhinal cortex. The absence of change in BDNF and NT-3 levels of drug-treated suicide victims suggests that both neurotrophins are mediators of psychotropic drugs. A better understanding of the neurobiology of suicide could help detect populations at risk.

BACKGROUND:Recent reports have suggested a role for brain-derived neurotrophic factor (BDNF) in psychiatric disorders. Decreased serum BDNF levels have been reported in major depression, but the cause of this decrease has not yet been investigated. The goal of this study was to assess blood BDNF and a platelet activation index, PF4.METHODS:Forty-three drug-free patients (27 female, 16 male) diagnosed with major depression and 35 healthy control subjects (18 female, 17 male) were assessed for plasma, serum, and blood BDNF content. Brain-derived neurotrophic factor and PF4 were assayed with enzyme-linked immunosorbent assay methods, and severity of depression was evaluated with the Montgomery-Asberg Depression Rating Scale.RESULTS:Serum and plasma BDNF levels were decreased in depressed patients compared with control subjects. In whole blood, BDNF levels were unaltered in the depressed subjects compared with control subjects. The serum/blood BDNF ratio was lower in patients with major depression. Increased plasma but not serum PF4 levels were observed in depressed subjects compared with control subjects.CONCLUSIONS:Our results suggest that an alteration of serum or plasma BDNF is not due to the change in blood BDNF but rather is probably related to mechanisms of BDNF release. Secretion of BDNF seems to be independent of platelet reactivity; other mechanisms are therefore probably involved and need to be elucidated.

Background: Abnormalities in cAMP signaling and altered expression of downstream targets such as brain-derived neurotrophic factor (BDNF) have been postulated in patients with bipolar disorder (BD). Methods: The PKA activity and levels of 3H–cAMP binding to PKA R regulatory subunits were measured in lymphoblasts from 10 BD and 10 control subjects. In addition, the possibility that BDNF expression could be altered in these cells has been explored. Results: Results indicate that PKA activity significantly increased (t-test; P<0.01), whereas the 3H–cAMP binding to PKA R subunits decreased in cells from BD (t-test; P<0.02). The presence of 10 μM Sp–cAMP in culture 24 h before cell harvesting induced an increase in enzyme activity and a decrease in 3H–cAMP binding sites (t-test; P<0.01), with a significant difference between BD and controls (t-test; P<0.01). This presence of Sp–cAMP also results in increased BDNF expression (t-test, P<0.01), but neither in resting cells, nor in stimulated cells, was any difference observed in BDNF expression between BD and controls (t-test, NS). Limitations: This study was conducted on a peripheral model cell, whose importance of BDNF is unknown. Conclusion: These data suggest that the upregulation of cAMP signaling observed in BD patients results in the normalization of the BDNF expression. Studies on signal transduction, gene expression and pathologies have implications for development of novel treatments.

Recent findings with animal models have suggested a possible role for brain-derived neurotrophic factor (BDNF) in depression. We have therefore hypothesized that depression could be characterized by low levels of serum BDNF. Major depressed patients (15F+15M) diagnosed according to DSM-IV criteria and healthy controls (15F+15M) participated in the study. Serum BDNF was assayed with the ELISA method and the severity of depression was evaluated with Montgomery–Åsberg-Depression Rating Scale (MADRS). BDNF levels were significantly lower in patients than in controls: 22.6±3 and 26.5±7 ng/ml (t-test=2.7; d.f.=58; P<0.01). They were negatively correlated to the MADRS scores (r=−0.55; P<0.02). Female patients were more depressed and released less BDNF than men. Analysis of covariance (MADRS and gender as independent variable vs. BDNF as dependent variable) indicated that depression severity mainly accounted for the negative correlation. These results suggest that major depression is characterized by low serum BDNF levels and support the hypothesis of neurotrophic factor involvement in affective disorders.

Cyclic AMP-dependent protein kinase (PKA) activity was involved in a number of brain functions such as cognitive process or aging. The measurement of PKA activity is traditionally based on the use of [(32)P]ATP in phosphorylation of specific protein. Recently non-isotopic PKA assays have been developed, but none has been tested on brain homogenates. This work aimed to adapt a fluorimetric method of PKA activity into a novel assay never applied before in brain homogenate, and to characterize the enzyme activity and ratio in hippocampus and cortex from rats of different ages. Optimal conditions of homogenization and enzyme protection were determined. The method was sensitive and reproducible (intra-assay and interassay variation was 5.0% and 9.0%, respectively). In hippocampal cytosol, PKA activity was 27+/-8 and 80+/-9 nmol/min per mg protein in basal and cAMP-stimulated activity, respectively, and accounted for 80% of total cell PKA activity. The non-PKA activity, assessed by the use of the PKA specific inhibitor (PKI) accounted for 49.0% and 65.0% of endogenous levels in cytosol and membrane, respectively. cAMP-augmenting drugs effects were measured and increase of 53%, 273% and 118% over basal by 10 microM isoproterenol, 100 microM forskolin, 1 microM Sp-AMP, respectively, was observed. With respect to the changes in animal age, PKA activity increased from newborn to the mature rats but decreased in older rats. The PKA ratio was higher in cytosol than in particulate fraction, and was decreased in hippocampal sample from old rats (P<0.05). This last result was interpreted as related to the loss of cognitive capacities in old animals.

The cyclic AMP-dependent protein kinase (PKA) has been involved in the brain aging process and recent papers have reported age-associated changes in enzyme activity in rat brain. The present study was undertaken to assess simultaneously PKA activity and regulatory (R) subunit levels during maturation and aging. Five cohorts of rats of different ages were used, namely pups of 1 week and 3 weeks old, mature rats (2 months), postmature rats (1 year) and old rats (2 years or more). PKA activity and 3H-cAMP binding sites were determined in cytosolic fractions of hippocampus. Results showed a low PKA activity in newborn rats which increased in mature and postmature rats and finally declined in old rats (ANOVA, P<0.001). The maximum binding sites (Bmax) of 3H-cAMP which measure the PKA R subunit levels were elevated in newborn rats and declined in mature and old rats (ANOVA; P<0.001). It is suggested the changes in PKA R subunit levels reflect an adaptative role in maturing process, a role which is lost in aging phase.

The present work was aimed at assessing the GTP-binding (Galphas subunit) protein expression in lithium-treated bipolar patients (BP). Mononuclear leukocyte Galphas protein and mRNA were measured both in patients and in a comparison group. The patient group consisted of 15 lithium-treated patients with bipolar affective disorder, all diagnosed as euthymic bipolars, and a comparison group of 15 drug-free healthy subjects. The method of competitive Reverse Transcriptase coupled to Polymerase Chain Reaction (RT-PCR) was used to estimate the relative abundance of Galphas mRNA, whereas the Western-immunoblot method was used to estimate Galphas levels. Results of both Galphas proteins and Galphas mRNA levels from patients were compared to those of non-treated control subjects. By using the competitive RT-PCR method, the Galphas mRNA displayed a significant decrease in the lithium-treated bipolar patients compared to non-treated controls: the ratio / was 1\81+/-0\05 versus 2\51+/-0\6 for BP and controls, respectively (Mann-Whitney test, < 0%sol;001). Studying the same groups with respect to their protein levels, it was shown that Galphas levels were also significantly decreased in the group of bipolar patients (normalized values to a standard yielded 81\2+/-21 per cent versus 122\5+/-25 per cent for BP and controls, respectively; Mann-Whitney test, < 0\001). Data indicated that lithium induces a decrease both in Galphas protein levels and in Galphas mRNA synthesis in BP with respect to drug-free healthy subjects. Copyright 2000 John Wiley & Sons, Ltd.

Despite numerous suggestions of the involvement of GTP-binding proteins in the mechanisms of action of psychoactive drugs in bipolar affective disorder, few studies have been conducted during the drug treatment of patients. The aim of the present study was to investigate the effects of a mood stabilizer and an antipsychotic drug on G alpha s proteins. Patients with bipolar affective disorder under lithium treatment with or without haloperidol were assessed with respect to their mononuclear leukocyte (MNL) G alpha s subunit protein. G alpha s-45 protein subunit levels were analyzed by the Western immunoblot method. The subjects consisted of a group of 20 patients, all diagnosed as euthymic bipolars, and a comparison group of 15 drug-free healthy subjects. Results showed that G alpha s levels were significantly decreased in the bipolar patients (BP) compared to drug-free healthy subjects (Mann-Whitney U test, p < 0.002). The drug effect was evaluated by a factorial analysis of variance and showed significant differences between groups (Kruskal-Wallis H test, p < 0.02). Lithium-treated patients displayed the most decreased G alpha s levels (normalized mean values 53.2 +/- 31 vs. 122 +/- 45% for BP and controls, respectively, p < 0.001), while no change was observed in G alpha s levels of haloperidol-treated patients compared to controls (mean values: 124.9 +/- 37%; NS). The data indicate that lithium and haloperidol affect the mechanism of G alpha s protein signal transduction differently, consistent with previous animal studies.

Activation of guanine nucleotide triphosphate (GTP)-binding protein by liganded-receptor was investigated in platelet membrane by measuring alpha 2-adrenergic receptor agonist (the bromoxidine or UK-14304)-induced S-35-GTP gamma S binding in the presence or absence of modulators such as magnesium, sodium chloride and guanine nucleotide diphosphate (GDP). In basal conditions, with millimolar levels of magnesium (5mM), results indicated high spontaneous, non-receptor-mediated S-35-GTP gamma S at 37 degrees C. The addition of 100mM NaCl and 2 mu M GDP reduced the absolute levels of bound radioligand, but increased the effect of the agonist. At low temperature (4 degrees C) the presence of GDP was not required for an agonist effect. If magnesium was reduced to picomolar levels (max 1 mu mol) a S-35-GTP gamma S release occurred in the presence of the alpha 2-AR agonist. These data showed, contrary to some cell systems, that platelet alpha 2-adrenoceptor required the presence of magnesium, guanine nucleotide diphosphate and sodium chloride for activation of G-protein, when the reaction was followed at physiological temperature.

Activation of guanine nucleotide triphosphate (GTP)-binding protein by liganded-receptor was investigated in platelet membrane by measuring α2-adrenergic receptor agonist (the bromoxidine or UK-14304)-induced 35 S-GTPγS binding in the presence or absence of modulators such as magnesium, sodium chloride and guanine nucleotide diphosphate (GDP). In basal conditions, with millimolar levels of magnesium (5mM), results indicated high spontaneous, non-receptor-mediated 35 S-GTPγS at 37°C. The addition of 100mM NaCl and 2μM GDP reduced the absolute levels of bound radioligand, but increased the effect of the agonist. At low temperature (4°C) the presence of GDP was not required for an agonist effect. If magnesium was reduced to picomolar levels (max 1μmol) a 35 S-GTPγS release occurred in the presence of the α2-AR agonist. These data showed, contrary to some cell systems, that platelet α2-adrenoceptor required the presence of magnesium, guanine nucleotide diphosphate and sodium chloride for activation of G-protein, when the reaction was followed at physiological temperature.

Publisher SummaryL-Tryptophan is an essential amino acid, which is required for the synthesis of proteins, Serotonin, Melatonin, and niacin. Utilization as an energy fuel depends on adequate availability of thiamin, riboflavin, vitamin B6, niacin, pantothenate, lipoate, ubiquinone, magnesium, and iron. Adequate amounts are consumed when total protein intakes meet recommendations, since dietary proteins from different sources contain Trp. The protein in milk and dairy products contains slightly more than most other food proteins; corn protein contains less. Exposure to high heat as in grilling and frying can reduce the Trp content of foods. Manufactured Trp is rarely used now, as in the past, contaminants have caused severe and irreversible harm. The same as well as related contaminants have been found in manufactured 5-hydroxytryptophan and melatonin. Prolonged lack of Trp, as of all essential amino acids or a lack of protein, causes growth failure, loss of muscle mass, and organ damage. Very high intake of protein and mixed amino acids is thought to increase the risk of renal glomerular sclerosis and accelerate osteoporosis. The consequences of very high intakes of Trp other than the known risks associated with toxic contaminants have not been adequately evaluated. Mastication of foods in the mouth, denaturation by hydrochloric acid, and unspecific protein hydrolysis by pepsin in the stomach initiate breakdown of Trp-containing proteins. Due to very effective renal reabsorption of filtered Trp, very little is lost with urine.