Lead contamination in fishes of the Kor River

Lead concentration in muscle, liver, kidney, brain and gonad tissues of two cyprinid fishes, Cyprinus carpio and Copoeta spp., from three sections of the upper, middle and lower parts of the Kor River was evaluated in 2006. Totally 225 specimens were caught for this purpose (75 specimens from each zone). Tissue samples were digested in acid and their lead concentrations were assayed by ICP method. Statistical analysis of data showed significantly (p0.05) were seen between sexes and species. The same pattern of contamination was also observed in water and sediment samples from three sampling zones. The maximum amount of lead measured in this study (1.85mg/kg), was, however, less than the maximum allowance in fish tissues by European Unions

Effects of Bisphenol A and Learning on the Distribution of GABAAα1 Receptors in the Rat Hippocampus and Prefrontal Cortex

Bisphenol-A (BPA) is a widely distributed chemical having mixed estrogen agonist/antagonist properties. We investigated the effects of introduction of BPA and passive avoidance learning on the distribution of GABAAα1 receptors in the rat prefrontal cortex and hippocampus. BPA (5 and 50 mg/kg·day) was introduced by oral intake for 15 days; learning and memory were tested in a shuttle-box. The distributions of GABAAα1 receptors were investigated by an immunohistochemical procedure. The BPA treatment significantly decreased the density of GABAAα1 receptors in the prefrontal cortex and hippocampus. The distribution of these receptors was significantly denser in BPA-exposed rats subjected to learning than that in rats without learning. Thus, BPA treatment leads to down-regulation of GABAAα1 receptors in the prefrontal cortex and hippocampus. Learning a passive avoidance reaction provides upregulation of such receptors in these brain structures.Бісфенол А (BPA) – це широко розповсюджений хімікат, що має змішані властивості агоніста/антагоніста естрогенів. Ми досліджували впливи введення BPA та навчання реакції пасивного уникання на розподіл ГАМКAα1-рецепторів у префронтальній корі та гіпокампі щурів. BPA (5 або 50 мг/кг на добу) вводився перорально протягом 15 діб. Результати навчання та формування пам’яті тестували в човниковій камері. Розподіл ГАМКAα1-рецепторів досліджували з використанням імуногістохімічної методики. Введення BPA істотно зменшувало кількість ГАМКAα1-рецепторів у префронтальній корі та полі CA1 гіпокампа. Розподіл цих рецепторів був значно щільнішим у щурів, котрим уводили BPA та піддавали навчанню, ніж у тварин, яким навчання не проводили. Таким чином, уведення BPA призводить до негативної регуляції системи ГАМКAα1-рецепторів у префронтальній корі та гіпокампі, тоді як навчання пасивній реакції уникання забезпечує позитивну регуляцію даної системи в згаданих мозкових структурах

Evaluation of Serum Steroid Hormones in Schizophrenic Patients

BACKGROUND: Recent studies have implicated the abnormalities in the g-aminobutyric acid (GABA) neurotransmmiter system in the pathophysiology of schizophrenia. There are also evidences indicating that steroids of central or peripheral origin may modulate GABAergic system through direct interaction with the GABAA receptor complex. These raise the possibility that alternations in serum steroid hormones may contribute to the pathophysiological process in the schizophrenia. AIMS: The purposes of this study were first, to determine whether alternations in steroid serum levels occur in schizophrenic patients, and secondly to determine whether such alternations normalize with clinical improvement. Methods and material: serum concentrations of testosterone (T), estradiol (E), progesterone (P) and cortisol (C) were determined in male schizophrenic patients (N=49) before treatment, during treatment and after recovery and in age-matched healthy male subjects (N=17). All steroid hormones were assayed by ELISA method. Statistical analysis used: Differences in steroids concentrations between groups were assayed by One-Way Analysis of Variance (ANOVA), followed by Tukey's post hoc test. The level of significance was considered at P<0.05. RESULTS AND CONCLUSION: the serum concentrations of E, P and C were significantly (P<0.05) lower in male schizophrenic patients in all three stages of the study, compared with healthy subjects. serum concentrations of T were significantly (P<0.05) lower in male schizophrenic patients before and during treatment, but not after recovery, compared with healthy subjects. These findings support the occurrence of abnormal steroid concentrations in schizophrenic patients and suggest that lower T level in this disorder is related to the illness and normalizes with remission, while trait-related factors may contribute to lower serum E and C levels in schizophrenia

Effect of xylazine and yohimbine on the phasic pain during the estrous cycle in the rat

Summary The aim of the present study was to investigate the effect of α 2 -adrenergic agonist (xylazine) and antagonist (yohimbine) on phasic pain during estrous cycle in female rats. Adult female rats weighing 180-220 g were kept under controlled temperature (21-24°C) and light/dark conditions (light on at 6:00 a.m. and light off at 6:00 p.m.). Animals were divided into four groups: 1) control group which received 0.3 ml of normal saline by intraperitoneal (IP) route; 2) IP experimental group which received 0.3 ml xylazine 3, 4.5 and 6 mg/kg and yohimbine 1, 2 and 4 mg/kg by IP route; 3) sham group which received 2 µl of artificial cerebrospinal fluid by intra cerebral ventricle (ICV) route and 4) ICV experimental which received 2 µl xylazine 10 and 20 µg/rat and yohimbine 5 and 10 µg/rat by ICV route. Cannulae were implanted into the left lateral ventricle using stereotaxic method. Pain sensitivity was measured by tail flick test, which was performed before injection, 15 and 30 min after injection in all groups. Xylazine decreased pain sensitivity significantly (P&lt;0.05) during the estrous cycle; while higher analgesia was observed in the proestrus phase for IP and ICV routes. Yohimbine increased pain sensitivity significantly (P&lt;0.05) during the estrous cycle; while higher hyperalgesia was observed in the metestrus phase for IP and ICV route groups. There was interaction (P&lt;0.05) between endogenous steroids and the α 2 -adrenergic system in the modulation of phasic pain sensitivity

Role of Peripheral Alpha2 Adrenergic Receptors in Tonic Pain During Different Stages of Estrous Cycle in Rats

Introduction: Estrogen and progesterone are supposed to modify pain sensitivity. However, the actual role of each of these steroid hormones in this respect is not well known. Plasma concentrations of these hormones show variation during estrous cycle. The role of alpha2 receptors in tonic pain has been pointed out. The aim of the present study was to investigate the agonist and antagonist effect of alpha2 adrenergic receptors on tonic pain sensitivity during all stages of estrous cycle in female rats. Methods: Xylasine as alpha2 agonist and yohimbin as alpha2 antagonist were used via intraperitoneal route (IP). Adult rats weighing 180-200 grams were used. Animals were maintained on 12h reverse light/dark cycle for 7 days prior to the experiment. Water and food was available ad libitum. Formalin test was performed by subcutaneous injection of 50 l formalin (2.5%) solution into the hind paw. Formalin test was performed in all stages of estrous cycle for 60 minutes. Animals were divided into four groups; 1- control group (intact animal), 2- Sham group (animals received 0.2 ml normal saline by IP route), 3- Agonist groups (animals received 0.2 ml xylasine 1, 3 mg/kg body weight by IP route) and 4- Antagonist group (animals received 0.2 ml yohimbine 1, 3 mg/kg body weight by IP route). Data were statistically analyzed using 2 way ANOVA test followed by Tukey's test as post-hoc test. P<0.05 was considered significant. Results: Results showed that xylasine significantly (p<0.05) decreases pain sensitivity in all stages of estrous cycle. Analgesic effect of xylasine was maximum in estrus stage of estrous cycle and minimum in metestrus stage of estrous cycle. Yohimbine significantly (p<0.05) increases pain sensitivity in all stages of estrous cycle. Hyperalgesic effect of yohimbine was maximum in metestrus stage of estrous cycle and minimum in estrus stage of estrous cycle. Conclusion: These results indicate that alpha2 adrenergic system and endogenous steroids have an important role in pain sensitivity

Interaction of Electromagnetic Field and Modulation of GABA-B Receptor on Serum Testosterone Concentration in Aggressive Rats

Introduction: The aim of the present study is to investigate the effect of interaperitoneal injection of baclofen (GABA-B agonist) and CGP35348 (GABA-B antagonist) on serum testosterone concentration in aggressive rats exposed to electromagnetic field. Methods: Fifty five mature male rats weighing 200±20 grams were studied. Animals were divided into 2 main groups and four subgroups. Main groups composed of rats with and without exposure to electromagnetic field. Animals in the former group were exposed to electromagnetic field with 500 T intensity and 50Hz frequency for 8 hours a day for 30 days. Aggression was induced by applying 2mA current every 3 seconds for 5 minutes. Then serum testosterone concentration was measured by radioimmunoassay method. Results: Data showed that baclofen injection at 3mg/kg and CGP35348 at 100mg/kg significantly increased serum testosterone concentration in aggressive rats exposed to electromagnetic field. Conclusion: According to the simillar effect of baclofen and CGP35348 on testosterone secretion, it seems that GABA-B receptors in testes are two types, so it has caused similar effects. Also, electromagnetic exposure leads to increase in testosterone secretion

Rapid actions of the neurosteroid allopregnanolone on ovarian and hypothalamic steroidogenesis: Central and peripheral modulation

The present study aimed to determine whether an i.c.v. administration of allopregnanolone (ALLO) rapidly modifies the hypothalamic and ovarian 3β‐hydroxysteroid dehydrogenase (3β‐HSD) enzymatic activity and gene expression in in vivo and ex vivo systems in pro‐oestrus (PE) and dioestrus I (DI) rats. Animals were injected with vehicle, ALLO, bicuculline or bicuculline plus ALLO and were then killed. In the in vivo experiment, the hypothalamus, ovaries and serum were extracted and analysed. In the ex vivo experiment, the superior mesenteric ganglion ‐ ovarian nerve plexus ‐ ovary system was extracted and incubated during 120 minutes at 37 ºC. The serum and ovarian compartment fluids were used to determine progesterone by radioimmunoanalysis. In the in vivo experiments, ALLO caused a decrease in hypothalamic and ovarian 3β‐HSD enzymatic activity during PE. During DI, ALLO increased hypothalamic and ovarian 3β‐HSD activity and gene expression. The ovarian 3β‐HSD activity increased in both stages in the ex vivo system; gene expression increased only during DI. ALLO induced an increase in serum progesterone only in D1 and in the ovarian incubation liquids in both stages. All findings were reversed by an injection of bicuculline before ALLO. Ovarian steroidogenic changes could be attributed to signals coming from ganglion neurones, which are affected by the acute central neurosteroid stimulation. The i.c.v. administration of ALLO via the GABAergic system altered 3β‐HSD activity and gene expression, modulating the neuroendocrine axis. The present study reveals the action that ALLO exerts on the GABAA receptor in both the central and peripheral nervous system and its relationship with hormonal variations. ALLO is involved in the “fine tuning” of neurosecretory functions as a potent modulator of reproductive processes in female rats.Fil: Cáceres Gimenez, Antonella Rosario Ramona. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina. Universidad "Juan Agustín Maza". Facultad de Ciencias Veterinarias y Ambientales; ArgentinaFil: Vega Orozco, Adriana Soledad. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas. Laboratorio de Biología de la Reproducción; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Cabrera Kreiker, Ricardo Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Laconi, Myriam Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentin