Central injection of neuropeptide Y modulates sexual behavior in male rats: interaction with GnRH and kisspeptin/neurokinin B/dynorphin.

AIMS: A number of studies have shown that neuropeptide Y (NPY) is considered to be one of the key regulators of hypothalamic-pituitary-gonadal (HPG) axis in the mammals. In addition, kisspeptin (encode by Kiss1 gene), neurokinin B (encode by Tac3 gene) and dynorphin (encode by Pdyn gene) (commonly known as KNDy secreting neurons) are a powerful upstream regulators of GnRH neuron in hypothalamus. MATERIALS AND METHODS: The present study aims to investigate the effects of the intracerebroventricular (icv) injection of NPY and BIBP3226 (NPY receptor antagonist (NPYRA)) on the male sexual behavioral. Additionally, in order to see whether NPY signals can be relayed through the pathway of kisspeptin/neurokinin B/dynorphin, the gene expression of these peptides along with Gnrh1 gene in the hypothalamus were measured. RESULTS: The icv injection of NPY decreased the latencies and increase the frequencies of sexual parameters of the male rats in a significant way. In this line, NPYRA antagonized the stimulative effects of NPY. Moreover, data from real-time quantitative PCR indicated that injection of NPY significantly increased the gene expression of Gnrh1, Kiss1 and Tac3 and decrease the Pdyn while treatment with NPYRA controlled the modulative effects of NPY on these gene expression. CONCLUSIONS: In conclusion based on the results of this study, NPY can exert its impacts on the sexual behavior of male rats via modulation of the KNDy secreting neurons as an interneural pathway to GnRH neurons.

Probiotics and Nigella sativa extract supplementation improved behavioral and electrophysiological effects of PTZ-induced chemical kindling in rats.

INTRODUCTION: Epilepsy is a most common neurological disorder that has negative effects on cognition. In the present study, we investigated the protective effect of Nigella sativa (NS) and probiotics on seizure activity, cognitive performance, and synaptic plasticity in pentylenetetrazole (PTZ) kindling model of epilepsy. METHODS: One hundred and forty-four rats were divided into 2 experiments: In experiment 1, animals were grouped and treated as follows: 1) control (PTZ + saline), 2) NS treatment, 3) probiotic treatment, and 4) NS and probiotic treatment. Six weeks after the treatment, PTZ kindling were performed, and 48 h after kindling, spatial learning and memory were measured in Morris water maze (MWM) test. Animals in experiment 2 received the same treatment as experiment 1: in control nonkindled groups, control animals were treated with probiotics, NS, and probiotics + NS. Six weeks after the treatment, PTZ kindling were performed, and 48 h after kindling, field potentials were recorded from the dentate gyrus area of the hippocampus; synaptic transmission and long-term potentiation (LTP) was measured. RESULTS: The results showed that the probiotic and NS supplementation significantly reduces kindling development so that animals in PTZ + NS + probiotic did not show full kindling. In MWM test, the escape latency and traveled path in the kindled group were significantly higher than the control group. In PTZ + NS + probiotics, these parameters were significantly lower than those in the PTZ + saline group. Adding probiotic and NS supplementation significantly reduced population spike (PS)-LTP as compared with the PTZ + saline group. CONCLUSION: Probiotic and NS supplementation have some protection against seizure, seizure-induced cognitive impairment, and hippocampal LTP in kindled rats.

ERK activation is required for the antiepileptogenic effect of low frequency electrical stimulation in kindled rats.

INTRODUCTION: The signaling pathways involved in the antiepileptogenic effect of low frequency electrical stimulation (LFS) have not been fully understood. In the present study the role of extracellular signal-regulated kinase (ERK) signaling cascade was investigated in mediating the inhibitory effects of LFS on kindled seizures. METHODS: Animals received kindling stimulations for seven days (the mean number of stimulation days for achieving stage 5 seizure) according to semi-rapid perforant path kindling protocol (12 stimulations per day at 10 min intervals). LFS (0.1 ms pulse duration at 1 Hz, 800 pulses) was applied at 5 min after the last kindling stimulation every day. During the kindling procedure, FR180204 (inhibitor of ERK) was daily microinjected (1 µg/µl; intracerebroventricular) immediately after the last kindling stimulation and before LFS application. The expression of activated ERK (p-ERK) in the dentate gyrus was also investigated using immunohistochemistry technique. RESULTS: Application of LFS at 5 min after the last kindling stimulation had inhibitory effect on kindling rate. FR180204 had no significant effect on seizure parameters when administered at the dose of 1 µg/µl in kindled group of animals. However, microinjection of FR180204 before LFS application reduced the inhibitory effect of LFS on seizure severity and field potential parameters (i.e. the slope of population field excitatory postsynaptic potentials and population spike amplitude) during kindling. FR180204 also blocked the preventing effects of LFS on kindling-induced increase in early (at 10-40 ms intervals) and late (at 300-1000 ms intervals) paired pulse depression. In addition, application of LFS following kindling stimulations increased the expression of p-ERK in the dentate gyrus. CONCLUSION: Obtained results showed ERK signaling pathway had important role in mediating the antiepileptogenic effect of LFS in perforant path kindling. These findings represent a promising opportunity to gain insight about LFS mechanism in epilepsy therapy.

Antinociceptive and anti-inflammatory effects of the aerial parts of Artemisia dracunculus in mice.

CONTEXT: Tarragon (Artemisia dracunculus L., Asteraceae) is an ancient herb, which is widely used as a medicine, flavoring, or fragrance. OBJECTIVE: To determine the antinociceptive and anti-inflammatory effects of aerial parts of tarragon, we investigated the effects of ethanolic extract of the plant in adult male Balb/c mice. MATERIALS AND METHODS: Antinociceptive activity was determined using formalin, hot-plate, and writhing tests. The effect of the ethanolic extract on acute inflammation was evaluated by xylene-induced ear edema in mice. The ethanolic extract was administered at doses of 5, 10, 50, and 100 mg/kg, i.p. The control group received saline as vehicle of ethanolic extract. RESULTS: Our results showed that the ethanolic extract (50 and 100 mg/kg) decreased both phases of pain in the formalin test (ED50 = 109.66 and 87.13 mg/kg, respectively). In the hot-plate test, the extract (50 and 100 mg/kg) increased pain threshold during 60 min (ED50 = 81.03 mg/kg). The extract (50 and 100 mg/kg) exhibited antinociceptive activity against acetic acid-induced writhing (ED50 = 66.99 mg/kg). The extract (50 and 100 mg/kg) showed significant activity in the xylene ear edema test (ED50 = 78.20 mg/kg). Pretreatment of the animals with naloxone decreased the analgesia induced by the extract in hot-plate and formalin tests; therefore, opioid receptors may be involved, at least partly, in the analgesic effect of tarragon extract. DISCUSSION AND CONCLUSION: The results suggested that tarragon have significant analgesic and anti-inflammatory effects in mice, and, therefore, further studies are required to evaluate these effects and additional potential of the plant.

Protective effect of Tribulus terrestris hydroalcoholic extract against cisplatin-induced cytotoxicity on sperm parameters in male mice / Efecto protector del extracto hidroalcohólico de Tribulus terrestris contra la citotoxicidad inducida por cisplatino sobre parámetros espermáticos en ratones macho

Cisplatin is an anti-cancer drug used in chemotherapy. One of the limiting side effects of cisplatin is decreasing genital gland function, azoospermia and oligospermia. Tribulus terrestris has been used as an aphrodisiac. The present study amid to investigate protective effect of Tribulus terrestris hydroalcoholic extract against cisplatin-induced cytotoxicity on sperm parameters in mice. Male adult mice (n=30) were divided into control and 4 experimental groups (n=6). Control group received saline, first experimental group received cisplatin (5.5 mg/kg) and other three experimental groups received cisplatin (5.5 mg/kg) and different doses of hydroalcoholic extact of Tribulus terrestris (100, 300 and 500 mg/kg/i.p) respectively. On the day after the last injection, blood samples were collected for serum Nitric oxide (NO) assay. Also weights of body and testis, sperm parameters and seminiferous tubules diameter were assessed. Data analysis was performed using one-way ANOVA followed by Tukeys' test. The results showed that cisplatin lead to a reduction in the weight of body and testes, sperm parameters and increased level serum of NO significantly compared to the control group (P<0.05), while in treated groups with Tribulus terrestris, the weights of body and testes, sperm parameters, seminiferous tubules diameter were significantly higher compared with cisplatin group (P<0.05), but serum level of NO did not show significant differences. The study demonstrates that extract of Tribulus terrestris could protective effect against cisplatin- induced cytotoxicity on sperm parameters that may be related to the presence of antioxidant components acting via a multitude of central and peripheral mechanisms.

El cisplatino es un medicamento contra el cáncer utilizado en la quimioterapia. Uno de los efectos secundarios limitantes de cisplatino es la decreciente función glándular genital, azoospermia y oligospermia. Tribulus terrestris ha sido utilizado como un afrodisíaco. En el presente estudio se investiga el efecto protector del extracto hidroalcohólico de Tribulus terrestris (TT) contra la citotoxicidad inducida por cisplatino en los parámetros espermáticos en ratones. Ratones adultos machos (n = 30) fueron divididos en 4 grupos control y experimentales (n = 6). En el grupo control se administró solución salina, el primer grupo experimental recibió cisplatino (5,5 mg/kg) mientras que otros tres grupos experimentales recibieron cisplatino (5.5 mg/kg) además de diferentes dosis de extracto hidroalcohólico de TT (100, 300 y 500 mg/kg/IP) respectivamente. El día siguiente de la última inyección, se analizaron muestras de sangre para expresión de óxido nítrito (ON). Además, fueron evaluados el peso del cuerpo y testículos, los parámetros espermáticos y el diámetro de los túbulos seminíferos. Los datos fueron analizados mediante análisis ANOVA y la prueba de Tukey. El uso de cisplatino causó reducción del peso corporal y testicular, parámetros espermáticos y aumento significativo de los valores de ON en comparación con el grupo control (P<0,05), mientras que los grupos tratados con TT, fue significativamente mayor el peso corporal y testicular, parámetros espermáticos y diámetro de los túbulos seminíferos en comparación al grupo tratado con cisplatino (P<0,05). No se observaron diferencias significativas en los valores ON. El extracto de TT puede tener un efecto protector frente a la citotoxicidad inducida por el cisplatino sobre los parámetros espermáticos, al estar relacionado a la presencia de componentes antioxidantes que actúan mediante mecanismos centrales y periféricos.

Possible Modulation of the Anexiogenic Effects of Vitex Agnus-castus by the Serotonergic System.

OBJECTIVES: There is well documented evidence for the increase in widespread use of complementary and alternative medicine in the treatment of physical and psychiatric symptoms and disorders within the populations. In the present study, we investigated the influence of V itex agnus-castus (vitex) on anxiety-like behaviors of rats. MATERIALS AND METHODS: Elevated plus maze which is one of the methods used for testing anxiety is used in our present study. Rats were orally administrated with vitex for two week. The anxiety test was carried out after two weeks of oral administration of vitex. For evaluating interaction of vitex and serotonergic systems, rats were anaesthetized with ketamine and special cannulas were inserted stereotaxically into the third ventricle (TV) of brain. After 1 week recovery, the effects of serotonegic agents on anxiety were studied. RESULTS: Oral administration of vitex (100, 200, 300 mg/kg) for two weeks induced an anxiogenic-like effect which was shown through specific decreases in the percentages of open arm time (OAT %) and open arm entries (OAE %). Intra - TV infusion of 5HT1A receptor agonist, 8-OH-DPAT (5, 10 and 25 ng/rat) increased OAT% and OAE%, indicating anxiolytic-like behavior. However, injection of 5HT1A receptor antagonist NAN190 (0.25, 0.5 and 1 µg/rat) produced anxiogenic-like behavior. The most effective dose of 8-OH-DPAT (10 ng/rat), when co-administered with vitex (100, 200, 300 mg/kg), attenuated the anxiogenic-like effects of vitex significantly. Injection of the less effective dose of NAN190 (0.5 µg/rat), in combination with vitex (100, 200, 300 mg/kg), potentiate anxiogenic effects of vitex. CONCLUSIONS: These results illustrate that 5HT1A receptor is involved in the anxiogenic effects of vitex.