Introduction: Previous studies have investigated the effects and importance of orexin and estradiol on food intake. In this study the effects of orexin on estradiol release by the ventromedial hypothalamus (satiety center) and lateral hypothalamus (feeding center) have been investigated.Forty adult male rats, divided to two groups, the control group (consisting of 10 rats) and an experimental group (consisting of 30 rats), were canulated in the lateral area and ventromedial nucleus steriotaxically. After two days recovery, 1, 2 and 4 micrograms of orexin were injected into the lateral area and ventromedial nucleus. After two hours, tissue of the lateral area and ventromedial nucleus were removed and concentrations of estradiol and aromatase were measured by radio-immuno assay and RT-PCR, respectively. Results of RT-PCR showed that orexin-A (1, 2, 4 mg) augmented aromatase gene expression in the VMH and LH.17-b estradiol measurement showed that 1, 2 and 4mg orexin infusion increased estradiol levels significantly in VMH and LH, especially the 2 and 4mg doses, observations suggesting that the neurons secreting estradiol exist in the VMH and LH.

Background: Ventromedial (VMH) and Lateral (LH) hypothalamus are involved in central, but not peripheral. stimulation of gastric acid secretion (GAS). There are some evidences that glucose, an inhibitor of central- stimulated GAS, acts on glucosensitive neurons in VMH and LH. Evidences suggest that decreasing central stimulation of GAS is mediated by reciprocal connection between VMH and LH. The present study was designed to investigate the effect of lateral hypothalamic lesion on the effect of D-glucose microinjection into VMH on pentagastrin induced GAS.Materials and methods: The animals were anesthetized and placed in a stereotaxic instrument and guide cannulas were bilaterally implanted above (1 mm) VMH after bilateral electrolytic lesions of the lateral hypothalamus. Seven days after implantation, two polyethylene tubes were inserted into the stomach through esophagus and duoedonopyloric junction in anesthetised rat. After washing of the stomach with saline prewarmed to 370C for 15 min., the gastric secretory volume were collected at 5 minutes intervals. Fourty minutes after starting the intravenous injection of pentagastrin (2µg/100g/hr), D-glucose (30mM) was injected into the VMH.Results: Intravenous infusion of pentagastrin induced marked increase in GAS with a peak starting from 30 min up to the end of the experiments. In LH-lesioned rats, pentagastrin stimulated GAS was lower than that in sham-groups. Microinjection of D-glucose, but not L-glucose or saline, decreased gastric acid output in sham groups. No significant change in the acid output was noted after D-glucose injection into the VMH in LH-lesioned rats.Conclusion: Our findings show that 1) There are GAS-type glucosensitive neurons in VMH which affect the pentagastrin stimulated GAS. 2) GAS-type glucosensitive neurons arent sensitive to osmolarity, 3) The part of peripheral stimulation of GAS by pentagastrin is mediated by reciprocal connection between LH and VMH. 4) LH neurons appear to play a significant role in pentagastrin stimulated GAS.

The goal of this study was to find out whether the change in saliva secretion is the primary effects of these agents or there are subsequences of taking food, lick, swallowing and digestion in the mouth. In this study, 70 rats were stereotaxically implanted under urethane anesthesia. The rats were divided into 7 groups: one control group, two sham groups given medicine solvents, two sulpiride groups (4mg and 8 mg), one bromocriptine group (25 mg) and a mixed group: sulpiride 8 mg along with bromocriptine 25 mg. In this study, saliva secretion was gathered from submandibular glands by cannulas and measures then volume of secretion by using SPSS program the groups were compared (Test Anova). The saliva secretion was not significantly different between all groups except sulpiride 8 mg group and a mixed group which showed significant differences in the saliva secretion. This study showed that sulpiride (8 mg) could increase saliva secretion, while sulpiride (4 mg) couldn’t increase saliva secretion. Bromocriptine (25 mg) could not affect saliva secretion. However, bromocriptine (25 mg) along with sulpiride 8 mg significantly increased saliva secretion. So the dopaminergic system of the VMN has a considerable effect on the secretion the exocrine glands in the digestive system.

Morphine has adverse effects on the female reproductive system. The aim of this study was to investigate the interference effects of MgSO4 (intra ventromedial hypothalamus (VMH) and naloxone in the rat with polycystic ovaries induced by morphine. 80 female rats (200-250 g) kept under standard conditions were surgically coordinated (Anterior-Posterior:-1/92, Ventral: 9, Lateral: 0. 5) using a stereotactic device. After recovery they were microinjected morphine (0. 1-0. 4 µ g/rat, intra-VMH) and pre-injected naloxone hydrochloride (0. 1-0. 4 µ g/rat, intra-VMH) and also MgSO4 (1-5 µ g/rat) prior to the naloxone. The control group received physiological saline (1 µ L/rat, intra-VMH). 3 days after the experiment, uterus, ovary and brain samples were collected and studied histopathologically using hematoxylin & eosin. The ovaries in group in which morphine was injected showed polycystic features as compared to the control group. This effect was reversed by the naloxone pre-injection, but, prior treatment with MgSO4 returned the aspect. However, this substance alone did not have a significant effect on the ovaries. In addition, the inflammatory effect of morphine on the ovary and the uterus was reversed with pre-injection of naloxone, but it was also returned by the MgSO4. These materials did not have significant effect on neurons of VMH. These results indicate that the effect of morphine is mediated by mu opioid receptor which is dependent to the calcium ion signalling mechanism.

Background and Objective: Polycystic ovary syndrome (PCOS) is a reproductive disorder that causes infertility. Morphine, when injected into the ventromedial hypothalamus (VMH), is effective in inducing PCO, but the mechanism of this effect, particularly concerning dopamine (DA), remains unclear. The study aims to understand how DA and its receptors contribute to this disruption. Materials and Methods: Virgin animals weighing 220-250 g and aged 8-9 weeks were randomly divided into control, morphine alone, sulpiride alone, and sulpiride + morphine groups that received sulpiride before an effective dose of morphine. Morphine (0.1-0.4 μg/rat) was injected into the VMH (AP coordinates: -1.92; ventral: 9 mm; lateral: 0.5 mm). Sulpiride (0.1-0.4 μg/rat) was injected intra-VMH alone or before morphine (0.4 μg/rat, intra-VMH). The control group received saline merely (1 μL/rat, intra-VMH). The animals were anesthetized three days later, and after surgery, the ovaries, uterus, and brain were collected and examined in 10% formalin. All data were statistically analyzed. Results: Ovaries of rats treated with morphine and not in the sulpiride single groups showed PCO features compared to the control group; however, the number of cysts was significantly reduced in the sulpiride + morphine samples. Morphine and sulpiride did not significantly induce uterine inflammation. Moreover, no significant effect on VMH neurons was observed in any of the groups. Conclusion: These results indicate that morphine disrupts follicular growth and that this effect is partially reversed by blocking DA type 2 receptor signaling.

Introduction: In this study, the regulatory role of the ventromedial nucleus (VMN) of the hypothalamus on pituitary gland secretion, was studied. We investigated the influence of D2 receptors of the VMN on serum levels of sex hormones and prolactin. Materials and Methods: 35 adult male rats, weighing between 280-320g, were selected and cannulae were implanted bilaterally into the VMN. After the recovery period, rats were divided into 5 groups: sul (injected 8 g sulpiride), sham-s (injected vehicle), Bromo (injected 25 g bromocriptin), sham b-operated (injected vehicle), S+B (injected sulpiride Bromcriptine). The drugs were injected daily into the VMN (0.5µl/min) for 7 days, 0.5 hours after the last injection, the animals were decapitated and blood samples were collected. Serum levels of sex hormone and prolactin were measured by RIA method. Results: The results of this study indicate that sulpiride and (or) Bromocriptine cannot change the serum level of prolactin, testosterone and estradiol but sulpiride increases serum level of progesterone and decreases the estradiol progesterone ratio, Bromocriptin showed the reverse effects. Conclusion: We conclude that D2 receptors of VMN have a role in the regulation of sex hormone secretion.

Introduction: Dopamine is one member of catecholamine, which has a crusial role in the regulation of feeding behavior. The Peripheral injection of dopamine agonistssuch as bromocriptine causes anorexia. The aim of this study is to show how this drugacts. The reason for this selection is due to its importance in the regulation of food intake. Materials & Methods: Sixty three adult male rats (280-320 gw) were used. The rats were divided in to nine groups as follows: control, sham B (injected vehicle of bromocriptine), Br12.5, Br25, Br50 (injected bromocriptin respectively 12.5,25 and g), SBr (injected sulpiride + bromocriptine), ScBr (injected ScH2339 + bromocriptine), ShSBr and ShScBr of which the last two cases are sham respectively. The injection intervals were 24h, which took 7 days. All of them were bilaterally. Food, water intake and weight measured 24 hours after each injection and the following results were obtained. Results: Bromocriptine showed a decrease in food, water intake and weight gain. Sulpiride antagonized the effects of bromocriptine on food, water intake and weight gain. ScH23390 caused no significant changes in bromocriptine effects on food, water intake and weight gain. Conclusion: These results indicate that, the D2 dopamine receptors of VMN have acrusial role in decreasing effects of bromocriptine on feeding behaviors.

Injection of sulpiride (D2 receptor antagonist, antipsychotic drug) into VMN hypothalamus, increased gastric volume secretion and decreased gastric pH. The present study the effect of SCH23390 (D1 dopamine receptor antagonist) on the gastric acid secretion and its acidity were studied.70 rats were divided into 7 groups: two control groups, two sham groups given medicine solvents, a SCH23390 group (7.5 mg), and bromocriptine group (25 mg) and a mixed group: SCH23390 7.5μg along with bromocriptine 25μg. Gastric secretion volume was taken by syringe 2CC and by using SPSS program the groups were compared (Test Anova). Results showed that SCH23390 group (7.5 mg) could increase volume of gastric secretion and decrease gastric acidity, while Bromocriptine (25 mg) could not affect gastric volume secretion and its acidity. However, bromocriptine (25 mg) along with SCH23390 7.5μg significantly increased gastric volume secretion and its acidity. So the dopaminergic system of the VMN has a considerable effect on the secretion of the exocrine glands in the digestive system.