Introduction: Brain insulin receptors (IRs) have been suggested as an important regulatory factor for cognitive functions but the involvement of IR signaling in memory deficit associated with neurodegenerative conditions is not yet explored. Among the diverse signaling pathways of IR, PI-3 kinase and (MAP) kinase pathways in brain have been suggested for learning and memory functions. The phosphoinositide3-kinase (PI3K) complex plays important roles in virtually all cells of the body. The enzymatic activity of PI3Kto phosphorylate phosphoinositides in the membrane is mediated by a group of catalytic and regulatory subunits. Among those, the class I catalytic subunits, p110α , p110β , p110γ , and p110δ have recently drawn attention in the neuroscience field due to their specific dysregulation in diverse brain disorders. The present study was planned to investigate the effect of PI3K on memory. Materials and Methods: The animals were injected bilaterally with ICV water (control group), ICV PI3k (1, 10 and 100 ng/rat) on days 1 and 3 after surgery. The learning and memory performance was assessed two weeks after the first dose of drugs by using step-through passive avoidance paradigm (0. 3 mA, 3seconds) and open field test. The results revealed that The ICV administration of PI3K (P<0. 05) altered inhibitory avoidance acquisition. PI3K at dose 1 ng/rat decreased the step-through latency during the retention test. Results: data showed that PI3K at dose of 1 ng/rat decreased the step-through latency during the retention test. In addition, the results showed that PI3K at dose 10 ng/rat increased locomotor activity. Conclusion: Finally, our data indicated that PI3K has critical role in memory consolidation and locomotor activity.

Previous studies have shown that galanin is an orexigenic peptide that inhibits the activity of Hypothalamus –Pituitary – Thyroid (HPT) axis. It is also proved that galanin increases food intake via neuropeptide Y pathway. Morphine is an alkaloid opiates that effect on thyroid hormones concentration via Agouti Related Protein and increases dopaminergic neurons activity in median eminence. The aim of this study was to determine the influence of the interaction between galanin and morphine on thyroid hormones concentration. Twenty-one male Wistar rats (200-250 g) were randomly divided 3 groups. The groups received 200ng galanin, 1mg morphine and 200ng galanin together with 1mg morphine in third cerebral ventricle in volumes of 3 ml. Blood samples were collected one day before injection and untill 24 hours after that. The plasma was analyzed by Radioimmunoassay technique to determine T3 and T4 concentrations. Brain slices were taken to ensure that the place of the canulae was right. The results indicated that galanin or morphine significantly decreased thyroid hormones concentration after injections compared to before injection (p<0.05). Simultaneous injections of galanin and morphine causes more inhibitory effect on HPT axis activity (p<0.05).

This study was aimed to investigate the function of opioidergic receptors on mediating the role histamine on central control of broiler feed intake. In this research, the role of mu, kappa and delta receptors of opioids on hypophagia induced by ICV injection of histamine was investigated in three separate experiments.In each experiment, 48 Ross 308 5-day broilers were randomly divided into 4 groups (12 birds per group) and the birds were given one of the four experimental treatments by ICV injection after 3 hours of feed deprivation. Experimental groups included of 1) normal saline (control), 2) 300 nmol histamine 3) 5 μg opioid receptor antagonist (mu receptor antagonist in the first experiment, kappa in the second experiment and delta in the third experiment) and 4) co-injection of histamine (300 nmol) and opioid receptor antagonist (5 μg). The cumulative intake of feed was measured after injection at 30, 60, and 120 minutes. Results showed that histamine injection in all three experiments reduced feed intake. Co-administration of the mu opioid receptor antagonist and histamine reduced the hypophagic effects of histamine and increased feed intake. However, histamine and kappa or delta receptor antagonists co-administered did not increase the intake of histamine-induced feed. Overall, the results of this study show that the mu opioid receptor mediates at least part of the histamine-induced hypophagic effect in broilers, while kappa and delta opioid receptors have no significant effect.

This study was aimed to investigate the function of opioidergic receptors on mediating the role histamine on central control of broiler feed intake. In this research, the role of mu, kappa and delta receptors of opioids on hypophagia induced by ICV injection of histamine was investigated in three separate experiments. In each experiment, 48 Ross 308 5-day broilers were randomly divided into 4 groups (12 birds per group) and the birds were given one of the four experimental treatments by ICV injection after 3 hours of feed deprivation. Experimental groups included of 1) normal saline (control), 2) 300 nmol histamine 3) 5 μ g opioid receptor antagonist (mu receptor antagonist in the first experiment, kappa in the second experiment and delta in the third experiment) and 4) co-injection of histamine (300 nmol) and opioid receptor antagonist (5 μ g). The cumulative intake of feed was measured after injection at 30, 60, and 120 minutes. Results showed that histamine injection in all three experiments reduced feed intake. Co-administration of the mu opioid receptor antagonist and histamine reduced the hypophagic effects of histamine and increased feed intake. However, histamine and kappa or delta receptor antagonists co-administered did not increase the intake of histamine-induced feed. Overall, the results of this study show that the mu opioid receptor mediates at least part of the histamine-induced hypophagic effect in broilers, while kappa and delta opioid receptors have no significant effect.

In this study the effects of intracerebroventricular (ICV) injection of histamine, its H1 and H2 antagonists were examined on food/water intake ratio in the rabbit. The ICV injections of artificial cerebrospinal fluid (a CSF: control), histamine, chlorpheniramine (H1 antagonist) and cimetidine (H2 antagonist) were Gone through a cannula which were surgically implanted into the lateral ventricle of the brain. The results showed that the histamine at dose rate of 50mg decreased the first food/water intake ratio, where as histamine (100 mg) decreased the first and 3h post-injection of above mentioned ratio. The ICV injection of chlorpheniramine alone increased the first and 3h food/water intake ratio, and pretreatment by chlorpheniramine inhibited the effects of histamine. ICV injection of cimetidine alone and or its pretreatment had no effect. Histamine, chlorpheniramine and cimetidine had no effect on 24h post-injection food/water intake ratio. No significant changes were observed among control groups. It is concluded that the brain histaminergic system can affect the short-term regulation of food, water and food-related water intake. The inhibitory effect of histamine on food intake is mediated through its central H1 receptor and on water intake anti food-related drinking both central H1 and H2 receptors don't play any role.