بررسي اثرات سيستم H2 - هيستامينرژيك و 1 - آدرنرژيك بر اخذ آب در موشهاي صحرايي نر بالغ

Effect of H2- histaminergic and «i - adrenergic systems on water intake in adult male rats

Thirst is controlled by multiple excitatory and inhibitory stimuli related to body-fluid dehydration. Evidence for an inhibitory role of ai-adrenergic receptors in thirst and sodium appetite has been gathered over the past three decades. On the other hand, central histaminergic neurons have been implicated in many physiological processes, such as circadian rhythms, thermoregulation, acquisition and memory and cardiovascular and neuroendocrine regulations. Several lines of evidence also suggested that neuronal histamine might be involved in the control of water intake. It has been suggested that peripheral mechanisms may also be involved in the dipsogenic effect of histamine. Because the amine elicits drinking even after its systemic administration. The present study investigated the interaction between H2-histaminergic and ai-adrenergic systems on water intake in adult male rats. Intraperitoneally (i.p.) injections were carried out in all experiments after 24-h deprivation of water. After deprivation, the volume of consumed water was measured for 1 h. Administration of histamine (1-5 mg/kg wt.) and prazocin (0.01-1 mg/kg wt.) increased, while ranitidine (10-50 mg/kg wt.), phenylephrine (0.01-5 mg/kg wt.) decreased water intake in rats. Blockade of histamine H2 receptors attenuated the histamine-induced response. Pretreatment with ranitidine attenuated the prazocin-induced response. Phenylephrine didnʹt increase the inhibitory effect induced by ranitidine. It is concluded that H2-histaminergic system may have a close interaction with on -adrenergic system on drinking behavior.