Effects of alpha(1)-adrenoceptors and muscarinic cholinoceptors on water intake in rats.
The present study investigated the effects of alpha(1)-adrenoceptors and muscarinic cholinoceptors on water intake in adult male rats. Intracerebroventricular (i.c.v.) 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 pilocarpine, a muscarinic cholinoceptor agonist (0.5-1 microg/rat), and prazosin, the alpha(1)-adrenoceptors antagonist (2 microg/rat), increased, while scopolamine, a muscarinic cholinoceptor antagonist (5-10 microg/rat), and phenylephrine, an alpha(1)-adrenoceptor agonist (30 microg/rat), decreased water intake in rats. The activation of muscarinic cholinoceptors by pilocarpine attenuated the inhibitory effect induced by phenylephrine. Blockade of muscarinic cholinoceptors did not change the phenylephrine-induced response. Pretreatment with prazosin decreased the pilocarpine-induced response. However, pharmacological blockade of muscarinic cholinoceptors by scopolamine decreased the prazosin-induced effect on water intake. It is concluded that muscarinic cholinoceptors and alpha(1)-adrenoceptors may interact on water intake.
D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D004326:Drinking / Q000187:drug effects* / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D018721:Muscarinic Agonists / Q000008:administration & dosage / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D010656:Phenylephrine / Q000008:administration & dosage / Q000494:pharmacology; D010862:Pilocarpine / Q000008:administration & dosage / Q000494:pharmacology; D011224:Prazosin / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*; D012601:Scopolamine / Q000008:administration & dosage / Q000494:pharmacology
D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D018340:Receptors, Adrenergic, alpha-1; D011976:Receptors, Muscarinic; D010862:Pilocarpine; D010656:Phenylephrine; D012601:Scopolamine; D011224:Prazosin