Central nervous actions of serotonin and a serotonin1A receptor agonist: cardiovascular excitation at low doses.
Studies were performed in conscious unrestrained rats to compare the cardiovascular effects of i.c.v. administration of serotonin (5-HT) and the 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). Low doses (less than 10 nmol) of 5-HT and 8-OH-DPAT elicited significant elevations of arterial pressure and heart rate. At doses greater than 10 nmol, 5-HT produced pressor responses attended by significant reductions of heart rate whereas 8-OH-DPAT produced significant depressor and bradycardiac responses. Concurrent i.c.v. administration of the nonselective 5-HT receptor antagonist, methiothepin, abolished the cardiovascular responses to a low (1 nmol) and a high (100 nmol) dose of 5-HT and a low (3 nmol) dose of 8-OH-DPAT. In contrast, methiothepin cotreatment did not prevent the reductions of arterial pressure and heart rate induced by a high (100 nmol) dose of 8-OH-DPAT. These results suggest that stimulation of central nervous system 5-HT1A receptors with low doses of 8-OH-DPAT produces cardiovascular activation.
Dedeoğlu
A
A
Department of Pharmacology, University of Arizona College of Medicine, Tucson.
Fisher
L A
LA
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D008719:Methiothepin / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D013764:Tetrahydronaphthalenes / Q000008:administration & dosage / Q000494:pharmacology*
D011985:Receptors, Serotonin; D013764:Tetrahydronaphthalenes; D012701:Serotonin; D008719:Methiothepin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin