RT Journal Article SR Electronic T1 Central nervous actions of serotonin and a serotonin1A receptor agonist: cardiovascular excitation at low doses. JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 425 OP 432 VO 257 IS 1 A1 A Dedeoğlu A1 L A Fisher YR 1991 UL http://jpet.aspetjournals.org/content/257/1/425.abstract AB 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.