Divergent effects of cyproheptadine and R 50 656, a 5-HT2 antagonist, on the cardiovascular response to 5-hydroxytryptamine in rats.
Cyproheptadine and R 50 656, a novel 5-HT2 antagonist, produced a dose-dependent suppression of the pressor response to 5-hydroxytryptamine (5-HT), but did not affect the depressor response. The pressor effect of 5-HT was significantly more sensitive to R 50 656 than to cyproheptadine. On the contrary, the tachycardic response to 5-HT was antagonized only with cyproheptadine. Accordingly, in rats the 5-HT receptors of cardiac tissue differ in their pharmacological properties from both the excitatory and inhibitory 5-HT receptors of vascular smooth muscle.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D003533:Cyproheptadine / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D008297:Male; D010880:Piperidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology*
D006635:Histamine H2 Antagonists; D010880:Piperidines; D011985:Receptors, Serotonin; D003533:Cyproheptadine; D012701:Serotonin; C034177:pirenperone