Two classes of myocardial 5-hydroxytryptamine receptors that are neither 5-HT1 nor 5-HT2.
5-Hydroxytryptamine (5-HT) increases the sinoatrial beating rate and the force of contraction of paced left atria and papillary muscles (right ventricle) of the kitten. These effects of 5-HT are evident in tissues from noradrenaline-depleted kittens (reserpine pretreatment), and therefore elicited through myocardial 5-HT receptors. The atrial and ventricular effects of 5-HT were unaffected by concentrations of 8-OH DPAT and ketanserin saturating 5-HT1 and 5-HT2 receptors, respectively. Phenoxybenzamine blocked irreversibly sinoatrial and left atrial effects of 5-HT but not the effects of 5-HT on ventricular muscle. 5-Hydroxytryptamine causes prolongation of the ventricular action potential. Sinoatrial and left atrial 5-HT receptors are coined 5-HT3 and ventricular receptors are coined 5-HT4.
A J
AJ
Kaumann
D000818:Animals; D002415:Cats; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007650:Ketanserin; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology
D010880:Piperidines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D007650:Ketanserin