5-Hydroxytryptamine induces endothelium-independent relaxations of sheep pulmonary vein: role of cyclic nucleotide.
5-Hydroxytryptamine produced concentration-dependent relaxations in isolated sheep pulmonary vein, which were insensitive to removal of the endothelium. 5-Hydroxytryptamine stimulated concentration-dependent increases of cyclic AMP levels in the pulmonary vein, and there was a significant linear correlation between relaxations elicited by 5-hydroxytryptamine and tissue cyclic AMP formations. The soluble guanylate cyclase inhibitor methylene blue (10 microM) failed to block 5-hydroxytryptamine-induced relaxations. The results suggest that 5-hydroxytryptamine-induced relaxations of sheep pulmonary vein are mediated, at least in part, by increases of tissue cyclic AMP levels.
Zhang
L
L
Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine, Iowa State University, Ames 50011, USA.
Dyer
D C
DC
Fiscus
R R
RR
Grujic
Z
Z
Wang
X
X
D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D066298:In Vitro Techniques; D008751:Methylene Blue / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology; D011667:Pulmonary Veins / Q000187:drug effects* / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D012756:Sheep
D017366:Serotonin Receptor Agonists; D012701:Serotonin; D011189:Potassium Chloride; D000242:Cyclic AMP; D006162:Guanylate Cyclase; D008751:Methylene Blue