Short-term responses of coronary circulation to cortisol and estrogen in trout (Oncorhynchus mykiss).
This study was designed to investigate the short-term effects of cortisol and 17-beta-estradiol on the intact coronary tree of rainbow trout (Oncorhynchus mykiss). A non-working, isolated, and perfused heart preparation was used. The coronary pressure was monitored together with the coronary flow in order to calculate the coronary resistance. The drug effects were expressed as percent change in coronary resistance. At concentrations higher than 10(-5) mol l(-1), cortisol elicited a significant vasoconstriction (p<0.001) within 10 min of perfusion. The simultaneous administration of cortisol and adenosine (both at 10(-4) mol l(-1)) induced a significant reduction (p<0.001) of the coronary tree response elicited by each drug alone. The perfusion of the intact coronary trout system with 20 ng ml(-1) of 17-beta-estradiol elicited a significant vasodilative response (p<0.001) within 5-15 min of perfusion. This vasodilation did not involve nitric oxide, because no significant effect of Nomega-nitro-L-arginine (L-NA, a nitric oxide synthase inhibitor) in presence of the estrogen was observed. 17-beta-estradiol was also able to reduce the vasoconstriction induced by 10(-3) mol l(-1) acetylcholine. From these results it is possible to suggest that the steroid hormones, cortisol and 17-beta-estradiol, expound their action on the trout coronary tree through a non-genomic mechanism.
Agnisola
C
C
Dipartimento di Fisiologia Generale ed Ambientale, Università degli studi di Napoli Federico II, via Mezzocannone 8, 80134 Naples, Italy. agnisola@unina.it
Masullo
P
P
Mustafa
T
T
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects*; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006854:Hydrocortisone / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D019335:Nitroarginine / Q000494:pharmacology; D017686:Oncorhynchus mykiss / Q000502:physiology*; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D000893:Anti-Inflammatory Agents; D004791:Enzyme Inhibitors; D019335:Nitroarginine; D009569:Nitric Oxide; D004958:Estradiol; D006854:Hydrocortisone