L-arginine-induced dilatation of goat coronary artery involves activation of K(ATP) channels.
In the present study, the mechanism of relaxant response of nitric oxide precursor, L-arginine, was investigated in goat isolated coronary artery. L-arginine (1 mM) reversed the U-46619 (1 microM)-induced contraction both in endothelium-intact and endothelium-denuded arterial ring preparations. L-arginine analogues, L-NAME, L-NNA and L-NMMA and the guanylyl cyclase inhibitor, methylene blue failed to attenuate the relaxant response of L-arginine. These observations negate the involvement of nitric oxide in mediating the relaxation by L-arginine. K(ATP) channel blocker, glibenclamide (3 microM), abolished the vasorelaxant responses of L-arginine in endothelium-denuded preparations, thereby suggesting the involvement of KATP channels. Further, L-arginine also failed to induce relaxation of the coronary arterial rings constricted with K+ (80 mM)-PSS. Taken together, the results of the present study suggest that L- arginine relaxes goat isolated coronary artery through activation of K(ATP) channels.
Deka
Dilip K
DK
Department of Pharmacology & Toxicology, AAU, Khanapara, Guwahati-781022, India. drdilipdeka@rediffmail.com
Mishra
Santosh K
SK
Raviprakash
Vellanki
V
D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D003331:Coronary Vessels / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D006041:Goats; D007004:Hypoglycemic Agents / Q000494:pharmacology; D054086:KATP Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008751:Methylene Blue / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D007004:Hypoglycemic Agents; D054086:KATP Channels; D014665:Vasodilator Agents; D001120:Arginine; D013755:Tetradecanoylphorbol Acetate; D005905:Glyburide; D008751:Methylene Blue