Diabetes potentiates acetylcholine-induced relaxation in rabbit renal arteries

The response of rabbit renal arteries to acetylcholine and its endothelial modulation in diabetes were investigated. Acetylcholine induced concentrati on-related endothelium-dependent relaxation of renal arteries that was sign ificantly more potent in diabetic rabbits than in control rabbits. Pretreat ment with NG-nitro-L-arginine (L-NOArg), indomethacin, or L-NOArg plus indo methacin induced partial inhibition of acetylcholine-induced relaxation. In hibition induced by L-NOArg plus indomethacin was significantly higher in a rteries from diabetic rabbits than in arteries from control rabbits. In ren al arteries depolarised with KCl 30 mM and incubated with L-NOArg plus indo methacin, acetylcholine-induced relaxation was almost abolished in both gro ups of rabbits and this response was not different from that obtained in ar teries without endothelium. Sodium nitroprusside induced concentration-depe ndent relaxation of renal arteries from control and diabetic rabbits withou t significant differences between the two groups of animals. These results suggest that diabetes potentiates the acetylcholine-induced relaxation in r abbit renal arteries. Increased release of nitric oxide and prostacyclin co uld be responsible for the enhanced relaxant potency of acetylcholine in di abetes. (C) 2001 Elsevier Science B.V. All rights reserved.