The effects of diabetes on nitric oxide-mediated responses in rat corpus cavernosum.
Nitric oxide (NO)-mediated responses were investigated in corpora cavernosa isolated from 8-week diabetic rats. Relaxations to field stimulation were abolished by N(G)-nitro-L-arginine (NOARG, 100 microM). Responses to stimulation and sodium nitroprusside were reduced in tissues from diabetic rats compared to control rats, when data were expressed as g tension, but not when expressed as g/g tissue. The endothelium-dependent vasodilator, acetylcholine, failed to relax tissues. Stimulation-induced contractions were smaller in the diabetic group compared to the control group when data were expressed as g tension, but not g/g tissue. Contractions were enhanced by NOARG, and inhibited by acetylcholine (300 microM), by a similar degree in both groups. NOARG reduced the inhibitory effect of acetylcholine in tissues from control, but not diabetic rats. The results suggest diabetes caused a general impairment in responsiveness of rat corpus cavernosum, which may be a consequence of tissue weight change. A role for endothelium-dependent NO could not be identified; however, NO-mediated modulation of noradrenergic transmission by acetylcholine, may be defective in diabetes.
Way
K J
KJ
Department of Medical Laboratory Science, RMIT University, Melbourne, Victoria, Australia.
Reid
J J
JJ
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004558:Electric Stimulation; D004727:Endothelium / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation / Q000503:physiopathology; D009474:Neurons / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010413:Penis / Q000187:drug effects / Q000294:innervation / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D014665:Vasodilator Agents; D009599:Nitroprusside; D019335:Nitroarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D000109:Acetylcholine