Competitive inhibition of nitric oxide synthase prevents the cortical hyperemia associated with peripheral nerve stimulation.
With combined microdialysis and hydrogen clearance techniques for simultaneous local delivery of drugs and blood-flow measurement in the rat hindlimb sensory-motor cortex, we examined the role of nitric oxide in cerebral blood-flow regulation during sciatic nerve stimulation. Infusion of 1 mM nitric oxide synthase antagonist, N eta-nitro-L-arginine methyl ester (L-NAME), blocked the cortical blood-flow response to sciatic nerve stimulation (152 +/- 43 ml.min-1.100 g-1 of tissue in controls and 73 +/- 11 ml.min-1.100 g-1 in the presence of L-NAME; P less than 0.05). Addition of 10 mM L-arginine to the dialysate containing L-NAME partially restored the hyperemic response to nerve stimulation (125 ml.min-1.100 g-1). L-NAME also produced a decrease in baseline cerebral blood flow when compared with the control (66 +/- 14 ml.min-1.100 g-1 vs. 93 +/- 25 ml.min-1.100 g-1). We conclude that nitric oxide from activated neurons participates in the local regulation of cortical blood flow in response to sciatic nerve stimulation and also in the maintenance of basal cortical blood flow.
Northington
F J
FJ
University of Virginia Health Sciences Center, Department of Physiology, Charlottesville 22908.
Matherne
G P
GP
Berne
R M
RM
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002540:Cerebral Cortex / Q000098:blood supply*; D002560:Cerebrovascular Circulation; D004558:Electric Stimulation; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D019001:Nitric Oxide Synthase; D010525:Peripheral Nerves / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D019331:NG-Nitroarginine Methyl Ester