Regulation of common carotid arterial blood flow by nitrergic neurons in the medulla of cats.
Glutamate stimulation of the dorsal facial area, an area located dorsal to the facial nucleus, increases common carotid arterial blood flow. Nitrergic neurons are important in cardiovascular regulatory areas. We investigated whether the nitrergic neurons might be present and play a role in the dorsal facial area to regulate the arterial blood flow. Injections of L-arginine (an NO precursor) and sodium nitroprusside (an NO donor) into the area caused dose-dependent increases in the arterial blood flow. Injection of N(G)-nitro-arginine methyl ester (L-NAME, an NO synthase inhibitor) or methylene blue (a guanylate cyclase inhibitor) decreased the arterial blood flow. Nitrergic neurons and fibers were found in the dorsal facial area by histochemical staining of nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase, a maker of NO synthase. In conclusion, nitrergic neurons are present in the dorsal facial area and appear to release NO tonically in stimulating the area to cause increase in common carotid arterial blood flow.
Gong
Chi-Li
CL
Department of Physiology, School of Medicine, China Medical University, Taichung, Taiwan, ROC.
Chiu
Yung-Tsung
YT
Lin
Nai-Nu
NN
Cheng
Ching-Chang
CC
Li
Hsing-Tan
HT
Kuo
Jon-Son
JS
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D017536:Carotid Artery, Common / Q000502:physiology*; D002415:Cats; D005260:Female; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology / Q000502:physiology*; D008845:Microinjections; D009249:NADP / Q000378:metabolism; D009252:NADPH Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D026602:Nitrergic Neurons / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D012039:Regional Blood Flow
D020030:Nitric Oxide Donors; D009599:Nitroprusside; D009569:Nitric Oxide; D009249:NADP; D001120:Arginine; D009252:NADPH Dehydrogenase; D019331:NG-Nitroarginine Methyl Ester