Nitric oxide of neuronal origin mediates NMDA-induced cerebral hyperemia in rats.
The goal of this study was to determine whether neuronally derived nitric oxide mediates responses of cerebral blood flow (CBF) to N-methyl-D-aspartate (NMDA). In anesthetized Sprague-Dawley rats, regional CBF of the parietal cortex was monitored by laser-Doppler flowmetry. Topical application of either NMDA or acetylcholine produced concentration-related increases in CBF. Responses of CBF to NMDA (10(-5) M) but not to acetylcholine were inhibited (0+/-3% vs 21+/-5%, p < 0.05) by 7-nitroindazole (50 mg/kg, i.p.). MK-801 (0.5 mg/kg, i.v.) and tetrodotoxin (10(-6) M, topical application) also inhibited NMDA-induced responses. These results suggest that nitric oxide of neuronal origin mediates NMDA-induced increases in CBF.
Yang
S T
ST
Department of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan, R.O.C.
Chang
H H
HH
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006940:Hyperemia / Q000139:chemically induced*; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects*; D009569:Nitric Oxide / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013779:Tetrodotoxin / Q000494:pharmacology
D018691:Excitatory Amino Acid Antagonists; D009569:Nitric Oxide; D013779:Tetrodotoxin; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D000109:Acetylcholine