The cerebrocortical microcirculatory effect of nitric oxide synthase blockade is dependent upon baseline red blood cell flow in the rat.
The effects of nitric oxide synthase (NOS) blockade on the cerebrocortical microcirculation were investigated under physiological conditions in anesthetized ventilated rats using laser-Doppler (LD) flowmetry. LD flow values of the parietal cortex were determined before and after systemic administration of the NOS inhibitor N(G)-nitro-L-arginine-methyl-esther. NOS blockade reduced the LD flow significantly and the magnitude of the reduction was in close correlation with the baseline value. Synchronized sinus-wave-like LD flow oscillations were observed frequently after NOS inhibition and their appearance was also dependent on the high baseline flow values. These results indicate marked, baseline-dependent differences in the cerebrocortical blood flow response to the inhibition of the nitric oxide pathway, and may suggest that areas with high resting red blood cell flow express high NOS activity.
Lacza
Z
Z
Clinical Research Department - 2nd Institute of Physiology, Semmelweis University, Ulloi út 78/a, H-1082, Budapest, Hungary.
Erdos
B
B
Görlach
C
C
Wahl
M
M
Sándor
P
P
Benyó
Z
Z
D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D002540:Cerebral Cortex / Q000098:blood supply* / Q000201:enzymology* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology / Q000378:metabolism / Q000502:physiology; D008297:Male; D008833:Microcirculation / Q000201:enzymology / Q000294:innervation; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000502:physiology; D052248:Nitric Oxide Synthase Type I; D051381:Rats; D017208:Rats, Wistar
D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat; D019331:NG-Nitroarginine Methyl Ester