Neuronal NO promotes cerebral cortical hyperemia during cortical spreading depression in rabbits.
Temporary elevations in cortical cerebral blood flow (CBF) accompany cortical spreading depression (CSD) in anesthetized animals. We tested the hypothesis that nitric oxide (NO) is an important promotor of CSD-induced cortical hyperemia in urethan-anesthetized rabbits. CBF was measured at four time points by administration of 15-microm microspheres with the reference withdrawal technique. Intravenous administration of the nonspecific NO synthase (NOS) inhibitor N(omega)-nitro-L-arginine increased mean arterial blood pressure and resting cerebrovascular resistance and attenuated CSD-induced hyperemia. Cortical CBF before intraperitoneal 7-nitroindazole (7-NI), a neuronal NOS inhibitor, was 42 +/- 8 and 124 +/- 19 ml x 100 g(-1) x min(-1) at baseline and during CSD, respectively (P < 0.05 by repeated-measures analysis of variance). After 7-NI administration, mean arterial blood pressure, CBF, and cerebrovascular resistance were unchanged from baseline values; cortical CBF was 38 +/- 4 and 90 +/- 8 ml x 100 g(-1) x min(-1) post-7-NI at rest and during a second CSD, respectively. Similar to N(omega)-nitro-L-arginine, 7-NI decreased the cortical hyperemic response during CSD (P < 0.05 by repeated-measures analysis of variance). We conclude that neuronal NOS promotes the temporary cortical hyperemia observed during CSD.
Colonna
D M
DM
Department of Anesthesia, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157-1009, USA.
Meng
W
W
Deal
D D
DD
Gowda
M
M
Busija
D W
DW
D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000098:blood supply*; D002245:Carbon Dioxide / Q000097:blood; D002540:Cerebral Cortex / Q000098:blood supply* / Q000502:physiology / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D013181:Cortical Spreading Depression; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006940:Hyperemia / Q000503:physiopathology*; D008863:Microspheres; D009474:Neurons / Q000502:physiology*; D009569:Nitric Oxide / Q000502:physiology*; D019335:Nitroarginine / Q000494:pharmacology*; D009928:Organ Specificity; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011817:Rabbits; D012039:Regional Blood Flow; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects
D006454:Hemoglobins; D002245:Carbon Dioxide; D019335:Nitroarginine; D009569:Nitric Oxide; D010100:Oxygen