Influence of the heme-oxygenase pathway on cerebrocortical blood flow.
Heme-oxygenase (HO)-derived carbon monoxide (CO) is generated in the cardiovascular and in the central nervous systems. Endogenous CO exerts direct vascular effects and has also been shown to inhibit nitric oxide synthase (NOS). In the current study, the heme-oxygenase blockade [zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG), 45 micromol/kg intraperitoneally] decreased cerebral CO production and increased cerebrocortical blood flow (CBF) in anesthetized rats. This latter effect was abrogated by the NOS blockade (50 mg/kg L-NAME intravenously). Furthermore, inhibition of CO production had no effect on stepwise hypoxia/hypercapnia-stimulated increases in CBF. Our results indicate that endogenous CO reduces the resting CBF via inhibition of NOS but fails to influence the CBF response to hypoxia and hypercapnia in adult rats.
Leszl-Ishiguro
Miriam
M
Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary.
Horváth
Béla
B
Johnson
Robert A
RA
Johnson
Fruzsina K
FK
Lenzsér
Gábor
G
Hermán
Péter
P
Horváth
Eszter M
EM
Benyó
Zoltán
Z
D000818:Animals; D002540:Cerebral Cortex / Q000098:blood supply* / Q000187:drug effects; D003905:Deuteroporphyrins / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D006935:Hypercapnia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D003905:Deuteroporphyrins; D004791:Enzyme Inhibitors; C060750:zinc deuteroporphyrin IX 2,4-bis(glycol); D006419:Heme Oxygenase (Decyclizing); D019331:NG-Nitroarginine Methyl Ester