Nitric oxide synthase inhibitor blocks acetylcholine induced increase in brain blood flow in rainbow trout.
Nitric oxide (NO) dependent regulation of blood flow has hitherto not been demonstrated in rainbow trout or other salmonid fish. Through in vivo observations of the brain surface (optic lobes) of rainbow trout (Oncorhynchus mykiss) with epi-illumination microscopy, we show that application of acetylcholine (ACh) to the brain surface induces an increase in cerebral blood flow velocity that can be completely blocked by the NO synthase inhibitor NG-nitro-L-arginine. Also sodium nitroprusside, which decomposes to form NO, stimulated cerebral blood flow velocity. The results indicate that NO is a vasodilator in rainbow trout brain, mediating the effect of ACh.
Söderström
V
V
Department of Limnology, Uppsala University, Sweden.
Hylland
P
P
Nilsson
G E
GE
D000109:Acetylcholine / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001783:Blood Flow Velocity / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D019335:Nitroarginine; D009599:Nitroprusside / Q000494:pharmacology; D017686:Oncorhynchus mykiss
D009599:Nitroprusside; D019335:Nitroarginine; D001120:Arginine; D019001:Nitric Oxide Synthase; D000109:Acetylcholine