Role of nitric oxide in gastric hyperemia induced by central vagal stimulation.
The effects of N omega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthesis, on the vagal cholinergic increase in gastric mucosal blood flow (GMBF) and acid secretion induced by intracisternal injection of the thyrotropin-releasing hormone (TRH) analogue, RX 77368, were studied. GMBF and acid secretion were measured simultaneously by the hydrogen gas clearance technique and titration of gastric perfusate in urethan-anesthetized rats. RX 77368 (30 ng) injected intracisternally stimulated gastric acid secretion and GMBF for 90 and 180 min respectively. GMBF was increased from basal 63 +/- 4 to 166 +/- 14 ml.min-1.100 g-1 at 60 min postinjection. L-NAME (3 mg/kg) injected intravenously 15 min before RX 77368 completely prevented the increase in GMBF induced by the TRH analogue, whereas the acid response was not modified. The effect of L-NAME was reversed by L-arginine but not by the stereoisomer D-arginine. These results show that the increase in GMBF, but not the stimulation of acid secretion, induced by central vagal activation is mediated through a product of L-arginine-NO pathway.
Tanaka
T
T
Center for Ulcer Research and Education, Veterans Affairs Medical Center, Los Angeles, California.
Guth
P
P
Taché
Y
Y
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001921:Brain / Q000502:physiology*; D005744:Gastric Acid / Q000378:metabolism; D006940:Hyperemia / Q000209:etiology*; D007276:Injections, Intraventricular; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000378:metabolism*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D013237:Stereoisomerism; D013270:Stomach / Q000098:blood supply*; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D014630:Vagus Nerve / Q000502:physiology*
D009569:Nitric Oxide; D013973:Thyrotropin-Releasing Hormone; C027979:L-pyroglutamyl-L-histidyl-3,3-dimethylprolinamide; D001120:Arginine; D011761:Pyrrolidonecarboxylic Acid; D019331:NG-Nitroarginine Methyl Ester