Nicotine-induced NO-mediated increase in cortical cerebral blood flow is blocked by beta2-adrenoceptor antagonists in the anesthetized rats.
Involvement of nitric oxide (NO) and beta-adrenoceptors in an increase in the cortical cerebral blood flow (CBF) following an intravenous (i.v.) injection of a small dose of nicotine which did not affect the systemic blood pressure in the rats was investigated. I.v. injection of nicotine (30 microg/kg) for 1 min produced a significant increase in CBF lasting for more than 20 min without a significant effect on the systemic blood pressure. I.v. injection of L-N(G)-nitroarginine methylester (30 mg/kg) significantly attenuated nicotine-induced increase in the cortical CBF. The attenuation was reversed by i.v. injection of L-arginine (300 mg/kg), suggesting an intimate role of nitric oxide (NO) in nicotine-induced increase in the cortical CBF. The nicotine-induced increase in the cortical CBF was significantly attenuated by propranolol (10 mg/kg, i.v.) and ICI 118,551 (a beta2-adrenoceptor antagonist, 10 mg/kg, i.v.) but not by metoprolol (a beta1-adrenoceptor antagonist, 10 mg/kg, i.v.). Beta2-adrenoceptors on presynaptic nitrergic nerves may be involved in nicotine-induced NO-mediated increase in the cortical CBF.
Uchida
Sae
S
Department of the Autonomic Nervous System, Tokyo Metropolitan Institute of Gerontology, Itabashi, Japan. suchida@center.tmig.or.jp
Kawashima
Koichiro
K
Lee
Tony J F
TJ
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar
D000319:Adrenergic beta-Antagonists; D004791:Enzyme Inhibitors; D018722:Nicotinic Agonists; D009569:Nitric Oxide; D009538:Nicotine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester