title: L-arginine prevents impaired endothelium-dependent cerebral arteriolar dilatation during acute infusion of nicotine.
abstract: Exogenous treatment with L-arginine has been shown to restore impaired nitric oxide synthase (NOS)-dependent dilatation of peripheral blood vessels during disease states. We have shown that nicotine impairs NOS-dependent arteriolar dilatation in the cerebral circulation. However, the role of L-arginine in impaired responses of cerebral arterioles during infusion of nicotine has not been examined. Thus the goal of the present study was to examine the role of L-arginine in nicotine-induced impairment of cerebral arteriolar reactivity. We measured the diameter of pial arterioles in response to NOS-dependent (5'-adenosine diphosphate [ADP] and acetylcholine) and NOS-independent (nitroglycerin) agonists before and after infusion of vehicle or nicotine (2 microg/kg/min intravenously for 30 min followed by a maintenance dose of 0.35 microg/kg/min) in the absence or presence of L-arginine (10(-3) M). We found that topical application of L-arginine to cerebral microvessels during infusion of nicotine could prevent impaired NOS-dependent vasodilatation. We suggest that exogenous L-arginine may have a beneficial role in preventing cerebral microvascular dysfunction during exposure to nicotine.
authors.affiliation: Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA.
authors.forename: Qin
authors.initials: Q
authors.lastname: Fang
authors.forename: Hong
authors.initials: H
authors.lastname: Sun
authors.forename: William G
authors.initials: WG
authors.lastname: Mayhan
mesh_terms: D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D001160:Arterioles / Q000187:drug effects*; D001921:Brain / Q000098:blood supply* / Q000187:drug effects*; D004108:Dilatation, Pathologic / Q000209:etiology* / Q000517:prevention & control*; D004334:Drug Administration Schedule; D004730:Endothelium, Vascular / Q000187:drug effects*; D007262:Infusions, Intravenous; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000009:adverse effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D009538:Nicotine; D001120:Arginine; D019001:Nitric Oxide Synthase