Accelerated acetylcholine metabolism in the lung after infusion of phenylephrine in dogs.
We investigated whether continuous administration of an a-adrenergic agonist, phenylephrine, could affect acetylcholine metabolism within the pulmonary circulation in anesthetized dogs. Infusions of phenylephrine at 3 microg/kg/min for 120 min shifted the dose-response curve for the depressor responses produced by acetylcholine (0.03-10 micro g/kg) injected into the right atrium to the right by about 30-fold. In contrast, the magnitude of the rightward shift in the dose-response curve for the depressor responses produced by acetylcholine injected into the left ventricle was only 3-fold. These results suggest that continuous administration of alpha-adrenergic agonists accelerate acetylcholine metabolism within the pulmonary circulation.
Nakahara
Tsutomu
T
Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan. nakaharat@pharm.kitasato-u.ac.jp
Nejishima
Hiroaki
H
Nakayama
Koichi
K
Ishii
Kunio
K
D000109:Acetylcholine / Q000378:metabolism*; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D007262:Infusions, Intravenous; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010656:Phenylephrine / Q000008:administration & dosage / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D010656:Phenylephrine; D000109:Acetylcholine