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Titolo:
CHARACTERIZATION OF ACETYLCHOLINESTERASE IN RABBIT INTRAPULMONARY ARTERIES
Autore:
ALTIERE RJ; TRAVIS DC; THOMPSON DC;
Indirizzi:
UNIV COLORADO,HLTH SCI CTR,SCH PHARM,4200 E 9TH AVE,BOX C-238 DENVER CO 80206
Titolo Testata:
American journal of physiology. Lung cellular and molecular physiology
fascicolo: 6, volume: 11, anno: 1994,
pagine: 120000745 - 120000752
SICI:
1040-0605(1994)11:6<120000745:COAIRI>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
NITRO-L-ARGININE; PULMONARY-ARTERIES; IMMUNE-SENSITIZATION; INNERVATION; RESPONSES; MICROVESSELS; VASODILATION; CIRCULATION; ENTEROCYTES; INHIBITION;
Keywords:
ENZYME KINETICS; ACETYLCHOLINE; NEOSTIGMINE; VASOCONSTRICTION; VASORELAXATION; PULMONARY VASCULATURE; PULMONARY ARTERIES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
R.J. Altiere et al., "CHARACTERIZATION OF ACETYLCHOLINESTERASE IN RABBIT INTRAPULMONARY ARTERIES", American journal of physiology. Lung cellular and molecular physiology, 11(6), 1994, pp. 120000745-120000752

Abstract

Acetylcholine (ACh) acts on the pulmonary vasculature to evoke vasodilation and, in some species, vasoconstriction. The actions of ACh are terminated by its rapid hydrolysis by cholinesterases. Aside from histochemical localization studies, there is little information on cholinesterase enzymes in pulmonary blood vessels. The present study addresses the hypothesis that pulmonary blood vessels contain sufficient cholinesterase activity to regulate the action of ACh in these tissues. Accordingly, studies were undertaken to characterize and quantify cholinesterase activities in pulmonary arteries and veins, quantify inhibition of enzyme activity, and investigate functional physiological consequences of cholinesterase inhibition. Cholinesterase activities in aortaand trachea also were examined for comparison. Kinetic studies showedthat the lobar pulmonary arterial enzyme has a Michaelis constant of 55.3 +/- 17.0 mu M and a maximum velocity of 8.6 +/- 2.7 nmol/min/mg protein similar to cholinesterases found in other peripheral tissues. Studies with selective inhibitors revealed that >98% of total enzyme activity was attributable to acetylcholinesterase. Similar levels of enzyme activity were found in homogenates of lobar branch intrapulmonary arteries, intrapulmonary veins, and aorta. The majority of enzyme activity was localized to the membrane fraction, although a moderate amount was found in the cytosol. Studies in intact intrapulmonary lobar arteries showed that these vessels had cholinesterase activity comparablewith that found in intact trachealis muscle and that neostigmine (10 nM to 10 mu M) caused concentration-dependent inhibition of enzyme activity. In isolated intrapulmonary lobar arteries, functional studies showed that 1 and 10 mu M neostigmine significantly potentiated ACh-induced contractions. Enzyme inhibition also potentiated contractile responses in the smaller intrapulmonary lobar branch arteries but not relaxant responses in intrapulmonary lobar arteries. The findings demonstrate that intrapulmonary arteries contain sufficient acetylcholinesterase activity to rapidly degrade ACh and regulate its contractile actions in the pulmonary vasculature.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 07:01:59