Differential effects of halothane, enflurane, and isoflurane on Ca2+ transients and papillary muscle tension in guinea pigs. Anesthesiology 1992 Jan;76(1):123-31
Date
01/01/1992Pubmed ID
1729916DOI
10.1097/00000542-199201000-00018Scopus ID
2-s2.0-0026501956 (requires institutional sign-in at Scopus site) 60 CitationsAbstract
These studies were designed to examine the effects of inhalational anesthetics on rapid changes in myocardial intracellular Ca2+ and Ca2+ sensitivity of the contractile apparatus. The effects of halothane, enflurane, and isoflurane on rapid changes in intracellular Ca2+ (Ca2+ transients as measured with bioluminescent protein aequorin) and contractile characteristics were compared in guinea pig right ventricular papillary muscles. In addition to examination of their potencies at equianesthetic concentrations, the effects of these agents on alterations in Ca2+ sensitivity at myofilaments were also investigated. The negative inotropic effects of halothane (0.65 and 1.15%) and enflurane (1.0 and 2.2%) were dose-dependent and closely related to a decrease in Ca2+ transients. In the presence of isoflurane (0.77 and 1.6%), the contractile force decreased in a dose-dependent manner, but the decrease was significantly less as compared to that with equianesthetic concentrations of halothane and enflurane. An additional feature observed in the presence of isoflurane was a dissociation between intracellular Ca2+ availability and contractile force. Although the magnitude of the Ca2+ transients did not change when the percentage of isoflurane was increased from 0.77 to 1.6, the contractile force decreased. Because of these findings, the effects of halothane (1.2%), enflurane (2.2%), and isoflurane (1.6%) on the relationship between intracellular Ca2+ and tension developed in the papillary muscle were examined in order to assess myofibrillar responsiveness to Ca2+. The results indicate that only isoflurane slightly but significantly shifted the Ca2+/isometric tension curve toward higher intracellular Ca2+ concentrations; no differences were observed in the absence and presence of equianesthetic concentrations of halothane and enflurane.(ABSTRACT TRUNCATED AT 250 WORDS)
Author List
Bosnjak ZJ, Aggarwal A, Turner LA, Kampine JM, Kampine JPMESH terms used to index this publication - Major topics in bold
AnimalsCalcium
Dose-Response Relationship, Drug
Enflurane
Guinea Pigs
Halothane
Isoflurane
Isometric Contraction
Myocardial Contraction
Papillary Muscles
Sarcoplasmic Reticulum
Troponin
Troponin C
