Inhalation anaesthetics decrease calcium content of cardiac sarcoplasmic reticulum.
In a Langendorff perfused rat heart model, caffeine was shown to have a negative inotropic effect similar to that of inhalation anaesthetics. Both inhalation anaesthetics and caffeine decreased calcium content of left ventricular muscle as measured by atomic absorption spectroscopy. Halothane 2.8% decreased left ventricular pressure by 75.4 (SEM 4.4)% and decreased the calcium content by 30%. Enflurane 5.1% decreased the pressure by 72.4 (6.0)% and decreased calcium content by 31%. Both halothane and enflurane decreased the calcium content of sarcoplasmic reticulum (SR) as measured by caffeine-induced calcium release. There was a high degree of correlation between the negative inotropic effect of inhalation anaesthetics and the decrease in calcium content of the SR (r = 0.95 for halothane, r = 0.91 for enflurane). These data suggest that inhalation anaesthetics increase the calcium permeability of cardiac SR, thereby decreasing the calcium content of SR, resulting in the negative inotropic effect.
Katsuoka
M
M
Membrane Research Institute, University City Science Center, Philadelphia, PA 19104.
Ohnishi
S T
ST
D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D004737:Enflurane / Q000494:pharmacology; D006221:Halothane / Q000494:pharmacology; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D010210:Papillary Muscles / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D012519:Sarcoplasmic Reticulum / Q000187:drug effects* / Q000378:metabolism
D000777:Anesthetics; D002110:Caffeine; D004737:Enflurane; D002118:Calcium; D006221:Halothane