DIRECT MYOCARDIAL DEPRESSION EFFECTS OF INHALATIONAL ANESTHETICS IN CULTURED RAT CARDIAC MYOCYTES

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 06671545
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Anesthesiology/Resuscitation studies
• Research Institution: SAPPORO MEDICAL UNIVERSITY
• Principal Investigator: MATSUMOTO Maki SAPPOR MEDICAL UNIVERSITY SCHOOL OF MEDICINE.ASSOCIATE PROFESSOR, 医学部, 講師 (00173914)
• Co-Investigator(Kenkyū-buntansha): MIYAMOTO Atsushi SAPPORO MEDICAL UNIVERSITY SCHOOL OF MEDICINE,ASSISTANT PROFESSOR, 医学部, 助教授 (50166196) ; KIMURA Hisakazu SAPPORO MEDICAL UNIVERSITY SCHOOL OF MEDICINE,DOCTORALFELLOW, 医学部, 助手 (20204985) ; KANAYA Noriaki SAPPORO MEDICAL UNIVERSITY SCHOOL OF MEDICINE,DOCTORALFELLOW, 医学部, 助手 (10244344)
• Project Period (FY): 1994 – 1996
• Keywords: ANESTHETICS / HEART / CARDIAC MYOCYTES / CARDIAC FUNCTIONS / CALCIUM CHANNEL

Research Abstract

Inhalational anesthetics are widely used because they can easily bring a stable depth of anesthesia without any serious complications. However suppression of cardiovascular system is not rare. The cause of this depression is believed to be delivered by the cardiac suppressive effect by inhalational anesthetics. It is difficult to delete the effects of the vascular, neurogenic, and hormonal effects in vivo experiments. Experiments using cultured cardiac myocytes cane eliminate those effects seen in vivo studies, and thefore it can make clear the direct cardiac suppressive effects of anesthetics in a relatively independent conditions.
The purpose of this study are the followings ; 1) The effects of phosphodiesterase inhibitor (amrinone), Ca^<2+> sensitize (pimobendan) on the myocardial depression effect by halothane, 2) The effects of KATP channel opener (cromakalim), blocker (glibenclamide) on the myocardial depression effects of halothane, 3) The effect of halothane on L-type Ca^<2+> channel binding, 4) The effects of L-type Ca^<2+> channel agonist (Bay K 8644) on myocardial depression effect by various inhalational anesthetics in cultured rat cardiac myocytes.
In results, some inhalational anesthetics showed cardiac depressive effects in a concentration-dependent manner, and those effects are prominent in halothane>isoflurane>sevoflurane. Those myocardial depression effects are supposed to have a relations with a suppression of L-type Ca^<2+> channel. Moreover, the myocardial depression effects of halothane is not related to lowering of intracellular cyclic AMP concentration, lowering of sensitivity to Ca^<2+> of contraction proteins, nor KATP channel.