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KATP channel activation in a rabbit model of chronic myocardial hypoxia. J Mol Cell Cardiol 1997 Feb;29(2):845-8

Date

02/01/1997

Pubmed ID

9140841

DOI

10.1006/jmcc.1996.0361

Scopus ID

2-s2.0-0031064086   28 Citations

Abstract

Increased tolerance to ischemia exhibited in chronically hypoxia immature rabbit hearts is associated with increased activation of ATP-sensitive potassium (KATP) channels. We determined whether exposure to hypoxia from birth alters the electrophysiological characteristics of Purkinje fibers obtained from rabbits (n = 12/group) which were raised in a normoxic (F O2 = 0.21) or hypoxic (F1O2 = 0.12) environment from birth to 9 days of age and the involvement of the KATP channel. The endocardial surface was exposed and impaled with microelectrodes to record action potential characteristics from Purkinje fibers under control conditions and following exposure to glibenclamide (3 microM). Action potential durations (APD)90 in Purkinje fibers were significantly shorter in hypoxic hearts compared with normoxic controls (110 +/- 5 ms v 121 +/- 4 ms). Glibenclamide increased APD90 in hypoxic hearts (120 +/- 4 ms) to values similar to those observed in normoxic controls (121 +/- 4 ms). Glibenclamide had no effect on APD90 in normoxic hearts. Maximum diastolic potential was more negative in hypoxic hearts and this effect was attenuated by glibenclamide. We conclude that chronic myocardial hypoxia results in a shorter APD as compared with normoxic controls by enhanced activation of KATP channels.

Author List

Baker JE, Contney SJ, Gross GJ, Bosnjak ZJ

Authors

John E. Baker PhD Professor in the Surgery department at Medical College of Wisconsin
Zeljko J. Bosnjak PhD Professor in the Medicine department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Action Potentials
Adenosine Diphosphate
Adenosine Triphosphate
Animals
Animals, Newborn
Chronic Disease
Electrophysiology
Female
Glyburide
Heart
Hypoglycemic Agents
Hypoxia
Myocardium
Potassium Channels
Pregnancy
Purkinje Fibers
Rabbits
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a