ATP-sensitive potassium channel mediates delayed ischemic protection by heat stress in rabbit heart.
Publication/Presentation Date
11-1-1997
Abstract
Heat shock protects against myocardial ischemia-reperfusion injury possibly via increased expression of heat shock proteins. The direct evidence of heat shock protein protection in vivo remains circumstantial, and no other new mechanism of protection has been proposed. Recent studies suggest that opening of ATP-sensitive K+ channels (KATP channels) plays an important role in ischemic preconditioning; however, it is not known whether this channel is also important in delayed protection conferred by heat shock. Anesthetized rabbits underwent heat shock treatment by raising core temperature to 42 degrees C for 15 min. Twenty-four hours later, the animals were reanesthetized and subjected to regional ischemia-reperfusion. The specific KATP channel blockers glibenclamide (0.3 mg/kg i.p.) and sodium 5-hydroxydecanoate (5HD; 5 mg/kg i.v.) were used to block the channel function. The drugs were administered at two different times, either pre-heat stress or preischemia. Infarct size was determined by triphenyltetrazolium chloride staining. The 72-kDa heat shock protein (HSP 72) was measured by Western blots. Our results show that heat shock produced a marked reduction in infarct size (39.4 +/- 8.1 to 14.3 +/- 2.5% of risk area, P < 0.05). Glibenclamide and 5HD completely abolished heat shock-induced reduction in infarct size (42.3 +/- 0.32 and 33.7 +/- 4.8%) when given before ischemia-reperfusion; however, these antagonists failed to block protection when administered before the onset of heat shock. Furthermore, the enhanced expression of HSP 72 in heat shock groups was not diminished by glibenclamide or 5HD, suggesting a lack of a direct role of this protein in conferring cardiac protection by heat shock. The complete blockade of cardiac protection by glibenclamide and 5HD strongly suggests that opening of this channel is a very important component of heat shock-induced ischemic protection in rabbit hearts.
Volume
273
Issue
5
First Page
2458
Last Page
2464
ISSN
0002-9513
Published In/Presented At
Hoag, J. B., Qian, Y. Z., Nayeem, M. A., D'Angelo, M., & Kukreja, R. C. (1997). ATP-sensitive potassium channel mediates delayed ischemic protection by heat stress in rabbit heart. The American journal of physiology, 273(5), H2458–H2464. https://doi.org/10.1152/ajpheart.1997.273.5.H2458
Disciplines
Medicine and Health Sciences
PubMedID
9374785
Department(s)
Department of Medicine
Document Type
Article