Document Detail

Modulation of ATP-sensitive potassium channel activity by flash-photolysis of 'caged-ATP' in rat heart cells.
MedLine Citation:
PMID:  2315010     Owner:  NLM     Status:  MEDLINE    
We have used 'caged-ATP' to investigate the kinetic behavior of KATP channels in ventricular cells from rat heart. In whole cells, loaded with 'caged-ATP', an increase of intracellular [ATP] following a UV light flash produced a decrease of KATP channel current that was too slow (tau approximately 300 ms) to be explained by the expected time-course of ATP release (tau approximately 3 ms) and the time-course of channel blockade by ATP (tau approximately 20 ms). In isolated membrane patches, caged-ATP itself caused partial blockade of KATP) channels. Under these conditions, photorelease of ATP caused channel activity to decline further. The results suggest that caged-ATP can bind to the KATP) channel but, on binding, decreases the open probability to a lesser extent than does ATP. Additionally, the observations indicate that for photolytically-generated ATP to bind to the channel, caged-ATP must first unbind (slowly) from the channel. We conclude that 'caged-ATP' is not fully caged with respect to its allosteric action on the KATP channel.
C G Nichols; E Niggli; W J Lederer
Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Pflügers Archiv : European journal of physiology     Volume:  415     ISSN:  0031-6768     ISO Abbreviation:  Pflugers Arch.     Publication Date:  1990 Jan 
Date Detail:
Created Date:  1990-04-13     Completed Date:  1990-04-13     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0154720     Medline TA:  Pflugers Arch     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  510-2     Citation Subset:  IM    
Department of Physiology, University of Maryland, Baltimore 21201.
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MeSH Terms
Adenosine Triphosphate / analogs & derivatives*,  physiology*
Heart / physiology*
Heart Ventricles
Myocardium / cytology*
Potassium Channels / physiology*
Grant Support
Reg. No./Substance:
0/Potassium Channels; 56-65-5/Adenosine Triphosphate; 67030-27-7/P(3)-1-(2-nitro)phenylethyladenosine 5'-triphosphate

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