title: Mechanical effects on KATP channel gating in rat ventricular myocytes.
abstract: Cardiac KATP channels link metabolism with electrical activity. They are implicated in arrhythmias, secretion of atrial natriuretic peptide and protection of the heart from hypertrophy and failure. These processes may involve mechanosensitivity. KATP channels can be activated by mechanical stimulation and disrupting the cortical actin increases the activity. We propose that KATP channels are modulated by local bilayer tension and this tension is affected by cortical F-actin. Here we measured KATP background activity and stretch sensitivity with inside-out patches of rat ventricular myocytes before and after disrupting F-actin. Disrupting F-actin potentiated background activity but did not influence the slope sensitivity in the semilog relationship of NPo vs. suction that is a measure of the change in dimensions between closed and open states. Thus actin alters prestress on the channel probably by parallel elastic sharing of mean cortical tension with the bilayer.
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China.
authors.forename: Haixia
authors.initials: H
authors.lastname: Huang
authors.forename: Lifang
authors.initials: L
authors.lastname: Liang
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Hua
authors.initials: H
authors.lastname: Wei
authors.forename: Frederick
authors.initials: F
authors.lastname: Sachs
authors.forename: Weizhen
authors.initials: W
authors.lastname: Niu
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena; D003571:Cytochalasin B / Q000494:pharmacology; D005260:Female; D006352:Heart Ventricles / Q000166:cytology*; D015640:Ion Channel Gating / Q000187:drug effects; D054086:KATP Channels / Q000378:metabolism*; D055595:Mechanical Phenomena; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013947:Thymosin / Q000494:pharmacology; D000099201:Thymosin beta(4)
chemical_list: D000199:Actins; D003571:Cytochalasin B; D054086:KATP Channels; D013947:Thymosin; D000099201:Thymosin beta(4)