title: Stretch-activated whole cell currents in adult rat cardiac myocytes.
abstract: Mechanoelectric transduction can initiate cardiac arrhythmias. To examine the origins of this effect at the cellular level, we made whole cell voltage-clamp recordings from acutely isolated rat ventricular myocytes under controlled strain. Longitudinal stretch elicited noninactivating inward cationic currents that increased the action potential duration. These stretch-activated currents could be blocked by 100 microM Gd(3+) but not by octanol. The current-voltage relationship was nearly linear, with a reversal potential of approximately -6 mV in normal Tyrode solution. Current density varied with sarcomere length (SL) according to I (pA/pF) = 8.3 - 5.0 SL (microm). Repeated attempts to record single channel currents from stretch-activated ion channels failed, in accord with the absence of such data from the literature. The inability to record single channel currents may be a result of channels being located on internal membranes such as the T tubules or, possibly, inactivation of the channels by the mechanics of patch formation.
authors.affiliation: Department of Physiology and Biophysics, State University of New York, Buffalo, New York 14214, USA.
authors.forename: T
authors.initials: T
authors.lastname: Zeng
authors.forename: G C
authors.initials: GC
authors.lastname: Bett
authors.forename: F
authors.initials: F
authors.lastname: Sachs
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000375:Aging / Q000502:physiology*; D000818:Animals; D004553:Electric Conductivity; D006321:Heart / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D008955:Models, Cardiovascular; D009206:Myocardium / Q000166:cytology; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D012518:Sarcomeres / Q000502:physiology / Q000648:ultrastructure; D012964:Sodium / Q000502:physiology
chemical_list: D012964:Sodium