Stretch activated ion channels in ventricular myocytes.
Patch-clamp recordings from ventricular myocytes of neonatal rats identified ionic channels that open in response to membrane stretch caused by negative pressures (1 to 6 cm Hg) in the electrode. The stretch response, consisting of markedly increased channel opening frequency, was maintained, with some variability, during long (greater than 40 seconds) stretch applications. The channels have a conductance averaging 120pS in isotonic KCl, have a mean reversal potential 31 mV depolarized from resting membrane potential, and do not require external Ca++ for activation. The channels appear to be relatively non-selective for cations. Since they are gated by physiological levels of tension, stretch-activated channels may represent a cellular control system wherein beat-to-beat tension and/or osmotic balance modulate a portion of membrane conductance.
Craelius
W
W
Department of Cardiology, State University of New York, Brooklyn 11209.
Chen
V
V
el-Sherif
N
N
D000818:Animals; D015220:Calcium Channels / Q000032:analysis*; D006352:Heart Ventricles / Q000032:analysis; D066298:In Vitro Techniques; D008465:Mechanoreceptors / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism*; D015221:Potassium Channels / Q000032:analysis*; D051381:Rats; D014672:Vectorcardiography / Q000379:methods
D015220:Calcium Channels; D015221:Potassium Channels