Intracellular signaling following myocardial stretch: an autocrine/paracrine loop.
The stretch of adult papillary muscle elicits a chain of autocrine/paracrine events in which the Na(+)/H(+) exchanger (NHE-1) activation is the central step. This activation is induced by a sequential angiotensin II-endothelin (Ang II-ET) release and results in an increase in intracellular Na(+) (Na(+)(i)) without significant changes in intracellular pH. The increase in Na(+)(i) negatively shifts the reverse potential of the Na(+)/Ca(2+) exchanger (NCX) thus inducing cell Ca(2+) influx that augments myocardial contractility. This increase in force represents the mechanical counterpart of the autocrine/paracrine mechanism triggered by stretch and has been called the slow force response (SFR) to stretch.
Cingolani
Horacio E
HE
Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina. cicmes@infovia.com.ar
Pérez
Néstor G
NG
Aiello
Ernesto A
EA
de Hurtado
María C Camilión
MC
D000804:Angiotensin II / Q000502:physiology; D000818:Animals; D016232:Endothelins / Q000502:physiology; D006321:Heart / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D010210:Papillary Muscles / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D012964:Sodium / Q000494:pharmacology
D016232:Endothelins; D000804:Angiotensin II; D012964:Sodium