Developmental Change in the Voltage-Dependence of the Pacemaker Current, If, in Rat Ventricle Cells

Pflugers Arch. 1997 Feb;433(4):533-5. doi: 10.1007/s004240050309.


Myocytes were isolated from newborn and adult rat ventricle. Using the whole-cell patch clamp, the two cell populations were compared for the presence of the hyperpolarization-activated pacemaker current if. As in other mammalian species, the threshold voltage in acutely dissociated adult rat myocytes was extremely negative (-113 +/- 5 mV; n=12). In contrast, threshold in newborn cells was relatively positive, regardless of whether measured in acutely dissociated (-72 +/- 2 mV; n=6) or cultured cells (-70 +/- 2 mV; n=9). Current density was not reduced in the adult. These results suggest that with development the ventricle assumes its non-pacemaker function, at least in part, by a shift of the voltage dependence of if outside the physiological range.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Animals, Newborn / growth & development*
  • Biological Clocks / physiology*
  • Patch-Clamp Techniques
  • Rats
  • Ventricular Function*