Voltage-activated Ca2+ currents in insulin-secreting cells

FEBS Lett. 1985 Sep 23;189(2):281-5. doi: 10.1016/0014-5793(85)81040-1.


Membrane voltage and voltage-clamped membrane currents have been investigated with the whole-cell patch clamp method in the insulin-secreting cell line RINm5F. The mean resting membrane potential of RINm5F cells was found to be -52 mV. Overshooting spike potentials could be evoked by depolarising voltage steps in the absence of a secretagogue. Inward membrane currents evoked by depolarising voltage steps were dependent upon extracellular Ca2+ and blocked by Co2+, nifedipine and verapamil. Outward membrane currents which were evoked by depolarising voltage steps to positive membrane potentials were reduced when Ca2+ entry was prevented. It is concluded that the voltage-activated Ca2+ currents underlie the voltage-activated spike potentials recorded from insulin-secreting cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Cell Line
  • Cobalt / pharmacology
  • Egtazic Acid / pharmacology
  • Electric Conductivity
  • Evoked Potentials
  • Insulin / metabolism*
  • Insulin Secretion
  • Ion Channels / metabolism*
  • Membrane Potentials
  • Nifedipine / pharmacology
  • Verapamil / pharmacology


  • Insulin
  • Ion Channels
  • Cobalt
  • Egtazic Acid
  • Verapamil
  • Nifedipine
  • Calcium