Injected cyclic AMP increases ciliary beat frequency in conjunction with membrane hyperpolarization

Eur J Cell Biol. 1985 Mar;36(2):153-6.

Abstract

Injections of cyclic AMP (cAMP) and 8-Br-cAMP into Paramecium and external application of isobutylmethylxanthine (IBMX), an inhibitor of cAMP breakdown, to these cells increased the frequency of ciliary beating and hyperpolarized the membrane potential. When the membrane potential was held equal to the resting potential under voltage clamp, the same experimental conditions which serve to increase intracellular cAMP did not raise the ciliary frequency. We conclude that cAMP is presumably not the direct mediator of the hyperpolarization-induced ciliary activation, although it may be associated with this motor response.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 1-Methyl-3-isobutylxanthine / pharmacology
  • Animals
  • Cilia / drug effects*
  • Cilia / physiology
  • Cyclic AMP / pharmacology*
  • Membrane Potentials / drug effects
  • Movement
  • Paramecium / drug effects*
  • Paramecium / physiology

Substances

  • Cyclic AMP
  • 1-Methyl-3-isobutylxanthine