Caffeine modulates potassium currents in Drosophila neurons

Int J Dev Neurosci. 2006 Jun;24(4):249-53. doi: 10.1016/j.ijdevneu.2006.03.002. Epub 2006 Apr 18.

Abstract

We investigated the effects of caffeine on the delayed-rectifier potassium current (IK(DR)) which is important in repolarizing the membrane potential, and the transient A-type potassium current (IK(A)) which regulates neuronal firing threshold and the rate of repetitive action potentials. The whole-cell patch-clamp technique was used to measure the currents from cultured Drosophila neurons derived from embryonic neuroblasts. The currents were measured from neurons before and after the application of 1mM caffeine to the external saline of the same neuron. IK(DR) measured in the caffeine-containing solution (470+/-36 pA, n=18), was smaller than that measured in the control 6K/0Ca Tris solution (745+/-51 pA, n=18). IK(A) measured in the caffeine-containing solution (17+/-2 pA, n=16) was smaller than that measured in the control 6K/0Ca Tris solution (35+/-4 pA, n=16). These results indicate that caffeine reduces IK(DR) and IK(A) amplitudes and possibly leads to increased action potential frequency and enhanced neuronal excitability.

Publication types

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

MeSH terms

  • Animals
  • Caffeine / pharmacology*
  • Cells, Cultured
  • Central Nervous System Stimulants / pharmacology*
  • Dose-Response Relationship, Radiation
  • Drosophila
  • Electric Stimulation / methods
  • Embryo, Nonmammalian
  • Membrane Potentials / drug effects
  • Membrane Potentials / radiation effects
  • Neurons / drug effects*
  • Neurons / metabolism
  • Patch-Clamp Techniques / methods
  • Potassium / pharmacology
  • Potassium Channels, Inwardly Rectifying / metabolism*

Substances

  • Central Nervous System Stimulants
  • Potassium Channels, Inwardly Rectifying
  • Caffeine
  • Potassium