Activity-independent homeostasis in rhythmically active neurons

Neuron. 2003 Jan 9;37(1):109-20. doi: 10.1016/s0896-6273(02)01104-2.


The shal gene encodes the transient potassium current (I(A)) in neurons of the lobster stomatogastric ganglion. Overexpression of Shal by RNA injection into neurons produces a large increase in I(A), but surprisingly little change in the neuron's firing properties. Accompanying the increase in I(A) is a dramatic and linearly correlated increase in the hyperpolarization-activated inward current (I(h)). The enhanced I(h) electrophysiologically compensates for the enhanced I(A), since pharmacological blockade of I(h) uncovers the physiological effects of the increased I(A). Expression of a nonfunctional mutant Shal also induces a large increase in I(h), demonstrating a novel activity-independent coupling between the Shal protein and I(h) enhancement. Since I(A) and I(h) influence neuronal activity in opposite directions, our results suggest a selective coregulation of these channels as a mechanism for constraining cell activity within appropriate physiological parameters.

Publication types

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

MeSH terms

  • Action Potentials / genetics*
  • Animals
  • Biological Clocks / genetics
  • Electric Stimulation
  • Female
  • Ganglia, Invertebrate / cytology
  • Ganglia, Invertebrate / physiology*
  • Homeostasis / genetics
  • Mutation / physiology
  • Nerve Net / physiology*
  • Neurons / physiology*
  • Oocytes
  • Organ Culture Techniques
  • Palinuridae / cytology
  • Palinuridae / physiology*
  • Periodicity
  • Potassium Channels / genetics
  • Potassium Channels / metabolism*
  • Potassium Channels, Voltage-Gated*
  • RNA / pharmacology
  • Shaker Superfamily of Potassium Channels
  • Shal Potassium Channels
  • Synaptic Transmission / genetics
  • Xenopus laevis


  • Potassium Channels
  • Potassium Channels, Voltage-Gated
  • Shaker Superfamily of Potassium Channels
  • Shal Potassium Channels
  • RNA