Current- and voltage-clamp recordings and computer simulations of Kenyon cells in the honeybee

J Neurophysiol. 2004 Oct;92(4):2589-603. doi: 10.1152/jn.01259.2003. Epub 2004 Jun 9.

Abstract

The mushroom body of the insect brain is an important locus for olfactory information processing and associative learning. The present study investigated the biophysical properties of Kenyon cells, which form the mushroom body. Current- and voltage-clamp analyses were performed on cultured Kenyon cells from honeybees. Current-clamp analyses indicated that Kenyon cells did not spike spontaneously in vitro. However, spikes could be elicited by current injection in approximately 85% of the cells. Of the cells that produced spikes during a 1-s depolarizing current pulse, approximately 60% exhibited repetitive spiking, whereas the remaining approximately 40% fired a single spike. Cells that spiked repetitively showed little frequency adaptation. However, spikes consistently became broader and smaller during repetitive activity. Voltage-clamp analyses characterized a fast transient Na+ current (INa), a delayed rectifier K+ current (IK,V), and a fast transient K+ current (IK,A). Using the neurosimulator SNNAP, a Hodgkin-Huxley-type model was developed and used to investigate the roles of the different currents during spiking. The model led to the prediction of a slow transient outward current (IK,ST) that was subsequently identified by reevaluating the voltage-clamp data. Simulations indicated that the primary currents that underlie spiking are INa and IK,V, whereas IK,A and IK,ST primarily determined the responsiveness of the model to stimuli such as constant or oscillatory injections of current.

Publication types

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

MeSH terms

  • Algorithms
  • Animals
  • Bees / physiology*
  • Computer Simulation
  • Delayed Rectifier Potassium Channels
  • Electrophysiology
  • Ion Channel Gating / physiology
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Models, Neurological
  • Neurons / drug effects
  • Neurons / physiology*
  • Patch-Clamp Techniques
  • Potassium Channels, Voltage-Gated / drug effects
  • Potassium Channels, Voltage-Gated / physiology
  • Pupa / physiology
  • Sodium Channels / drug effects
  • Sodium Channels / physiology

Substances

  • Delayed Rectifier Potassium Channels
  • Potassium Channels, Voltage-Gated
  • Sodium Channels