AHP's, HAP's and DAP's: how potassium currents regulate the excitability of rat supraoptic neurones

J Comput Neurosci. Nov-Dec 2003;15(3):367-89. doi: 10.1023/a:1027424128972.

Abstract

We have constructed mathematical models of the electrical activity of two hypothalamic supraoptic neuro-secretory cell-types, and we support our models with new calcium imaging and in vitro electrophysiological data. These cells are neurones that project to the pituitary gland and secrete either of two hormones, oxytocin or vasopressin, into the blood from their axonal terminals. Oxytocin-secreting and vasopressin-secreting cells are closely related and physically they differ only subtly, however when physiologically stressed their discharge patterns are dramatically distinct. We first show how each potassium current contributes to the action-potentials and after-potentials observed in these cells, and we show how these after-potentials are correlated to intra-cellular calcium elevations. We then show how these currents regulate the excitability of these cells and consequently shape their discharge pattern.

Publication types

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

MeSH terms

  • Animals
  • Calcium / antagonists & inhibitors
  • Calcium / metabolism
  • Calcium / pharmacology
  • Computer Simulation
  • Dose-Response Relationship, Drug
  • Electric Conductivity
  • Electric Stimulation
  • Electrophysiology / methods
  • Female
  • In Vitro Techniques
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology*
  • Models, Biological
  • Neurons / classification
  • Neurons / drug effects
  • Neurons / physiology*
  • Oxytocin
  • Peptides / pharmacology
  • Potassium Channel Blockers / pharmacology
  • Potassium Channels / physiology*
  • Rats
  • Reaction Time / drug effects
  • Reaction Time / physiology
  • Supraoptic Nucleus / cytology
  • Supraoptic Nucleus / drug effects
  • Supraoptic Nucleus / physiology*
  • Time Factors
  • Vasopressins

Substances

  • Peptides
  • Potassium Channel Blockers
  • Potassium Channels
  • Vasopressins
  • Oxytocin
  • iberiotoxin
  • Calcium