title: AHP's, HAP's and DAP's: how potassium currents regulate the excitability of rat supraoptic neurones.
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.
authors: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA. pete.roper@nih.gov
authors: Peter
authors: P
authors: Roper
authors: Joseph
authors: J
authors: Callaway
authors: Talent
authors: T
authors: Shevchenko
authors: Ryoichi
authors: R
authors: Teruyama
authors: William
authors: W
authors: Armstrong
mesh_terms: D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D003198:Computer Simulation; D004305:Dose-Response Relationship, Drug; D004553:Electric Conductivity; D004558:Electric Stimulation; D004594:Electrophysiology / Q000379:methods; D005260:Female; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological; D009474:Neurons / Q000145:classification / Q000187:drug effects / Q000502:physiology*; D010121:Oxytocin; D010455:Peptides / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013495:Supraoptic Nucleus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014667:Vasopressins
chemical_list: D010455:Peptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D014667:Vasopressins; D010121:Oxytocin; C064719:iberiotoxin; D002118:Calcium