K+ channel activation and low-threshold Ca2+ spike of rat cerebellar Purkinje cells in vitro.
Using the whole-cell configuration of the patch-clamp recording method, we analyzed the role of K+ conductances in determining the characteristics of the dendritically-initiated low-threshold Ca+ spike (LTS) recorded at the somatic level of rat cerebellar Purkinje cells (PCs) in slice cultures. Blockade of tetra-ethyl-ammonium-(TEA)- and 4-aminopyridine-(4-AP)-sensitive K+ channels increased the amplitude of the LTS. This effect was prominent with 4-AP, which promotes the fast-decaying component of the LTS. Surprisingly, a shortening of the LTS was induced by the blockade of K+ channel activity instead of a broadening of spikes as generally observed. We propose that, when propagating to the soma, TEA- and 4-AP-sensitive K+ channel activity affects the electrical properties of dendrites such that the LTS is attenuated and slowed down.
Cavelier
Pauline
P
Laboratoire de Neurobiologie Cellulaire, CNRS, Centre de Neurochimie, F-67084 Strasbourg Cedex, France.
Desplantez
Thomas
T
Beekenkamp
Huguette
H
Bossu
Jean-Louis
JL
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D002531:Cerebellum / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology*; D011689:Purkinje Cells / Q000187:drug effects / Q000502:physiology*; D051381:Rats
D015220:Calcium Channels; D026902:Potassium Channel Blockers; D015221:Potassium Channels