title: Control of low-threshold exocytosis by T-type calcium channels.
abstract: Low-voltage-activated (LVA) T-type Ca²⁺ channels differ from their high-voltage-activated (HVA) homologues by unique biophysical properties. Hence, whereas HVA channels convert action potentials into intracellular Ca²⁺ elevations, T-type channels control Ca²⁺ entry during small depolarizations around the resting membrane potential. They play an important role in electrical activities by generating low-threshold burst discharges that occur during various physiological and pathological forms of neuronal rhythmogenesis. In addition, they mediate a previously unrecognized function in the control of synaptic transmission where they directly trigger the release of neurotransmitters at rest. In this review, we summarize our present knowledge of the role of T-type Ca²⁺ channels in vesicular exocytosis, and emphasize the critical importance of localizing the exocytosis machinery close to the Ca²⁺ source for reliable synaptic transmission. This article is part of a Special Issue entitled: Calcium channels.
authors.affiliation: Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, 3330 Hospital Dr. NW, Calgary, Canada T2N4N1. norbert.weiss@yahoo.fr
authors.forename: Norbert
authors.initials: N
authors.lastname: Weiss
authors.forename: Gerald W
authors.initials: GW
authors.lastname: Zamponi
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020747:Calcium Channels, T-Type / Q000502:physiology*; D005089:Exocytosis / Q000502:physiology*; D006801:Humans; D018377:Neurotransmitter Agents / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D020747:Calcium Channels, T-Type; D018377:Neurotransmitter Agents; D002118:Calcium