title: Classification of presynaptic calcium channels at the squid giant synapse: neither T-, L- nor N-type.
abstract: We examined both pharmacological and functional characteristics of the calcium channels which trigger transmitter secretion from giant nerve terminals of squid. These calcium channels are insensitive to organic calcium channel blockers such as dihydropyridines and omega-conotoxin GVIA, moderately sensitive to cadmium, activated by very small depolarizations and slowly inactivating. We conclude that the characteristics of these presynaptic channels do not correspond to the properties of T-, L-, or N-type calcium channels found in other cells.
authors.affiliation: Physiology Department, MSB, University of Toronto, Ont., Canada.
authors.forename: M P
authors.initials: MP
authors.lastname: Charlton
authors.forename: G J
authors.initials: GJ
authors.lastname: Augustine
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002965:Classification; D049832:Decapodiformes; D004095:Dihydropyridines / Q000494:pharmacology; D015640:Ion Channel Gating / Q000187:drug effects; D008978:Mollusk Venoms / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D020866:omega-Conotoxin GVIA
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D004095:Dihydropyridines; D008978:Mollusk Venoms; D020866:omega-Conotoxin GVIA