Expression of Presynaptic Calcium Channels in Xenopus Oocytes
The release of neurotransmitter from nerve terminals is triggered by the influx of calcium ions through voltage-activated channels1–3. In excitable tissues there appear to be a number of different types of Ca channels, based on physiological parameters (single channel conductance, ion selectivity, voltage-dependent activation and inactivation properties) and sensitivity to pharmacological agents (especially dihydropyridines, w-conotoxin (wCgTx) and Cd ions). The type of Ca channel underlying synaptic transmission has not been established, although recent studies of mammalian neurons suggest that N-type channels are involved4, 22.
KeywordsDepression Cadmium Bromide Fractionation Barium
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