Properties and Distribution of Single Voltage-Gated Calcium Channels in AdultHippocampal Neurons

摘要

The properties of single voltage-gated calcium channels were investigated inacutely-exposed CA3 and CA1 pyramidal neurons and granule cells of area dentata in the adult guinea pig hippocampal formation. Guinea pig hippocampal slices were prepared in a conventional manner, then treated with proteolytic enzymes and gently shaken to expose the somata of the three cell types studied. Standard patch-clamp techniques were used to record current flow through calcium channels in cell-attached membrane patches with isotonic barium as the charge carrier. Single channel current amplitudes were measured at different membrane potentials. Single channel current-voltage plots were constructed and single channel slope conductances were found to fall into three classes, These were (approximately): 8, 14, and 25 pS, and were observed in all three cell types.