Whole-cell voltage-clamp recordings in granule cells acutely isolated from hippocampal slices of adult or aged rats.

Whole-cell voltage-clamp recordings were undertaken in granule cells acutely dissociated by a simple enzymatic procedure from the dentate gyri of hippocampal slices obtained from adult or aged rats. This dissociation procedure also allowed the concomitant isolation of other neuron types from diverse hippocampal subfields for the study of ionic currents through voltage- and neurotransmitter-gated channels. For example, in isolated granule cells of the dentate gyrus both transient and sustained Ca2+ currents could be observed in the presence of extracellular tetrodotoxin (TTX) and intracellular Cs+. In addition, ionic currents mediated by activation of excitatory amino acid receptors of the N-methyl-D-aspartate (NMDA) type were present. A technique for the rapid dissociation of neurons from brain slices of adult or aged rats is described in detail.