Ligand-gated ion channels in acutely dissociated rat hippocampal neurons with long dendrites.

A technique for dissociation of hippocampi of 3-25-day-old rats is described by which pyramidal and bipolar neurons with many long (up to 200 microns) dendrites can be obtained. Dissociation of CA1 neurons was achieved by mechanical means, in the absence of Ca2+, and without the use of proteolytic enzymes. The functional properties of the dissociated neurons were assessed using the whole-cell patch-clamp technique. Whole-cell currents were elicited by U-tube application of the agonists N-methyl-D-aspartate (NMDA), gamma-aminobutyric acid (GABA), and acetylcholine (ACh), and spontaneous miniature currents were also observed in these neurons. ACh-elicited currents were blocked by methyllycaconitine (MLA, 1 nM) and Pb2+ (0.1-10 microM). These results establish acutely dissociated neurons as a simple and reliable preparation for the study of the pharmacology, kinetics and subcellular distribution of ligand-gated ion channels.