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 des cribed by which pyramidal and bipolar neurons with many long (up to 20 0 mu m) dendrites can be obtained, Dissociation of CA1 neurons was ach ieved 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. Whol e-cell currents were elicited by U-tube application of the agonists N- methyl-D-aspartate (NMDA), gamma-aminobutyric acid (GABA), and acetylc holine (ACh), and spontaneous miniature currents were also observed in these neurons. ACh-elicited currents were blocked by methyllycaconiti ne (MLA, 1 nM) and Pb2+ (0.1-10 mu M). These results establish acutely dissociated neurons as a simple and reliable preparation for the stud y of the pharmacology, kinetics and subcellular distribution of ligand -gated ion channels.