THE EXCITATORY ACTION OF ACETYLCHOLINE ON HIPPOCAMPAL NEURONES OF THE GUINEA PIG AND RAT MAINTAINED IN VITRO

摘要: Abstract In preliminary experiments on 39 identified pyramidal cells in the vitro slice preparation of guinea-pig hippocampus depolarization evoked by acetylcholine (ACh) applied microiontophoresis was always associated with an increase membrane resistance. 9 slices cut from rat similar results were obtained 24 cells. a more detailed analysis 13 hippocampus, whose mean resting potential — 74 mV and input resistance 33 Mω, peak ACh 11.6 12 Mω. The reversal for excitatory action 29 hyperpolarizing than potential. linearly related to corresponding before after application ACh. This true throughout each individual applications response applications. constancy this relationship is compatible usual model used describe synaptic events thought be mediated closure ionic channels which are open absence transmitter. onset approximately 4 times slower that near equipotent microiontophoretic glutamate adjacent barrel same multibarrelled micropipette. Following ACh, recovery also slow and, average, 10 longer following glutamate. It suggested offset responses not models based diffusion best explained postulating sequential generation one or intermediates.