High affinity choline transport, a process which occurs uniquely in cholinergic nerve terminals, was found to be surprisingly resistant to postmortem changes, provided that the tissue was stored at refrigeration temperatures immediately after death. Uptake appeared to be normal at three days but was somewhat depleted at five days. If tissues were not refrigerated, postmortem changes occurred much more rapidly. Also, activity related changes in choline uptake were reversed at room temperatures in very short times, that is 10-30 minutes. Depolarization of cholinergic synaptosomes results in an activation of high affinity choline uptake. We tested whether there was such an activation of uptake for other compounds in depolarized tissues. It was found that a preliminary depolarization increased the transport of glutamic acid, aspartic acid, glycine and choline. Depolarization had no effect on the transport of a number of other compounds. These results suggest that various transport systems in nerve terminals are affected by increased neuronal activity. Since neuroleptic drugs are critical for the treatment of schizophrenia, a precise anatomical localization for their receptor sites in brain is important. We utilized light microscopic autoradiographic techniques to localize neuroleptic receptors in rat brain. Our results are in agreement with the notion that a critical function of these drugs is to block dopamine receptors.
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