Fine structure of target neurons of antischizophrenic drugs in the neostriatum--ultracytochemical observation of dopamine and acetylcholine interaction.

In order to show the fine structure of target neurons of antischizophrenic drugs in the neostriatum, acetylcholinergic neurons were identified by means of choline acetyltransferase (ChAc) and acetylcholinesterase (AChE) cytochemistry. Two types of neurons were revealed to have ChAc activity and at the same time to be synthesizing sites of AChE. It was observed that both types of neuron receive boutons containing ChAc positive synaptic vesicles at the soma and/or the dendrite. Moreover, both types of neuron were revealed to be postsynaptic sites of dopaminergic synapses from the fact that degenerated boutons after coagulation of the substantia nigra and boutons containing granular synaptic vesicles after incubation with alpha-methylnoradrenaline, contact the soma of the cholinergic neurons. It is speculated that both cholinergic neurons may be reciprocally influenced as in the case of motor neurons and Renshaw cells in the spinal anterior horn.