LOCALIZATION OF 2 CHOLINERGIC MARKERS, CHOLINE-ACETYLTRANSFERASE AND VESICULAR ACETYLCHOLINE TRANSPORTER IN THE CENTRAL-NERVOUS-SYSTEM OF THE RAT - IN-SITU HYBRIDIZATION HISTOCHEMISTRY AND IMMUNOHISTOCHEMISTRY

Choline acetyltransferase (ChAT) and vesicular acetylcholine transport er (VAChT) are proteins that are required for cholinergic neurotransmi ssion. Present knowledge concerning the organization of cholinergic st ructures has been derived primarily from immunohistochemistry for ChAT . In the present study, we investigated the distribution of mRNAs and the corresponding proteins for ChAT and VAChT by in situ hybridization histochemistry and immunohistochemistry. The patterns of distribution of perikarya containing ChAT mRNA, ChAT protein, VAChT mRNA,and VAChT protein were similar in most regions, and co-localization in the same neuron of mRNAs for ChAT and VAChT, that of ChAT mRNA and ChAT protei n. and that of VAChT mRNA and VAChT protein were demonstrated. However , in the cerebral cortex and hypothalamus, ChAT-immunoreactive perikar ya were present, but they did not contain mRNAs for ChAT and VAChT, an d VAChT protein. On the other hand, in the cerebellum Purkinje cell bo dies contained VAChT mRNA and VAChT protein, but they did not contain either ChAT mRNA or ChAT protein. Axon bundles were clearly revealed b y immunohistochemistry for ChAT, but they were not detected by that fo r VAChT. Both ChAT and VAChT antibodies revealed preterminal axons and terminal-like structures. In the forebrain, they were present in the olfactory bulb, nucleus of the lateral olfactory tract, olfactory tube rcle, lateral septal nucleus, amygdala, hippocampus, neocortex, caudat e-putamen, thalamus and median eminence of the hypothalamus. In the br ainstem, they were localized in the superior colliculus, interpeduncul ar nucleus and some cranial nerve motor nuclei, and further in the ven tral horn of the spinal cord. These results indicate strongly that ChA T and VAChT are expressed in most of the cholinergic neurons, and that immunohistochemistry for VAChT is as useful to detect cholinergic ter minal fields as that for ChAT. (C) 1997 Elsevier Science B.V.