Combined immunocytochemistry and autoradiographic retrograde axonal tracing for identification of transmitters of projection neurons.

ABSTRACT

A double labeling method is described which combines immunocytochemistry for identification of the neurotransmitter serotonin with autoradiographic retrograde axonal tracing using wheat germ agglutinin (WGA), N-[acetyl-3H]. The permanence, sensitivity, and distinctness of the two labels provide a valuable means for analyzing transmitter-identified projection neurons in the central nervous system. Combined immunohistochemical/autoradiographic preparations, following injections of WGA, N-[acetyl-3H] in the caudate-putamen of mice, revealed large numbers of serotonergic and fewer non-serotonergic raphe-striatal projection neurons.