The cat substantia nigra (SN) pars reticulata (SNR) has been observed electron microscopically after ibotenic acid injections into the caudate nucleus (Cd) and horseradish peroxidase injections into the nucleus tegmenti pedunculopontinus pars compacta (TPC). As a result, degenerating striatal terminals were found to make symmetric synaptic contacts on retrogradely labeled SNR neurons. The present findings, together with our previous study on the tegmentonigrostriatal projection (Tokuno et al., Neurosci. Lett. 85 (1988) 1-4), confirm that the Cd has indirect reciprocal connections with the TPC via the SN.
Animals Cats