Multipolar neurons and axodendritic synapses in the mesencephalic trigeminal nucleus of the cat.

In the mesencephalic trigeminal nucleus (MTN) of the adult cat, multipolar neurons with 1-9 smooth dendritic processes were labeled with horseradish peroxidase which was applied to central cut ends of the masseter, deep temporal, medial pterygoid, superior alveolar and inferior alveolar nerves. These constituted 40% of the total population of MTN neurons; most of them were jaw-closing muscle afferent neurons and located mainly at the levels of the superior colliculus. Axon terminals were found electron microscopically to make synaptic contacts upon horseradish peroxidase-labeled dendritic profiles of MTN neurons.