Synaptic Connections of Mylohyoid Primary Afferent Terminals Made on Jaw-Opening Muscle Motoneurons in the Rat

application/pdfHorseradish peroxidase conjugated with wheat germ agglutinin (HRP-WGA) was injected into the muscle branch of the mylohyoid nerve in rats. HRP-labeled neuronal cell bodies were observed ipsilaterally in the caudal portion of the trigeminal mesencephalic nucleus and the ventromedial division of the trigeminal motor nucleus (Vmo.vm). Electron microscope observations were carried out on sections through Vmo.vm containing HRP-labeled cell bodies. Synaptic contacts were found between HRP-labeled axon terminals and HRP-labeled nerve cells. The results suggested that mylohyoid muscle spindle afferents are synaptic contacts on the mylohyoid motoneurons.journal articl