Inhibitory commissural connections of neurones in the trigeminal motor nucleus of the rat.
Physiological evidence is presented for the existence of commissural fibres that cross the midsagittal plane in the medulla of the rat at the level of the trigeminal motor nucleus (Mo5). These fibres, which have their origin in the Mo5, terminated in the contralateral Mo5. Small inhibitory postsynaptic potentials were recorded in jaw-closing motoneurones by electrical activation of the commissural fibres; jaw-opening and fusimotor neurones as well as the jaw-closing and jaw-opening reflex were not affected. Electromyographic recordings from jaw-closing and jaw-opening muscles in the unrestrained rat showed that masseter activity was inhibited by the commissural fibres. These trigeminal commissural connections might play a part in the co-ordination of bilateral activity of the jaw-closing musculature during unilateral chewing.
Jüch
P J
PJ
Department of Neurobiology and Oral Physiology, University of Groningen, The Netherlands.
Minkels
R F
RF
van Willigen
J D
JD
D000818:Animals; D004558:Electric Stimulation; D004576:Electromyography; D007395:Interneurons / Q000502:physiology*; D008297:Male; D008406:Masseter Muscle / Q000294:innervation* / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D009334:Neck Muscles / Q000294:innervation / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology; D051381:Rats / Q000033:anatomy & histology*; D017208:Rats, Wistar; D014278:Trigeminal Nuclei / Q000166:cytology* / Q000502:physiology