The Journal of Neurophysiology Vol. 78 No. 3 September 1997, pp. 1720-1725
Copyright ©1997 The American Physiological Society

RAPID COMMUNICATION

In Vitro Investigation of Synaptic Relations Between Interneurons Surrounding the Trigeminal Motor Nucleus and Masseteric Motoneurons

Arlette Kolta

Faculté de Médecine Dentaire, Université de Montréal, Succursale Centre-Ville, Montreal, Quebec H3C 3J7; and Faculty of Dentistry, McGill University, Montreal, Quebec H3A 2B2, Canada

Kolta, Arlette. In vitro investigation of synaptic relations between interneurons surrounding the trigeminal motor nucleus and masseteric motoneurons. J. Neurophysiol. 78: 1720-1725, 1997. Because of their many inputs and bilateral projections, interneurons surrounding the trigeminal motor nucleus (MotV) are thought to be very important in control of jaw movements and reflexes. However, their interactions with the trigeminal motoneurons are almost unknown. In the present study an in vitro slice preparation was used to investigate this relationship in rat. The zone bordering MotV has been subdivided into four regions: the supra-, juxta-, and intertrigeminal areas (SupV, JuxtV, and IntV, respectively) and the parvocellular reticular formation ventral and caudal to MotV. Stimulation of all areas evoked short-latency excitatory postsynaptic potentials (EPSPs) in masseteric motoneurons. Frequently the EPSPs masked inhibitory postsynaptic potentials (IPSPs) or were followed by long-lasting inhibitory potentials. Only responses obtained from stimulation of JuxtV and IntV seemed devoid of inhibitory components. The EPSPs were mediated through kainate/-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, whereas the IPSPs appear to be due to -aminobutyric acid and glycine. EPSPs and IPSPs were also recorded in SupV premotor interneurons after stimulation of IntV and MotV, respectively, thus suggesting that reciprocal connections exist between premotor areas and also between premotor interneurons of SupV and inhibitory interneurons located within MotV. It is concluded that the preparation used here will doubtless prove useful for further investigation of the circuitry involved in the bilateral coordination of the jaw.

This article has been cited by other articles:

				S. Nakamura, T. Inoue, K. Nakajima, M. Moritani, K. Nakayama, K. Tokita, A. Yoshida, and K. Maki Synaptic Transmission From the Supratrigeminal Region to Jaw-Closing and Jaw-Opening Motoneurons in Developing Rats J Neurophysiol, October 1, 2008; 100(4): 1885 - 1896. [Abstract] [Full Text] [PDF]

				C. Burgess, D. Lai, J. Siegel, and J. Peever An Endogenous Glutamatergic Drive onto Somatic Motoneurons Contributes to the Stereotypical Pattern of Muscle Tone across the Sleep-Wake Cycle J. Neurosci., April 30, 2008; 28(18): 4649 - 4660. [Abstract] [Full Text] [PDF]

				H. Koizumi, K. Nomura, K. Ishihama, T. Yamanishi, A. Enomoto, and M. Kogo Inhibition of Trigeminal Respiratory Activity by Suckling Journal of Dental Research, November 1, 2007; 86(11): 1073 - 1077. [Abstract] [Full Text] [PDF]

				F. Deriu, E. Tolu, and J. C Rothwell A short latency vestibulomasseteric reflex evoked by electrical stimulation over the mastoid in healthy humans J. Physiol., November 15, 2003; 553(1): 267 - 279. [Abstract] [Full Text] [PDF]

				Z. Chen and J. B. Travers Inactivation of amino acid receptors in medullary reticular formation modulates and suppresses ingestion and rejection responses in the awake rat Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2003; 285(1): R68 - R83. [Abstract] [Full Text] [PDF]

				M.-J. Bourque and A. Kolta Properties and Interconnections of Trigeminal Interneurons of the Lateral Pontine Reticular Formation in the Rat J Neurophysiol, November 1, 2001; 86(5): 2583 - 2596. [Abstract] [Full Text] [PDF]

				A. Yoshida, H. Fukami, Y. Nagase, K. Appenteng, S. Honma, L.-F. Zhang, Y. C. Bae, and Y. Shigenaga Quantitative Analysis of Synaptic Contacts Made between Functionally Identified Oralis Neurons and Trigeminal Motoneurons in Cats J. Neurosci., August 15, 2001; 21(16): 6298 - 6307. [Abstract] [Full Text] [PDF]

				J. C. Rekling, G. D. Funk, D. A. Bayliss, X.-W. Dong, and J. L. Feldman Synaptic Control of Motoneuronal Excitability Physiol Rev, April 1, 2000; 80(2): 767 - 852. [Abstract] [Full Text] [PDF]