Temporomandibular-evoked jaw muscle reflex: role of brain stem NMDA and non-NMDA receptors.
This study investigated the possible involvement of brain stem excitatory amino acid receptor mechanisms and the trigeminal subnucleus caudalis (Vc) in temporomandibular joint (TMJ)-evoked reflex jaw muscle activity. Glutamate injected into the TMJ of anesthetized rats reflexly evoked activity in the jaw muscles. Application of lidocaine, but not saline, to the surface of the caudal brainstem overlying Vc significantly suppressed TMJ-evoked jaw muscle activity, while application of NMDA or non-NMDA receptor antagonists also significantly attenuated jaw muscle activity. These results provide evidence that Vc is a critical relay in the TMJ-evoked reflex activation of the jaw muscles, and that both NMDA and non-NMDA receptor mechanisms may contribute to these effects.
Cairns
B E
BE
Faculty of Dentistry, The University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada.
Sessle
B J
BJ
Hu
J W
JW
D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D004396:Coloring Agents / Q000493:pharmacokinetics; D004576:Electromyography; D005070:Evans Blue / Q000493:pharmacokinetics; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008410:Masticatory Muscles / Q000187:drug effects / Q000294:innervation* / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects* / Q000378:metabolism; D012018:Reflex / Q000187:drug effects* / Q000502:physiology; D013704:Temporomandibular Joint / Q000187:drug effects* / Q000294:innervation* / Q000502:physiology; D014275:Trigeminal Caudal Nucleus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D000779:Anesthetics, Local; D004396:Coloring Agents; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D005070:Evans Blue; D008012:Lidocaine