Pontomedullary glutamate receptors mediating locomotion and muscle tone suppression.

TitlePontomedullary glutamate receptors mediating locomotion and muscle tone suppression.
Publication TypeJournal Article
Year of Publication1991
AuthorsLai YY, Siegel JM
JournalJ Neurosci
Date Published1991 Sep
Keywords6-Cyano-7-nitroquinoxaline-2,3-dione, Animals, Cats, Electric Stimulation, Female, Kainic Acid, Kinetics, Locus Coeruleus, Male, Medulla Oblongata, Motor Activity, Muscles, N-Methylaspartate, Pons, Quinoxalines, Quisqualic Acid, Receptors, Glutamate, Receptors, Neurotransmitter

Microinjection of NMDA and non-NMDA agonists into the same sites in pontomedullary motor "inhibitory" areas of decerebrate animals produced opposite effects on muscle tone. Microinjection of non-NMDA agonists into peri-locus coeruleus alpha (peri-LC alpha) and nucleus magnocellularis (NMC) suppressed muscle tone, while injection of NMDA agonists at the same sites increased muscle tone and produced locomotion. The latency, duration, and magnitude of muscle tone change after both NMDA and non-NMDA agonist injections were dose dependent. Increased muscle tone and locomotor effects were blocked by NMDA antagonists, and muscle tone suppression effects were blocked by non-NMDA antagonists. We conclude that pontomedullary non-NMDA receptors mediate muscle tone suppression, and that NMDA receptors mediate locomotion and muscle tone facilitation. Activation of both NMDA and non-NMDA pontomedullary receptors by glutamate release in REM sleep can explain the combination of motor activation and loss of muscle tone that characterizes this state. In the waking animal, the co-localization of these mechanisms may facilitate the coordination of locomotion with postural adjustments.

Alternate JournalJ Neurosci
PubMed ID1679125
PubMed Central IDPMC6575245
Grant ListHL41370 / HL / NHLBI NIH HHS / United States
MH43811 / MH / NIMH NIH HHS / United States
NS14610 / NS / NINDS NIH HHS / United States