title: Facilitation of masseter EMG and masseteric (jaw-closure) reflex by serotonin in behaving cats.
abstract: The trigeminal motor nucleus (MoV) contains the somata of the motoneurons that control jaw position and jaw movements. This nucleus is of neurochemical interest because it receives a dense serotonergic input. We examined the effects of application of serotonin or fluoxetine, a serotonin reuptake blocker, into this nucleus on the spontaneous or reflex (jaw-closure) electrical activity of the masseter muscle in behaving cats. Serotonin produced a clearcut enhancement of both spontaneous and reflex activities. This action was attenuated by previous systemic injection of the serotonin receptor antagonist methysergide. The effect was mimicked to a certain extent by fluoxetine. These data provide evidence that the serotonergic input to MoV exerts a general facilitatory influence on masseter motoneurons activity.
authors.affiliation: Department of Psychology, Princeton University, NJ 08544.
authors.forename: L E
authors.initials: LE
authors.lastname: Ribeiro-do-Valle
authors.forename: C W
authors.initials: CW
authors.lastname: Metzler
authors.forename: B L
authors.initials: BL
authors.lastname: Jacobs
mesh_terms: D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D008297:Male; D008406:Masseter Muscle / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D012016:Reference Values; D012018:Reflex / Q000187:drug effects*; D012701:Serotonin / Q000494:pharmacology*; D014278:Trigeminal Nuclei / Q000187:drug effects / Q000502:physiology*
chemical_list: D012701:Serotonin