title: A dual effect of sympathetic nerve stimulation on jaw muscle spindles.
abstract: In anaesthetized and paralyzed rabbits, electrical stimulation of the cervical sympathetic nerve at physiological frequencies induces in jaw muscle spindle afferents a short-latency decrease or suppression of discharge. This effect is very stereotyped in pattern and is attributed to direct sympathetic innervation of spindles. It is mediated by preganglionic S1-S2 sympathetic fiber groups. A longer-latency facilitatory effect follows, probably vasomotor in origin and mediated by S3-S4 groups. Both responses are eliminated by administration of alpha-adrenergic blocking agents. The latencies, patterns, thresholds, durations and reproducibility of these responses have been studied and the mechanisms possibly involved are discussed.
mesh_terms: D000818:Animals; D002344:Carotid Body / Q000502:physiology; D002346:Carotid Sinus / Q000502:physiology; D008410:Masticatory Muscles / Q000098:blood supply / Q000294:innervation*; D008636:Mesencephalon / Q000502:physiology; D009470:Muscle Spindles / Q000187:drug effects*; D011817:Rabbits; D011930:Reaction Time / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology*; D014278:Trigeminal Nuclei / Q000502:physiology; D014661:Vasoconstriction