On whether there is a direct sympathetic influence on jaw muscle spindles.
Electric stimulation of the peripheral stump of cervical sympathetic nerve (0.5-5.0 sec trains at 1 msec, 6-10 V, 0.5-30 HZ) induced in jaw muscle spindle afferents: (1) decrease of discharge frequency with 0.6-2.5 sec latency, lasting 8-13 sec (in 40% of the units) possibly due to direct sympathetic innervation of spindles; and (2) subsequent modest increase of frequency, probably secondary to muscular vasoconstriction.
D000320:Adrenergic Fibers / Q000502:physiology*; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials; D005728:Ganglia, Sympathetic / Q000502:physiology*; D007568:Jaw / Q000294:innervation*; D008410:Masticatory Muscles / Q000294:innervation; D008636:Mesencephalon / Q000502:physiology; D009470:Muscle Spindles / Q000502:physiology*; D011817:Rabbits; D014278:Trigeminal Nuclei / Q000502:physiology