Physiological and morphological analyses of mechanoreceptors in the geniohyoid muscle of the cat were carried out. The receptor responded to light pressure applied to the muscle, and afferent nerve fibers from the receptors showed rapidly adapting discharges. The threshold of the receptor to pressure was lower than 1 gr. The receptor followed each cycle of vibratory stimulation in 1 : 1 ratio below a frequency range of 60-80 c/s, but did not respond to higher frequency stimulation of 200-300 c/s. Stretch of the muscle caused firing of the afferent fibers from the receptors, and their discharges were rapidly adaptive. The threshold for stretch was within the range of 40-200 gr. Phasic contraction of the muscle caused usually 1, rarely 2 spikes. Succinylcholine (500 μg/kg) injection did not show excitatory effects on the receptors. The receptors were remarkably stimulated by injection of 6% NaCl into the geniohyoid muscle. These mechanoreceptors are mainly detected in the anterior half of the muscle. Cajal's silver staining method was employed for morphological evaluation of the receptors. A small number of encapsulated endings were recognized in the connective tissue between muscle fibers.
|Number of pages||7|
|Journal||Journal of Osaka University Dental Society|
|Publication status||Published - 1972|
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