Physiological characteristics of periodontal mechanosensitive neurones in the inferior alveolar nerve of the cat.
Unitary discharges of periodontal mechanosensitive (PM) fibres were recorded from cat inferior alveolar nerve. More than half (66%) of the PM units were single-tooth ones sensitive to only one tooth. The majority (78%) responded sustainedly to stimulation of the mandibular canine tooth. The multitooth units responded predominantly to stimulation of the canine and incisor teeth. A broad-type response field, with a directional range of 180-360 degrees for the response angle, was most frequent. The optimal stimulus direction was oriented in the caudomedial or caudolateral direction. Most (93%) of the single-tooth and multitooth PM units were fired at relatively regular spike intervals by tooth stimulation. In the multitooth units, conditioning and test stimuli were applied to a pair of teeth in the receptive field in order to examine the mechanical spread effect of the conditioning stimulus on the adjacent tooth. The conditioning stimulus was given in the optimal stimulus direction and the test stimulus in the direction opposite to that direction. All multitooth units of the regular spike-interval type had only one tooth ('firing-stopped' tooth) in their receptive fields, the test stimulus to which stopped the discharges evoked by the conditioning stimuli to other teeth. The firing-stopped tooth, however, was rare in multitooth units of the irregular spike interval type.
Tabata
T
T
Department of Physiology, Tohoku University School of Dentistry, Sendai, Japan.
Suzuki
T
T
Watanabe
M
M
D000818:Animals; D002415:Cats; D008340:Mandibular Nerve / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D010519:Periodontium / Q000294:innervation* / Q000502:physiology; D012684:Sensory Thresholds