title: Physiological properties of periodontal mechanosensitive neurones in the trigeminal (Gasserian) ganglion of the rat.
abstract: Periodontal mechanosensitive (PM) primary afferent neurones were recorded from the rat trigeminal ganglion and their response to mechanical tooth stimulation studied. The majority (95%) of PM afferents were single-tooth units and most were sensitive to mechanical stimulation of the incisor. They had a sustained response to pressure applied to the tooth, and showed a directional selectivity to the stimulation. Only a small number (5%) of units were multi-tooth sensitive; their receptive fields were restricted to the molars. When the incisor was stimulated mechanically in 12 directions in a plane perpendicular to the axis of the tooth crown, the predominant response fields of the PM units were of the medium type (90-180 degree response angle) or the broad type (180-360 degrees). Each unit had single optimal stimulus direction oriented predominantly in the rostrocaudal or caudorostral direction. About 60% of the PM units responded to tooth stimulation at irregular spike intervals, whereas the remaining 40% fired at relatively regular intervals. When the tooth was stimulated at a force of 0.05 N, the mean spike interval and rate of spike-interval fluctuation [percentage of the standard deviation (SD) of the interval distribution to the mean interval (mean); SD/mean x 100] were 29.2 ms and 38.1% for the regular-interval units, and 15.1 ms and 8.8% for the irregular-interval ones. The mean spike interval of the regular units was significantly longer than that of the irregular ones.
authors.affiliation: Department of Physiology, Tohoku University School of Dentistry, Sendai, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tabata
authors.forename: H
authors.initials: H
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D002415:Cats; D004285:Dogs; D004594:Electrophysiology; D008465:Mechanoreceptors / Q000502:physiology*; D008839:Microelectrodes; D009475:Neurons, Afferent / Q000502:physiology*; D010513:Periodontal Ligament / Q000294:innervation*; D010812:Physical Stimulation; D011312:Pressure; D051381:Rats; D012668:Trigeminal Ganglion / Q000502:physiology*