An in vitro jaw-nerve preparation for oral sensory study in the rat

We have developed an in vitro jaw-nerve preparation in Wistar albino rats, suitable for the quantitative study of peripheral sensory mechanisms in the oral region. The mandible on one side was excised together with the inferior alveolar nerve and was kept in a modified Krebs-Henseleit solution saturated with O2/CO2 (95:5) gas mixture. Recordings were made from single afferent fibers in the inferior alveolar nerve in response to mechanical stimulation of various oral sites (oral mucosa, periodontal ligament and tooth pulp) by calibrated von Frey hairs. In the case of tooth pulp stimulation, heat and chemical (bradykinin) stimuli were also used. Stable unitary recordings could be made for up to 5 h which was long enough to record the activities evoked by various stimuli applied to the oral area. This paper will describe the procedure for making this preparation together with some responses of single units in the inferior alveolar nerve to mechanical, thermal and chemical stimulations applied to this preparation.