Matsumoto N, Sato T, Ooe M, Suzuki T A
Department of Oral Physiology, School of Dentistry, Iwate Medical University, Japan.
Arch Oral Biol. 1988;33(4):251-6. doi: 10.1016/0003-9969(88)90186-0.
About 40 per cent of tooth pulp-driven (TPD) neurones received afferent fibres from the ipsilateral tooth pulp. This ipsilateral afferent pathway was investigated in cats anaesthetized with nitrous oxide and halothane. The subcortical temperature of the brain was lowered to about 28 degrees C by perfusion of cold water within a thermode. Cooling the homotopic area contralateral to the recording site caused little change in the firing rate of short-latency TPD neurones upon ipsilateral pulp stimulation (n = 13). Microinjection (1-2 microliters) of 1 per cent lidocaine into the ipsilateral nucleus ventralis posteromedialis (VPM) caused significant diminution in the firing rate of short-latency TPD neurones (n = 11) to ipsilateral stimulation but not of long-latency TPD neurones (n = 8). About 35 per cent (13/35) of the TPD neurones distributed in the medial shell region of the VPM proper responded with short latency to ipsilateral pulp stimulation. These findings suggest that the ipsilateral input to short-latency TPD neurones in the oral area is carried via projection fibres from the ipsilateral VPM but not via commissural ones, and that the ipsilateral input to long-latency neurones is probably relayed in a site other than the ipsilateral VPM.
约40%的牙髓驱动（TPD）神经元从同侧牙髓接收传入纤维。在用氧化亚氮和氟烷麻醉的猫中研究了这条同侧传入通路。通过在热电极内灌注冷水，将大脑皮质下温度降至约28摄氏度。冷却记录部位对侧的同位区域，在同侧牙髓刺激时，短潜伏期TPD神经元的放电率几乎没有变化（n = 13）。向同侧内侧后腹核（VPM）微量注射（1 - 2微升）1%利多卡因，可使短潜伏期TPD神经元（n = 11）对同侧刺激的放电率显著降低，但对长潜伏期TPD神经元（n = 8）无影响。分布在VPM内侧壳区的约35%（13/35）的TPD神经元对同侧牙髓刺激有短潜伏期反应。这些发现表明，口腔区域短潜伏期TPD神经元的同侧输入是通过来自同侧VPM的投射纤维而非连合纤维传导的，并且长潜伏期神经元的同侧输入可能在同侧VPM以外的部位中继。
