Matsumoto Norio, Sato Tadasi, Yahata Fumikazu, Suzuki Takashi A
Department of Oral Physiology, School of Dentistry, Iwate Medical University, Morioka, Iwate 020 Japan.
Pain. 1987 Nov;31(2):249-262. doi: 10.1016/0304-3959(87)90040-6.
Tooth pulp-driven (TPD) neurons are found in the oral area of the first somatosensory cortex (SI) of the cat. They have been classified according to their discharge patterns in response to electrical stimulation of the tooth pulp: the fast (F) type, slow (S) type, and a fast (Fa) type accompanied by afterdischarges. The characteristics of each type of TPD neuron were investigated in cats anesthetized with nitrous oxide and halothane. In surface distribution, there was no biased localization for any of the types. However, F-type neurons receiving input from the mandibular tooth tended to be found more medially than F-types receiving maxillary input. These TPD neurons did not change their firing pattern even when the stimulus was intensified. Mean threshold of the F-type to tooth pulp stimulation was 7.8 +/- 1.6 V and tended to be lower than that of the S-type (16.3 +/- 3.0 V). Graded increases in tooth pulp stimulation produced progressive increases in discharge frequency of both types of neurons. An analysis of the power function in relation to stimulus vs. response demonstrated that the exponent of the S-type neuron was about 2.0, being significantly larger compared to the 0.8 value for the F-type. The mean number of pulps afferent to an F-type was 1.6, compared to 4.8 for an S-type or 4.3 for an Fa-type. The results suggest that F-type TPD neurons may play a more important part in localizing pulpal pain and in recognizing the intensity than the other types.
牙髓驱动（TPD）神经元见于猫第一躯体感觉皮层（SI）的口腔区域。它们已根据对牙髓电刺激的放电模式进行了分类：快速（F）型、慢速（S）型以及伴有后放电的快速（Fa）型。在使用一氧化二氮和氟烷麻醉的猫身上研究了每种类型TPD神经元的特征。在表面分布上，任何一种类型都没有偏向性定位。然而，接受下颌牙齿输入的F型神经元往往比接受上颌输入的F型神经元更靠内侧。即使刺激增强，这些TPD神经元也不会改变其放电模式。F型对牙髓刺激的平均阈值为7.8 +/- 1.6伏，且往往低于S型（16.3 +/- 3.0伏）。牙髓刺激的分级增加会使两种类型神经元的放电频率逐渐增加。对刺激与反应关系的幂函数分析表明，S型神经元的指数约为2.0，与F型的0.8值相比明显更大。F型的平均牙髓传入数量为1.6个，而S型为4.8个，Fa型为4.3个。结果表明，F型TPD神经元在定位牙髓疼痛和识别强度方面可能比其他类型发挥更重要的作用。
