Takata M, Tomioka S, Tomomune N
Department of Physiology, School of Dentistry, Tokushima University, Japan.
Exp Brain Res. 1992;90(2):233-40. doi: 10.1007/BF00227234.
Excitation and inhibition of temporal and digastric motoneurons (Temp. and Dig. Mns) during transient jaw closing, the so-called jaw-closing reflex, were studied in cats. Application of diffuse pressure stimulation to the posterior palatal surface produced the jaw-closing reflex and it was found that mechanosensory inputs from the posterior palatal mucosa produce depolarizing potentials on the Temp. Mns responsible for jaw closure during the jaw-closing reflex. We have demonstrated that in one-third of 27 explored Temp. Mns the initial bursts of spikes were elicited before the onset of jaw closure, suggesting that these cells contribute to initiate jaw closure during the jaw-closing reflex. The remaining cells probably contributed to maintain the occlusal phase. Furthermore, it was found that mechanosensory inputs from the posterior palatal mucosa produce a hyperpolarization-depolarization sequence in the Dig. Mns responsible for the jaw-closing reflex. In addition, when pressure stimulation was applied to the anterior palatal mucosa, sustained jaw opening was elicited and an increase of firing frequency of Dig. Mns occurred 40 ms before the onset of jaw opening and continued for 80 ms.
在猫身上研究了瞬态闭口（即所谓的闭口反射）过程中颞肌和二腹肌运动神经元（Temp.和Dig. Mns）的兴奋和抑制情况。向后腭表面施加弥散性压力刺激可产生闭口反射，并且发现来自后腭黏膜的机械感觉输入在闭口反射期间会在负责闭口的Temp. Mns上产生去极化电位。我们已经证明，在27个被探究的Temp. Mns中，有三分之一在闭口开始之前就引发了最初的一串动作电位，这表明这些细胞在闭口反射期间有助于启动闭口动作。其余的细胞可能有助于维持咬合阶段。此外，还发现来自后腭黏膜的机械感觉输入在负责闭口反射的Dig. Mns中产生超极化 - 去极化序列。另外，当向前腭黏膜施加压力刺激时，会引发持续的张口动作，并且在张口开始前40毫秒Dig. Mns的放电频率增加，并持续80毫秒。
