Takata M, Ito K, Kawamura Y
Jpn J Physiol. 1975;25(4):453-65. doi: 10.2170/jjphysiol.25.453.
The synaptic linkage of jaw-opening muscle afferents with the retractive and the protrusive motoneurons (R-Mns and P-Mns) in the hypoglossal motor nucleus was explored in anesthetized cats. It was found that stimulation of low-threshold afferents arising in the jaw-opening muscles (m. mylohyoideus and m. digastricus) evoked IPSPs in both R-Mns and P-Mns with about 10 to 15 msec latencies. By injecting Cl ions into R-Mns or P-Mns, the hyperpolarizing postsynaptic potentials evoked by jaw-opening muscle afferent impulses were reversed to depolarizing potentials. The lingual-IPSPs of hypoglossal motoneurons were concluded to be dependent on increase of Cl conductance. Stimulation of low threshold lingual afferents evoked a reflex discharge in the retractive nerve fibers with a 6.0 msec latency and in the protrusive nerve fibers with a 5.5 msec latency. Inhibition of the linguohypoglossal reflex by stimulation of the jaw-opening muscle afferents was completely removed by an intravenous injection of strychnine (0.1 mg/kg) or picrotoxin (6 mg/kg). It is concluded that the low threshold afferents arising in the jaw-opening muscles are connected to both R-Mns and P-Mns and P-Mns through inhibitory synapses via a polysynaptic pathway.
在麻醉猫中研究了下颌开口肌传入神经与舌下运动核中回缩和前突运动神经元（R-Mns和P-Mns）之间的突触联系。结果发现，刺激下颌开口肌（下颌舌骨肌和二腹肌）产生的低阈值传入神经，可在R-Mns和P-Mns中诱发IPSP，潜伏期约为10至15毫秒。通过向R-Mns或P-Mns中注入氯离子，由下颌开口肌传入冲动诱发的超极化突触后电位可反转去极化电位。得出结论，舌下运动神经元的舌IPSP依赖于氯离子电导的增加。刺激低阈值舌传入神经可在回缩神经纤维中诱发潜伏期为6.0毫秒的反射性放电，在前突神经纤维中诱发潜伏期为5.5毫秒的反射性放电。静脉注射士的宁（0.1毫克/千克）或印防己毒素（6毫克/千克）可完全消除刺激下颌开口肌传入神经对舌-舌下反射的抑制作用。得出结论，下颌开口肌产生的低阈值传入神经通过多突触途径经抑制性突触与R-Mns和P-Mns相连。
