Felpel L P
J Neurosci Res. 1977;3(4):289-94. doi: 10.1002/jnr.490030407.
Postsynaptic potentials, evoked by lingual or hypoglossal nerve stimulation, were recorded from hypoglossal motoneurons of the cat with glass microelectrodes. Lingual nerve-evoked inhibitory postsynaptic potentials (LIPSPs) were recorded in 98% of hypoglossal motoneurons. Hypoglossal nerve stimulation caused a hyperpolarizing potential following the antidromic spike in all hypoglossal motoneurons tested. This potential was unaffected by depolarizing or hyperpolarizing currents, could not be evoked at a stimulus strength less than that which was threshold for the antidromic action potential, and did not change in shape or amplitude at stimulus strengths which were above threshold for antidromic invasion. This hyperpolarizing potential was therefore considered to be an afterhyperpolarization. However, hypoglossal nerve-induced inhibitory postsynaptic potentials were recorded from hypoglossal units which had characteristics of interneurons, thus suggesting the presence of afferent fibers in the hypoglossal nerve. The hypoglossal nerve-induced afterhyperpolarization was not affected by strychnine, bicuculline, or picrotoxin. The LIPSP was antagonized by strychnine but unaffected by bicuculline or picrotoxin. The results suggest that inhibition of hypoglossal motoneurons via the lingual nerve is more likely to be mediated by glycine than gamma-aminobutyric acid (GABA) and is therefore similar to the strychnine-sensitive postsynaptic inhibition of spinal motoneurons.
用玻璃微电极从猫的舌下运动神经元记录由舌神经或舌下神经刺激诱发的突触后电位。在98%的舌下运动神经元中记录到了舌神经诱发的抑制性突触后电位（LIPSPs）。在所有测试的舌下运动神经元中，舌下神经刺激在逆向动作电位之后引起一个超极化电位。这个电位不受去极化或超极化电流的影响，在刺激强度低于逆向动作电位阈值时不能诱发，并且在刺激强度高于逆向冲动阈值时其形状和幅度不变。因此，这个超极化电位被认为是一个后超极化电位。然而，从具有中间神经元特征的舌下神经元记录到了舌下神经诱发的抑制性突触后电位，这表明舌下神经中存在传入纤维。舌下神经诱发的后超极化电位不受士的宁、荷包牡丹碱或印防己毒素的影响。LIPSP被士的宁拮抗，但不受荷包牡丹碱或印防己毒素的影响。结果表明，通过舌神经对舌下运动神经元的抑制更可能是由甘氨酸介导的，而不是γ-氨基丁酸（GABA），因此类似于脊髓运动神经元的对士的宁敏感的突触后抑制。
