SYNAPTIC MECHANISMS INVOLVED IN THE INSPIRATORY MODULATION OF VAGAL CARDIO-INHIBITORY NEURONS IN THE CAT
SYNAPTIC MECHANISMS INVOLVED IN THE INSPIRATORY MODULATION OF VAGAL CARDIO-INHIBITORY NEURONS IN THE CAT
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DOI：
10.1113/jphysiol.1984.sp015453
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发表时间：
1984-01-01
影响因子：
5.5
通讯作者：
SPYER, KM
中科院分区：
文献类型：
--
作者：
GILBEY, MP;JORDAN, D;SPYER, KM
用电生理和神经药理学方法研究猫疑核迷走神经心脏抑制神经元活动的呼吸调节。所有24个迷走神经传出神经元都有轴突，其传导速度显示为B纤维，并投射到迷走神经的右心分支。在吸气阶段，它们自发产生的同型半胱氨酸(DLH)诱发的活动明显减少，并且都显示出接受压力感受器输入的迹象。电泳法应用DLH常兴奋心脏迷走单核神经元(C.v.m.s)。将乙酰胆碱应用于这些相同的细胞，在15个被测试的神经元中，有12个神经元的放电频率下降。在这12个细胞中，有10个细胞同时应用阿托品可拮抗乙酰胆碱的作用。单独应用阿托品可以增强神经元的放电，特别是在吸气时。从2cv.m.s开始进行稳定的细胞内记录。这些都在吸气时被抑制了。吸入时输入阻力显著下降，注射氯离子使这种超极化波逆转为去极化波，表明这是氯离子介导的抑制性突触后电位(i.p.p.s.)的结果。这些病毒组。在第一阶段呼气时被激活，在第二阶段呼气时表现出弱而可变的抑制波。在神经元输入阻力降低期间，脉搏节律性去极化电位的幅度降低。显然，C.v.ms在吸气后接受兴奋性输入，在吸气时接受强大的抑制性突触输入。这些观察结果对心肺反射的生理学意义进行了讨论。
The respiratory modulation of the activity of vagal cardio-inhibitory neurons of the nucleus ambiguus of the cat was investigated by electrophysiological and neuropharmacological techniques. All 24 vagal efferent neurons studied had axons with conduction velocities indicative of B fibers and projected to the right cardiac branches of the vagus. Their spontaneous of DL-homocysteic acid (DLH)-evoked activity showed a marked reduction during the phase of inspiration and all showed signs of receiving a baroreceptor input. Ionophoretic application of DLH always excited cardiac vagal montoneurons (c.v.m.s.). Application of acetylcholine to these same cells provoked a decrease in firing rate in 12 of the 15 neurons tested. In 10 of these 12 cells simultaneous application of atropine antagonized the effect of acetylcholine. Atropine applied alone enhanced neuronal firing, particularly in inspiration. Stable intracellular recordings were made from 2 c.v.m.s. These were inhibited during inspiration. Input resistance fell markedly during inspiration and injection of Cl reversed this wave of hyperpolarization to a wave of depolarization, indicating that this resulted from Cl-mediated inhibitory post-synaptic potentials (i.p.s.p.s.). These c.v.m.s. were activated during stage I expiration, showed a weak and variable wave of inhibition in stage II expiration. Pulse-rhythmic depolarizing potentials were reduced in their amplitudes during the periods of decreased neuron input resistance. Evidently, c.v.m.s receive an excitatory input during post-inspiration and a powerful inhibitory synaptic input during inspiration. The implications of these observations for the physiology of cardiorespiratory reflexes are discussed.