Postnatal development of inhibitory synaptic transmission in the rostral nucleus of the solitary tract
Postnatal development of inhibitory synaptic transmission in the rostral nucleus of the solitary tract
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DOI：
10.1152/jn.2001.85.5.2203
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发表时间：
2001-05-01
影响因子：
2.5
通讯作者：
Bradley, RM
中科院分区：
文献类型：
--
作者：
Grabauskas, G;Bradley, RM
为探讨孤束头侧核(RNST)抑制性突触活动的生后发展，在出生后0-7天(P0-7)、P8-14、P15-21、P22-30和P>；55岁五个年龄组的大鼠上作了全细胞和Granicidin穿孔膜片钳记录。用谷氨酸受体阻断法研究了发育中的RNST神经元在脑片上的被动膜特性以及单个和强直刺激诱发的抑制性突触后电位(IPSP)的电生理和药理学特性。在出生后第1周，RNST神经元的静息膜电位、自发活动、输入电阻和神经细胞膜时间常数发生了显著变化。虽然所有记录的IPSP都是超极化的，但在发育过程中，单一刺激休克诱发的IPSP的上升和衰减时间常数减小，对GABA受体拮抗剂甲基荷包牡丹碱(BMI)的抑制反应-浓度函数左移。在P0-7和P8-14中，IPSP有一个对BMI不敏感的成分，对印防己毒素敏感，这表明GABA(C)受体的瞬时表达。电刺激可引起RNST抑制性突触传递的短期和长期变化。对于P0-7和P8-14动物，强直刺激导致持续的超极化，并在强直刺激终止后维持一段时间。相比之下，强直刺激P15-21和老年动物的神经元会导致超极化，但这种超极化并不持续，而是以指数时间过程衰减到更正的水平。在所有年龄段的神经元中，强直刺激导致单次刺激休克诱发的IPSP增强的比例接近50%。RNST抑制性突触传递的这些发育变化可能对大鼠味觉系统在味觉偏好和厌恶成熟的早期发育过程中突触活动的形成起重要作用。
To explore the postnatal development of inhibitory synaptic activity in the rostral (gustatory) nucleus of the solitary tract (rNST), whole cell and gramicidin perforated patch-clamp recordings were made in five age groups of rats [postnatal day 0-7 (P0-7), P8-14, P15-21, P22-30, and P>55]. The passive membrane properties of the developing rNST neurons as well as the electrophysiological and pharmacological characteristics of single and tetanic stimulus-evoked inhibitory postsynaptic potentials (IPSPs) were studied in brain slices under glutamate receptor blockade. During the first postnatal weeks, significant changes in resting membrane potential, spontaneous activity, input resistance, and neuron membrane time constant of the rNST neurons occurred. Although all the IPSPs recorded were hyperpolarizing, the rise and decay time constants of the single stimulus shock-evoked IPSPs decreased, and the inhibition response-concentration function to the gamma -aminobutyric acid (GABA) receptor antagonist bicuculline methiodide (BMI) shifted to the left during development. In P0-7 and P8-14, but not in older animals, the IPSPs had a BMI-insensitive component that was sensitive to block by picrotoxin, suggesting a transient expression of GABA(C) receptors. Tetanic stimulation resulted in both short- and long-term changes of inhibitory synaptic transmission in the rNST. For P0-7 and P8-14 animals tetanic stimulation resulted in a sustained hyperpolarization that was maintained for some time after termination of the tetanic stimulation. In contrast, tetanic stimulation of neurons in P15-21 and older animals resulted in hyperpolarization that was not sustained but decayed back to a more positive level with an exponential time course. Tetanic stimulation resulted in potentiation of single stimulus shock-evoked IPSPs in similar to 50% of neurons in all age groups. These developmental changes in inhibitory synaptic transmission in the rNST may play an important role in shaping synaptic activity in early development of the rat gustatory system during a time of maturation of taste preferences and aversions.