Biophysical properties of hypoglossal neurons in vitro: intracellular studies in adult and neonatal rats.
Biophysical properties of hypoglossal neurons in vitro: intracellular studies in adult and neonatal rats.
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舌下神经元的体外生物物理特性：成年和新生大鼠的细胞内研究。
DOI：
10.1152/jappl.1990.69.4.1509
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Getting,PA
中科院分区：
文献类型：
--
作者：
Haddad,GG;Donnelly,DF;Getting,PA
使用成年和新生（小于或等于 12 天）大鼠的脑干切片制剂和细胞内记录来检查舌下 (HYP) 核内神经元的细胞特性。成人舌下神经元的静息膜电位 (Vm) 为 -80 +/- 2 (SE) mV。 Rheobase 为 2.1 +/- 0.4 nA，输入电阻 (RN) 为 20.8 +/- 1.5 M Ω，并在超极化期间下降（“下垂”）。与成年 HYP 细胞相比，新生 HYP 神经元具有显着较低的静息电位 (Vm = -73 +/- 2 mV)、较低的流变碱 (0.7 +/- 0.2 nA) 和较高的 RN (27.6 +/- 3.9 M omega)。由短去极化电流脉冲引起的单动作电位，随后在成人细胞中缓慢后超极化[6.4 +/- 0.3 mV，时间常数 (tc) 31.0 +/- 1.2 ms] 和新生细胞（7.4 +/- 0.2 mV，tc 37.2 +/- 8.2 ms）。长时间的外向电流（2秒）在成人或新生神经元中几乎没有产生尖峰频率适应。去极化之前的超极化脉冲不会延迟尖峰活动的发生。此外，药理学实验表明，HYP神经元具有河豚毒素敏感的Na+电流和延迟的内向整流电流，但没有主要的Ca2+电流。我们得出以下结论。 1) HYP神经元的电生理膜特性在出生后成熟；其中一些发育变化可以归因于体细胞大小和树突生长的增加，但其他变化则不能。 2）与其他脑干神经元（即迷走神经细胞或孤束核细胞）相比，成年HYP神经元不具有主要的Ca2+电流或K+电流，例如A电流和Ca2(+)激活的K+电流。
A brain stem slice preparation from adult and neonatal (less than or equal to 12 days old) rats and intracellular recordings were used to examine the cellular properties of neurons within the hypoglossal (HYP) nucleus. Resting membrane potential (Vm) for adult hypoglossal neurons was -80 +/- 2 (SE) mV. Rheobase was 2.1 +/- 0.4 nA, and input resistance (RN) was 20.8 +/- 1.5 M omega and decreased during the hyperpolarizing period ("sag"). Compared with adult HYP cells, newborn HYP neurons had significantly lower resting potentials (Vm = -73 +/- 2 mV), lower rheobase (0.7 +/- 0.2 nA), and higher RN (27.6 +/- 3.9 M omega). Single action potentials, elicited by short depolarizing-current pulses, were followed by a slow afterhyperpolarization in adult [6.4 +/- 0.3 mV, time constant (tc) 31.0 +/- 1.2 ms] and newborn cells (7.4 +/- 0.2 mV, tc 37.2 +/- 8.2 ms). Prolonged outward current (2 s) produced little spike frequency adaptation in either adult or newborn neurons. Onset of spike activity was not delayed by hyperpolarizing pulses preceding depolarizations. In addition, pharmacological experiments showed that HYP neurons have a tetrodotoxin-sensitive Na+ current and a delayed and an inward rectifier current but no major Ca2+ current. We conclude the following. 1) Electrophysiological membrane properties mature postnatally in HYP neurons; some of these developmental changes can be ascribed to an increase in soma size and dendritic outgrowth but others cannot. 2) Adult HYP neurons, compared with other brain stem neurons (i.e., vagal cells or cells in the nucleus tractus solitarius), are not endowed with major Ca2+ currents or K+ currents such as the A current and the Ca2(+)-activated K+ current.