Pituitary control of BK potassium channel function and intrinsic firing properties of adrenal chromaffin
Pituitary control of BK potassium channel function and intrinsic firing properties of adrenal chromaffin
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DOI：
10.1523/jneurosci.21-10-03429.2001
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发表时间：
2001-05-15
影响因子：
5.3
通讯作者：
McCobb, DP
中科院分区：
文献类型：
--
作者：
Lovell, PV;McCobb, DP
发现下丘脑-垂体-肾上腺皮质（HPA）内分泌应激轴控制嗜铬Slo编码的BK（大钾）通道的选择性剪接决定，提出了HPA激活可能作为调节分泌肾上腺素的肾上腺嗜铬细胞内在电特性的机制。为了验证这一点，我们比较了BK功能特性和细胞兴奋性的嗜铬细胞正常和垂体切除（垂体消融）大鼠。垂体切除术被发现改变BK门控的电压依赖性和动力学，使通道不容易从休息激活。穿孔贴片记录显示动作电位波形和重复放电特性的变化。通过垂体切除术，可以用2秒去极化电流脉冲引起的尖峰的最大数量减少了约50%。结果表明，垂体激素可以通过调节BK通道功能来适应肾上腺释放儿茶酚胺的机制。
The discovery that the hypothalamic-pituitary-adrenocortical (HPA) endocrine stress axis controls an alternative splicing decision in chromaffin Slo-encoded BK (big potassium) channels raised the possibility that activation of the HPA could serve as a mechanism to tune the intrinsic electrical properties of epinephrine-secreting adrenal chromaffin cells. To test this, we compared BK functional properties and cell excitability in chromaffin cells from normal and hypophysectomized (pituitary-ablated) rats. Hypophysectomy was found to alter the voltage dependence and kinetics of BK gating, making channels less accessible for activation from rest. Perforated-patch recordings revealed changes in action potential waveform and repetitive firing properties. The maximum number of spikes that could be elicited with a 2 sec depolarizing current pulse was reduced by similar to 50% by hypophysectomy. The results indicate that pituitary hormones can adapt the mechanics of adrenal catecholamine release by tailoring BK channel function.