Activation of protein kinase C reduces L-type calcium channel activity of GH3 pituitary cells.
Activation of protein kinase C reduces L-type calcium channel activity of GH3 pituitary cells.
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蛋白激酶 C 的激活会降低 GH3 垂体细胞的 L 型钙通道活性。
DOI：
10.1152/ajpcell.1992.262.5.c1211
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Hinkle,PM
中科院分区：
文献类型：
--
作者：
Haymes,AA;Kwan,YW;Arena,JP;Kass,RS;Hinkle,PM
这些研究描述了蛋白激酶C（PKC）激活对GH 3垂体细胞电压敏感性L型Ca ~（2+）通道活性的影响。在BAY K 8644的存在下，45 Ca 2+摄取的速率被刺激大于25倍的去极化;佛波酯12-O-tetradecanoylphorbol 13-acetate（TPA）以浓度依赖性方式将这种反应降低了70%。佛波醇12，13-二丁酸酯（PDBu）在1分钟内抑制去极化诱导的45 Ca 2+摄取，并在1小时后引起几乎最大的减少;其作用是迅速可逆的。TPA降低了高K（+）刺激的细胞内游离钙离子浓度（[Ca 2 +]i）的增加，5分钟时从8.5倍增加到3.2倍，18小时后减少到2.0倍，而不改变对肽激素TRH的峰值[Ca 2 +]i反应。直接使用膜片钳技术的全细胞配置测量的Ca 2+通道电流，下降了平均6.4%，超过5分钟的控制细胞和28.9%时，TPA加入到洗澡介质5分钟。治疗与100 nM TPA 24小时显着降低峰值电流，而不移动的电流-电压关系的峰值。平均峰值Ca 2+通道电流从423降至128 pA，尽管少数细胞似乎完全抵抗。为了确定佛波酯的作用是否是由于PKC的激活，我们测试了几种药物抑制L-通道活性和改变表皮生长因子（EGF）受体（一种已建立的PKC反应）亲和力的效力。（250字处删节）
These studies describe the effect of protein kinase C (PKC) activation on the activity of voltage-sensitive L-type Ca2+ channels of GH3 pituitary cells. The rate of 45Ca2+ uptake was stimulated greater than 25-fold by depolarization in the presence of BAY K 8644; the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) reduced this response by 70% in a concentration-dependent fashion. Phorbol 12,13-dibutyrate (PDBu) inhibited depolarization-induced 45Ca2+ uptake within 1 min and caused a nearly maximal reduction after 1 h; its effects were rapidly reversible. TPA decreased the high K(+)-stimulated increase in intracellular free calcium ion concentration ([Ca2+]i) from 8.5- to 3.2-fold by 5 min and to 2.0-fold after 18 h without altering the peak [Ca2+]i response to the peptide hormone TRH. Ca2+ channel current, measured directly using the whole cell configuration of the patch-clamp technique, declined an average of 6.4% over 5 min for control cells and 28.9% when TPA was added to the bathing medium for 5 min. Treatment with 100 nM TPA for 24 h dramatically reduced peak current without shifting the peak of the current-voltage relationship. The mean peak Ca2+ channel current was reduced from 423 to 128 pA, although a few cells seemed completely resistant. To determine whether the effects of phorbol esters were due to the activation of PKC we tested the potency of several drugs to inhibit L-channel activity and to shift the affinity of the epidermal growth factor (EGF) receptor, an established PKC response.(ABSTRACT TRUNCATED AT 250 WORDS)