Secretory and radioligand binding studies on muscarinic receptors in bovine and feline chromaffin cells.
Secretory and radioligand binding studies on muscarinic receptors in bovine and feline chromaffin cells.
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牛和猫嗜铬细胞中毒蕈碱受体的分泌和放射性配体结合研究。
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
M. J. Hidalgo
中科院分区：
文献类型：
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作者：
J. J. Ballesta;R. Borges;A. G. García;M. J. Hidalgo
1.毒蕈碱激动剂增强了从灌注的猫肾上腺释放的儿茶酚胺，效力的相对顺序如下：乙酰甲胆碱大于氧震颤素大于McN-A-343大于毛果芸香碱大于氨甲酰胆碱大于毒蕈碱。由于连续在线电化学检测系统用于监测儿茶酚胺释放，因此可以在比先前报告低得多的浓度（1 - 10 μ M）和短得多的刺激时间（3 - 30 s）内获得该序列。2.所有毒蕈碱激动剂优先使用分泌的肾上腺素而不是去甲肾上腺素。乙酰甲胆碱在猫肾上腺中引起持续的非脱敏反应，在Ca 2+去除后立即下降至基础分泌水平：在Ca 2+恢复后，分泌恢复至先前的平台期。3.除了引起直接的分泌反应，低浓度的乙酰甲胆碱，毛果芸香碱，氨甲酰胆碱或muscarine明显增强猫肾上腺分泌反应引起的尼古丁脉冲（2 μ M，30秒）或高K+（17.7 mM，30秒）。4. [3 H]苯甲酸奎宁啶酯（QNB）与猫肾上腺髓质膜特异性结合，具有饱和双相曲线，表明单个结合位点，KD为23 pM，Bmax为67 fmol（mg蛋白）-1。阿托品优先取代哌仑西平表明结合位点与M2型毒蕈碱受体相关。5.乙酰甲胆碱（3 - 300 μ M）不会增强灌注的牛完整肾上腺或灌注的嗜铬细胞的自发性儿茶酚胺释放。药物也没有影响分泌引起的二甲基苯基哌嗪（10 μ M为3秒）或K+（35 mM为3秒）从分离的灌流牛肾上腺嗜铬细胞。6. [3 H]QNB与纯化的牛肾上腺髓质质膜结合，KD为29 pM，Bmax为89 fmol（mg蛋白质）-1。哌仑西平置换表明存在两个结合位点（希尔系数= 0.64），Ki 1为39 nM，Ki 2为2734 nM。7.由于离子载体A23187增强了牛和猫肾上腺中K（+）诱发的分泌，因此似乎毒蕈碱刺激诱导的类似胞质Ca 2+升高可能构成了引起分泌反应本身以及烟碱或高K+刺激诱发的儿茶酚胺释放增强的潜在机制。然而，就毒蕈碱诱发效应而言，尚不清楚为什么牛嗜铬细胞的行为与猫嗜铬细胞不同。（摘要截短至400字）
1. Muscarinic agonists enhanced catecholamine release from perfused cat adrenal glands with the following relative order of potencies: methacholine greater than oxotremorine greater than McN‐A‐343 greater than pilocarpine greater than bethanechol greater than muscarine. Because a continuous online electrochemical detection system was used to monitor catecholamine release, this sequence could be obtained at concentrations much lower (1‐10 microM) and during much shorter stimulation times (3‐30 s) than in previous reports. 2. All muscarinic agonists used secreted adrenaline preferentially over noradrenaline. Methacholine evoked a sustained, non‐desensitizing response in the cat adrenal, which declined to basal levels of secretion immediately after Ca2+ removal: upon Ca2+ restoration secretion was restored to the previous plateau. 3. In addition to evoking a direct secretory response, low concentrations of methacholine, pilocarpine, bethanechol or muscarine clearly potentiated cat adrenal secretory responses evoked by pulses of nicotine (2 microM for 30 s) or high K+ (17.7 mM for 30 s). 4. [3H]Quinuclydinyl benzylate (QNB) specifically bound to cat adrenomedullary membranes with a saturating monophasic curve, suggesting a single binding site with a KD of 23 pM and a Bmax of 67 fmol (mg protein)‐1. Preferential displacement by atropine over pirenzepine suggests that the binding site is associated to a M2‐type muscarinoceptor. 5. Methacholine (3‐300 microM) did not enhance the spontaneous catecholamine release from perfused bovine intact adrenal glands or superfused chromaffin cells. Neither did the drug affect secretion evoked by dimethylphenylpiperazinium (10 microM for 3 s) or K+ (35 mM for 3 s) from isolated superfused bovine adrenal chromaffin cells. 6. [3H]QNB bound to purified bovine adrenomedullary plasma membranes with a KD of 29 pM and a Bmax of 89 fmol (mg protein)‐1. Displacement by pirenzepine suggests the presence of two binding sites (Hill coefficient = 0.64) with Ki1 of 39 nM and Ki2 of 2734 nM. 7. Because the ionophore A23187 enhanced K(+)‐evoked secretion in both, bovine and cat adrenals, it seems that a similar cytosolic Ca2+ rise induced by muscarinic stimulation might constitute the underlying mechanism both to cause a secretory response per se as well as the potentiation of catecholamine release evoked by nicotinic or high K+ stimulation. However, it is unclear why the bovine behaves differently from the feline chromaffin cell as far as the muscarine‐evoked effects are concerned.(ABSTRACT TRUNCATED AT 400 WORDS)
猫肾上腺髓质对钾和尼古丁的分泌反应失活。
DOI：
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发表时间：
1982
期刊：
The Journal of pharmacology and experimental therapeutics
影响因子：
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作者：
Schiavone,MT;Kirpekar,SM
通讯作者：
Kirpekar,SM