Demeneix B A, Taleb O, Loeffler J P, Feltz P
Neuroscience. 1986 Apr;17(4):1275-85. doi: 10.1016/0306-4522(86)90094-1.
A primary culture of porcine pars intermedia cells with particularly high yields has been developed. The cells, grown in monolayers, secrete the pro-opiomelanocortin-derived peptide alpha-melanocyte-stimulating hormone over several weeks. The patch-clamp technique has been used to demonstrate the presence of gamma-aminobutyrateA (GABAA) receptors on the cells. GABA or the selective GABAA receptor agonist isoguvacine produced a depolarizing increase in chloride conductance that desensitized rapidly. The response was antagonized by bicuculline and by the aminopyridazine derivative of GABA (SR 95103), a novel GABAA receptor antagonist. The effects of specific agonists for each receptor were tested on peptide release from cells maintained in a perfusion system. Isoguvacine (10 microM) potentiated Ba2+-evoked release of alpha-melanocyte-stimulating hormone, whereas (-)-baclofen (50 microM) decreased both basal and stimulated hormone release. This negative effect on peptide secretion was reproduced when GABA (50 microM) was perfused in the presence of bicuculline (10 microM) to block GABAA receptor activation. The possible mechanisms underlying these GABAA and GABAB effects on stimulus-secretion coupling in this neuroendocrine model are discussed.
已经建立了一种产量特别高的猪垂体中间部细胞原代培养方法。这些细胞以单层生长，在数周内分泌源自阿片促黑素皮质素原的肽α-黑素细胞刺激素。膜片钳技术已被用于证明这些细胞上存在γ-氨基丁酸A（GABAA）受体。GABA或选择性GABAA受体激动剂异鹅去氧胆酸会使氯离子电导产生去极化增加，且这种增加迅速脱敏。该反应被荷包牡丹碱和一种新型GABAA受体拮抗剂GABA的氨基哒嗪衍生物（SR 95103）所拮抗。对每种受体的特异性激动剂对维持在灌注系统中的细胞的肽释放的影响进行了测试。异鹅去氧胆酸（10微摩尔）增强了钡离子诱发的α-黑素细胞刺激素释放，而（-）-巴氯芬（50微摩尔）则降低了基础和刺激状态下的激素释放。当在存在荷包牡丹碱（10微摩尔）以阻断GABAA受体激活的情况下灌注GABA（50微摩尔）时，再现了对肽分泌的这种负面影响。本文讨论了在这个神经内分泌模型中，这些GABAA和GABAB对刺激-分泌偶联作用的潜在机制。
