ALPHA-1-ADRENERGIC AND CHOLINERGIC AGONISTS USE SEPARATE SIGNAL TRANSDUCTION PATHWAYS IN LACRIMAL GLAND
ALPHA-1-ADRENERGIC AND CHOLINERGIC AGONISTS USE SEPARATE SIGNAL TRANSDUCTION PATHWAYS IN LACRIMAL GLAND
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DOI：
10.1152/ajpgi.1992.262.6.g1087
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发表时间：
1992-06-01
影响因子：
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通讯作者：
DARTT, DA
中科院分区：
文献类型：
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作者：
HODGES, RR;DICKER, DM;DARTT, DA
在大鼠眶外泪腺分离的腺泡中比较了 α-1-肾上腺素能激动剂和胆碱能激动剂使用的细胞转导途径。过氧化物酶分泌量是蛋白质分泌量的指标。通过阴离子交换色谱法测量肌醇磷酸盐，通过使用 fura-2 的荧光方法测量细胞内游离 Ca2+ 浓度 ([Ca2+]i)，通过蛋白质结合放射测定法测量细胞腺苷 3',5'-环单磷酸 (cAMP) 水平，并通过 [P-32]ATP 掺入外源底物测量蛋白激酶 C (PKC) 活性。同时添加α-1-肾上腺素能激动剂去氧肾上腺素和胆碱能激动剂卡巴胆碱所刺激的蛋白质分泌是相加的。在1或20分钟的孵育过程中，卡巴胆碱(10(-3) M)显着增加了磷酸肌醇与肌醇的比率，而去氧肾上腺素(10(-5)至10(-2) M)则没有这种效果。与卡巴胆碱 (10(-4) M) 相比，去氧肾上腺素 (10(-3) M) 使 [Ca2+]i 显着增加最多 15 +/- 3 nM，卡巴胆碱 (10(-4) M) 使 [Ca2+] 增加最多 90 +/- 14 nM。去氧肾上腺素(10(-4) M)不增加cAMP水平，去氧肾上腺素(10(-5)至10(-3) M)以浓度依赖性方式降低胞质PKC活性。 Carbachol (10(-3) M) 短暂地导致细胞质 PKC 活性轻微下降。我们的结果表明，α-1-肾上腺素能激动剂和胆碱能激动剂使用单独且不同的途径来刺激泪腺。
The cellular transduction pathways used by alpha-1-adrenergic and cholinergic agonists were compared in isolated acini from rat exorbital lacrimal glands. Peroxidase secretion was the index of protein secretion. Inositol phosphates were measured by anion exchange chromatography, intracellular free Ca2+ concentration ([Ca2+]i) by fluorescence methods using fura-2, cellular adenosine 3',5'-cyclic monophosphate (cAMP) levels by protein binding radioassay, and protein kinase C (PKC) activity by [P-32]ATP incorporation into exogenous substrate. Protein secretion stimulated by simultaneous addition of the alpha-1-adrenergic agonist phenylephrine and the cholinergic agonist carbachol was additive. Carbachol (10(-3) M) significantly increased the ratios of inositol phosphates to inositol during a 1- or 20-min incubation in contrast to phenylephrine (10(-5) to 10(-2) M), which did not. Phenylephrine (10(-3) M) significantly increased the [Ca2+]i by a maximum of 15 +/- 3 nM compared with carbachol (10(-4) M), which increased [Ca2+], to a maximum of 90 +/- 14 nM. Phenylephrine (10(-4) M) did not increase cAMP levels, Phenylephrine (10(-5) to 10(-3) M) decreased cytosolic PKC activity in a concentration-dependent manner. Carbachol (10(-3) M) transiently caused a slight decrease in cytosolic PKC activity. Our results indicate that alpha-1-adrenergic and cholinergic agonists use separate and different pathways to stimulate the lacrimal gland.