Fleming N, Bilan P T, Graham K W
J Dent Res. 1984 Aug;63(8):1022-7. doi: 10.1177/00220345840630080101.
The effects of the undecapeptide, substance P(SP), on the secretion of mucin and proteolytic enzymes from dispersed cells of the rat submandibular gland were studied. The peptide, at a concentration of 1 X 10(-7) M, stimulated the release of 31.9 +/- 3.0% (mean +/- SEM) of intracellular mucin over 40 min, compared with 12.5 +/- 1.5% in untreated controls (p less than 0.01). This effect was duplicated by the homologous peptides, physalaemin, and eledoisin-related peptide. Substance P action was not affected by pre-incubation of cells with phentolamine or propranolol and was therefore independent of adrenergic stimulation. Furthermore, SP did not enhance the intracellular concentrations of cyclic AMP or cyclic GMP, confirming that cyclic nucleotides were not involved in its stimulus-secretion coupling mechanism. The isoproterenol-stimulated secretion of mucin from dispersed cells was reduced to 75.7% of the normal response (p less than 0.01) after a brief exposure to SP. This inhibitory effect was probably mediated by intracellular events rather than by direct effects on cell surface receptors. However, mucin release after treatment with SP followed by norepinephrine (NE) was 161% of that caused by NE alone (p less than 0.01) and may reflect an additive response to the independent stimulation of SP and NE receptors. Substance P and related peptides had no effect on arginine esterase secretion in the experimental model, although a response was elicited by alpha- and beta-adrenergic agonists. It is, therefore, proposed that serous cells of the granular convoluted tubule in the rat submandibular gland lack substance P receptors.
研究了十一肽P物质（SP）对大鼠下颌下腺分散细胞黏蛋白和蛋白水解酶分泌的影响。该肽浓度为1×10⁻⁷ M时，在40分钟内刺激细胞内黏蛋白释放31.9±3.0%（平均值±标准误），而未处理的对照组为12.5±1.5%（p＜0.01）。同源肽、physalaemin和eledoisin相关肽也有同样的作用。用酚妥拉明或普萘洛尔预孵育细胞不影响P物质的作用，因此其作用与肾上腺素能刺激无关。此外，SP不会提高细胞内环磷酸腺苷（cAMP）或环磷酸鸟苷（cGMP）的细胞内浓度，这证实环核苷酸不参与其刺激-分泌偶联机制。短暂暴露于SP后，异丙肾上腺素刺激分散细胞分泌黏蛋白的量降至正常反应的75.7%（p＜0.01）。这种抑制作用可能是由细胞内事件介导的，而不是对细胞表面受体的直接作用。然而，先用SP处理再用去甲肾上腺素（NE）处理后，黏蛋白释放量是单独使用NE时的161%（p＜0.01），这可能反映了对SP和NE受体独立刺激的累加反应。在实验模型中，P物质及相关肽对精氨酸酯酶分泌无影响，而α和β肾上腺素能激动剂可引发反应。因此，有人提出大鼠下颌下腺颗粒曲管的浆液细胞缺乏P物质受体。
