Murakami M, Yoshimura K, Sugiya H, Seo Y, Loffredo F, Riva A
Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Eur J Morphol. 2002 Oct;40(4):203-7. doi: 10.1076/ejom.40.4.203.16691.
Transport of electrolytes/water and exocytosis are activated by elevation of the cytosolic Ca(2+) concentration and are potentiated by elevation of cytosolic cyclic AMP. To correlate mucin and fluid secretion with morphological changes, rat submandibular glands were vascularly perfused and the fluid secretion and N-acetylgalactosamine in the saliva were measured during stimulation with various concentrations of carbachol (CCh) and/or isoproterenol (ISP). Single stimulation with 1 microM CCh induced a transient increase of N-acetyl galactosamine followed by a decline to a low level during sustained stimulation. The overload of 1 microM ISP increased secretion of N-acetyl galactosamine to a higher sustained level of 40-50 microg/g-min. However, at 1 microM CCh, fluid secretion was maintained at the same level during stimulation and even overload of 1 microM ISP did not significantly affect its level, whereas addition of 0.5 microM ISP to the gland stimulated with 0.1 microM CCh increased fluid secretion. Morphological observation was carried out by HRSEM and TEM. Combination of CCh and ISP in different concentrations resulted in distinctive morphological changes which reflect fluid secretion and mucin secretion. The kinetics of ATP and creatine phosphate (PCr) were measured using P-31 NMR, which indicated that the potentiation of fluid secretion is limited under a higher level of CCh stimulation due to a limited energy supply.
电解质/水的转运和胞吐作用由胞质Ca(2+)浓度升高激活，并因胞质环磷酸腺苷升高而增强。为了将黏蛋白和液体分泌与形态学变化相关联，对大鼠下颌下腺进行血管灌注，并在不同浓度的卡巴胆碱（CCh）和/或异丙肾上腺素（ISP）刺激期间测量唾液中的液体分泌和N-乙酰半乳糖胺。用1 microM CCh单次刺激会导致N-乙酰半乳糖胺短暂增加，随后在持续刺激期间下降至低水平。1 microM ISP的过量会使N-乙酰半乳糖胺的分泌增加到40 - 50微克/克-分钟的更高持续水平。然而，在1 microM CCh时，刺激期间液体分泌维持在相同水平，即使1 microM ISP过量也不会显著影响其水平，而向用0.1 microM CCh刺激的腺体中添加0.5 microM ISP会增加液体分泌。通过高分辨率扫描电子显微镜（HRSEM）和透射电子显微镜（TEM）进行形态学观察。不同浓度的CCh和ISP组合导致了独特的形态学变化，反映了液体分泌和黏蛋白分泌。使用磷-31核磁共振（P-31 NMR）测量ATP和磷酸肌酸（PCr）的动力学，结果表明由于能量供应有限，在较高水平的CCh刺激下，液体分泌的增强受到限制。
