Gap junctional intercellular communication and salivary secretion of amylase and calcein in rat parotid glands

Secretion of amylase and calcein from parotid acini was compared with those from free acinar cells to clarify the role of gap junctional communication in the salivary secretion from rat parotid glands. Release of amylase was stimulated by isoproterenol(IPR) and dibutyryl cyclic AMP(dbcAMP), and slightly stimulated by carbachol(CCh) and A23187. Release of a fluorescent dye, calcein, loaded in acinar cells was enhanced by CCh and A23187. Amylase release by IPR from acini was greater than that from free acinar cells. In contrast, calcein release by CCh from acini was less than that from free acinar cells. These results suggest that gap junctional intercellular communication in rat parotid glands might enhance the secretion of amylase induced by IPR and might suppress the secretion of calcein induced by CCh.