Intracellular [Ca 2+] and K + and Cl − efflux responses in submandibular cells of neonatal and adult rats

The effects of graded doses (5 × 10 −8 to 10 −5 ) acetylcholine on intracellular Ca 2+ and on 86Rb and 36Cl efflux were compared in submandibular cell clusters of 1 and 7 day-old and adult rats. Initial Ca 2+ peaks were similar at agonists concentrations lower than 10 −7 M but the release of Rb + and Cl − were smaller in cells of young animals.At higher agonist concentrations, Ca 2+ peaks were higher in immature cells; however, initial Cl − (but not Rb +) efflux was similar to that of mature cells. Plateau Ca 2+ levels were independent of age and agonist concentrations but the content of Cl − and Rb + varied greatly and differences between age groups were less evident. These data confirm a dissociation between intracellular Ca 2+ levels and Ca 2+-mediated ion transport in immature salivary cells.