Fluid secretion and electrical properties of pancreatic acini of Syrian Golden hamster.

Abstract

Mechanisms of electrolyte and fluid secretion in the hamster pancreatic acini were investigated by measurements of fluid and amylase secretion in vivo and in vitro, and membrane potential and resistance in vitro. Unlike mouse and rat pancreas the hamster pancreas secreted only a small amount of juice in response to acinar stimulants such as acetylcholine (ACh) and caerulein. The mean resting potential was -62 mV and the mean resting input resistance was 29 M omega. Ionophoretic application of ACh evoked membrane depolarization accompanied by a reduction in input resistance. The reversal potential for this ACh-evoked depolarization (EACh) was -11 mV. The EACh was shifted by changing extracellular K, Na and Cl concentration in a similar way to that of mouse pancreatic acinar cells. The relative permeability and current for K, Na and Cl at the EACh calculated by using the Goldman-Hodgkin-Katz equations were PK/PNa/PCl = 1/0.9/0.43 and IK/INa/ICl = 1/1.4/0.4 respectively (In the mouse Pk/PNa/PCl = 1/1.2/5 and Ik/INa/ICl = 1/2.3/1.3, Petersen et al. 1981). The results indicate that mechanisms of electrolyte and fluid secretion in hamster pancreatic acini are qualitatively similar to those in the mouse and rat pancreas. The less permeability of the acinar cell membrane to Cl ions in the hamster than in the mouse and rat appears to be associated with the fact that the acinar stimulant evokes a far smaller amount of fluid secretion in this species than in the mouse and rat.