1. A two-micro-electrode voltage-clamp technique was applied to a study of the resting properties of mouse pancreatic acinar cell membranes and the action of acetylcholine (ACh). 2. The resting voltage-current relation was linear. The specific membrane resistance was calculated to be about 10 k omega cm2. This value was doubled after removal of Cl from the tissue bath superfusion solution. 3. At a holding potential equal to the spontaneous resting potential (about -35 mV) micro-ionophoretic ACh application evoked inward current. Reversal of the polarity of the ACh-evoked current occurred at about - 15 mV. 4. The voltage dependence of the ACh-evoked current displayed inward rectification. This inward rectification could not be accounted for by the constant field equation. 5. The dose-response curves for ACh-evoked inward current were compared in the same units with dose-response curves for ACh-evoked depolarization. Half-maximal depolarization was consistently obtained at a lower dose of ACh than half-maximal inward current. 6. During steady-state exposure of the pancreatic tissue segments to Cl-free sulphate solution the ACh reversal potential was about + 10 mV and the voltage-current relationship for the ACh-controlled channels showed inward rectification. Removal of external Na from the Cl-free solution virtually abolished ACh-evoked inward current. 7. The resting pancreatic acinar cell membrane is electrically inexcitable. The relative permeabilities of the major monovalent ions appears to be PC1/PNa/PK = 2/0.23/1. The ACh-evoked inward current is largely carried by Na. Dose-response curves for ACh-evoked depolarization and inward current in the same acinar units are different, in such a way that the depolarization response saturates at lower ACh concentrations than the current response.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.