Abstract
Using a rapid-quench method to measure 45Ca 2+ uptake into PC12 cells in suspension, we have studied basal, carbachol-stimulated and K 1-induced Ca 2+ uptake under control conditions ([Na +] o = 130 mM) and in the presence of acutely lowered extracellular sodium concentration ([Na +] o = 65 mM). Acute reduction of [Na +] o stimulates basal and K +-evoked Ca 2+ uptake, but reduces net carbachol-stimulated uptake. Since total Ca 2+ uptake measured in the presence of carbachol under control and low [Na +] o conditions is unchanged, the reduction in carbachol-stimulated uptake is due to the increase in basal uptake induced by low [Na +] o. These results reconcile apparently conflicting data regarding a specific Na + requirement for nicotinic acetylcholine receptor-mediated responses in PC12 cells and adrenal chromaffin cells and suggest a mechanism for loss of nicotinic acetylcholine receptor (nAChR) responsiveness to agonists under low Na + conditions.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
