Calcium efflux and spontaneous activity of frog sinus venosus and isotonic sucrose solution
Bhatnagar, A.; Mehrotra, M.; Tripathi, O.
Indian Journal of Experimental Biology 24(6): 389-394
1986
ISSN/ISBN: 0019-5189 PMID: 3770827 Document Number: 281191
Isolated frog sinus venosus (SV) exhibited spontaneous contractions in isotonic sucrose solution for up to 150 min, indicating prolonged persistence of pacemaker activity of this tissue in the absence of extracellular ions. The change in frequency of contractions of SV and 45Ca retained by and 45Ca-efflux from this tissue were analysed for the initial 60 min exposure to isotonic sucrose solution. The curves for 45Ca-retention by SV in Ringer's and sucrose solutions exhibit a multicompartmental nature and are satisfied by a 3 pool model for the tissue Ca. 45Ca-efflux was greatly reduced, and the pool 3 45Ca was retained longer in electrolyte free solution. Retention of Ca by SV appears to be responsible for the sustenance of its spontaneous activity in isotonic sucrose solution.