Abstract
Synaptosomes isolated from sheep brain cortex accumulate Ca 2+, Sr 2+ and Mg 2+ when incubated in isosmotic sucrose media containing 5 mM of either of these cations. The maximal levels of cations retained per mg of protein are 100 nmol of Ca 2+, 85 nmol of Mg 2+ and 80 nmol of Sr 2+. The loss of Ca 2+ or Sr 2+ from the preloaded synaptosomes is increased by monovalent cations in the following order: Na +> K + > Li +> choline, whereas for the loss of Mg 2+ this order is different: K + > Na + > Li ∼ choline. The efflux of Ca 2+ or Sr 2+ induced by monovalent cations decreases as the temperature is lowered and it is nearly abolished at 0°C, whereas the efflux of Mg 2+ is much less influenced by temperature. The results suggest that the mechanism of exchange of Ca 2+ for Na + in synaptosomes operates similarly for Sr 2+, but not for Mg 2+.
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.
