[Effect of extracellular ATP on the characteristics of synaptosomes from the rat cerebral cortex]

The extracellular ATP, Ca2+, Mg2+, ATP-Ca2+ and ATP + Mg2+ affect the optical density (at 520 nm) and turbidity spectra in suspensions of light and heavy synaptosomes and in mitochondria prepared from rat cerebral cortex. The properties of the light synaptosomes are associated only with their volume changes; the heavy synaptosomes and mitochondria also change their refractive indices. These results could be interpreted by structural (conformational) rearrangements occurring in membranes under such conditions. A support for this assumption was found in the studies on the spin-labeled synaptosomes.