| Autor: |
Nikushkin, E. V., Antonikov, I. M., Glebov, R. N. |
| Zdroj: |
Bulletin of Experimental Biology and Medicine; March 1980, Vol. 89 Issue: 3 p295-297, 3p |
| Abstrakt: |
The transmembrane potential (TMP) of synaptosomes isolated from the rat cerebral cortex was studied with the aid of 1-anilinonaphthalene-8-sulfonate (ANS). Addition of valinomycin to the synaptosomes was accompanied by an increase in the intensity of fluorescence of the probe at 464 nm (?exc = 365 nm), which is interpreted as reflecting hyperpolarization of the synaptosomal membranes. A decrease in the K+ gradient on the synaptosomal membrane (a decrease in TMP), achieved by preincubation of the synaptosomes with ouabain (1 mM) or an increase in the concentration of extrasynaptosomal K+ from 5 to 20 mM appreciably reduced the effect of valinomycin. Valinomycin had no effect on synaptosomes exposed to osmotic shock. It is suggested that valinomycin-induced changes in the intensity of fluorescence of ANS be used as a test of preservation of the K+ gradient (the presence of a TMP) by synaptosomal preparations, i.e., of the active state of the synaptosomes. |
| Databáze: |
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