ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: : Guinea-pig synaptosomes possess two functional pools of 4-aminobutyrate (GABA). One is rapidly labelled by added [I4C]GABA, is steadily released in a Ca2+-independent manner when the Na+ electrochemical potential across the plasma membrane is collapsed, and is depleted by the GABA analogue 2,4-diaminobutyrate (DABA), all of which is consistent with a cytosolic location. A second, noncytosolic compartment only slowly equilibrates with exogenous [14C]GABA, is not depleted by DABA, but can release 350 pmol of endogenous GABA/mg of protein (8% of the total intrasynaptosomal GABA) within 15 s of depolarization in the presence of Ca2+. Ca2+-independent release occurs by thermodynamic reversal of the plasma membrane uptake pathway following artifactually prolonged depolarization, whereas Ca2+-dependent release is consistent with physiological exocytosis from vesicular stores.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1987.tb03424.x
Permalink