—The importance of extracellular choline transport to spontaneous and K+ depolarized release of ACh was studied using mouse brain cortex minces. The results suggest that extracellular choline transport is not essential to spontaneously released ACh but is essential to K+ depolarized ACh release. Similar cumulative amounts of choline and ACh were found in the incubation media following incubation of minces in either Krebs or 35 mm‐K+ Krebs suggesting the same production of free choline during both conditions. Double reciprocal plots of choline accumulation by non‐depolarized cortex minces yield high and low affinity components. Conversely, similar analysis of choline accumulation by depolarized minces yields a single Michaelis constant (68 μm) similar to the low affinity (50 μm) Michaelis constant determined for choline accumulation by non‐depolarized minces. Kinetic analysis of ACh release as a function of extracellular choline concentration during K+ depolarization also yields a Michaelis constant of 68 μm These data suggest a link between choline transport and ACh release during K+ depolarization.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Neurochemistry|
|State||Published - Oct 1975|
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience