Drs. J. Barbosa, Jr. and A. D. Clarizia contributed equally to this work.
Effect of Protein Kinase C Activation on the Release of [3H]Acetylcholine in the Presence of Vesamicol
Article first published online: 18 NOV 2002
Journal of Neurochemistry
Volume 69, Issue 6, pages 2608–2611, December 1997
How to Cite
Barbosa, J., Clarizia, A. D., Gomez, M. V., Romano-Silva, M. A., Prado, V. F. and Prado, M. A. M. (1997), Effect of Protein Kinase C Activation on the Release of [3H]Acetylcholine in the Presence of Vesamicol. Journal of Neurochemistry, 69: 2608–2611. doi: 10.1046/j.1471-4159.1997.69062608.x
- Issue published online: 18 NOV 2002
- Article first published online: 18 NOV 2002
- Resubmitted manuscript received August 20, 1997; accepted August 20, 1997.
- Acetylcholine release;
- Vesicular acetylcholine transporter;
- Synaptic vesicles;
- Protein kinase C
Abstract: The present work tested whether pharmacological activation of protein kinase C (PKC) influences the release of [3H]-acetylcholine ([3H]ACh) synthesized in the presence of vesamicol, an inhibitor of the vesicular acetylcholine transporter (VAChT). Newly synthesized [3H]ACh was released from hippocampal slices by field stimulation (15 Hz) in the absence of vesamicol, but as expected [3H]ACh synthesized during exposure to vesamicol was not released significantly by stimulation. Treatment of slices with the PKC activator phorbol myristate acetate (PMA) decreased the inhibitory effect of vesamicol on [3H]ACh release. The effect of PMA was dose-dependent, was sensitive to calphostin C, a PKC-selective inhibitor, and could not be mimicked by α-PMA, an inactive phorbol ester. PMA did not alter the release of [3H]ACh in the absence of vesamicol, suggesting that the site of PKC action could be related to the VAChT. In agreement with this observation, immunoprecipitation of VAChT from 32P-labeled synaptosomes showed that phosphorylation occurs and that incorporation of 32P in the VAChT protein increases in the presence of PMA. We suggest that PKC alters the output of [3H]ACh formed in the presence of vesamicol and also provide circumstantial evidence for a role of phosphorylation of VAChT in this process.