Acute ethanol administration rapidly increases phosphorylation of conventional protein kinase C in specific mammalian brain regions in vivo.
BACKGROUND
Protein kinase C (PKC) is a family of isoenzymes that regulate a variety of functions in the central nervous system including neurotransmitter release, ion channel activity, and cell differentiation. Growing evidence suggests that specific isoforms of PKC influence a variety of behavioral, biochemical, and physiological effects of ethanol in mammals. The purpose of this study was to determine whether acute ethanol exposure alters phosphorylation of conventional PKC isoforms at a threonine 674 (p-cPKC) site in the hydrophobic domain of the kinase, which is required for its catalytic activity.


METHODS
Male rats were administered a dose range of ethanol (0, 0.5, 1, or 2 g/kg, intragastric) and brain tissue was removed 10 minutes later for evaluation of changes in p-cPKC expression using immunohistochemistry and Western blot methods.


RESULTS
Immunohistochemical data show that the highest dose of ethanol (2 g/kg) rapidly increases p-cPKC immunoreactivity specifically in the nucleus accumbens (core and shell), lateral septum, and hippocampus (CA3 and dentate gyrus). Western blot analysis further showed that ethanol (2 g/kg) increased p-cPKC expression in the P2 membrane fraction of tissue from the nucleus accumbens and hippocampus. Although p-cPKC was expressed in numerous other brain regions, including the caudate nucleus, amygdala, and cortex, no changes were observed in response to acute ethanol. Total PKCgamma immunoreactivity was surveyed throughout the brain and showed no change following acute ethanol injection.


CONCLUSIONS
These results suggest that ethanol rapidly promotes phosphorylation of cPKC in limbic brain regions, which may underlie effects of acute ethanol on the nervous system and behavior.
Wilkie
Mary Beth
MB
Bowles Center for Alcohol Studies, Department of Psychiatry, School of Medicine University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA.
Besheer
Joyce
J
Kelley
Stephen P
SP
Kumar
Sandeep
S
O'Buckley
Todd K
TK
Morrow
A Leslie
AL
Hodge
Clyde W
CW
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D015153:Blotting, Western; D001921:Brain / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D007150:Immunohistochemistry; D008032:Limbic System / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010766:Phosphorylation / Q000187:drug effects*; D020033:Protein Isoforms / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D014018:Tissue Distribution
D020033:Protein Isoforms; D000431:Ethanol; D011493:Protein Kinase C