Elevated synaptophysin I in the prefrontal cortex of human chronic alcoholics.
Convergent lines of evidence suggest potentiation of glutamatergic synapses after chronic ethanol exposure, and indicate that the presynaptic effect hereof is on modulators of synaptic strength rather than on executors of glutamate release. To address this hypothesis in the context of ethanol dependence in humans, we used semiquantitative immunoblotting to compare the immunoreactivities of synaptophysin I, syntaxin 1A, synaptosome-associated protein 25, and vesicle-associated membrane protein in the prefrontal and motor cortices between chronic alcoholics and control subjects. We found a region-specific elevation in synaptophysin I immunoreactivity in the prefrontal cortex of alcoholics, but detected no significant differences between the groups in the immunoreactivities of the other three proteins. Our findings are consistent with an effect of repeated ethanol exposure on modulators of synaptic strength but not on executors of glutamate release, and suggest a role for synaptophysin I in the enduring neuroplasticity in the prefrontal cortical glutamate circuitry that is associated with ethanol dependence.
Henriksson
Richard
R
Experimental Alcohol and Drug Dependence Research, Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden. richard.henriksson@ki.se
Kuzmin
Alexander
A
Okvist
Anna
A
Harper
Clive
C
Sheedy
Donna
D
Garrick
Therese
T
Yakovleva
Tatjana
T
Bakalkin
Georgy
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000437:Alcoholism / Q000378:metabolism* / Q000503:physiopathology; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000378:metabolism* / Q000502:physiology; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D017397:Prefrontal Cortex / Q000737:chemistry / Q000378:metabolism*; D016708:Synaptophysin / Q000096:biosynthesis / Q000378:metabolism* / Q000502:physiology
D008562:Membrane Glycoproteins; D016708:Synaptophysin; C100756:SYPL1 protein, human; D018698:Glutamic Acid