Low levels of ethanol stimulate and high levels decrease phosphorylation in microtubule-associated proteins in rat brain: An in vitro study

Citation
B. Ahluwala et al., Low levels of ethanol stimulate and high levels decrease phosphorylation in microtubule-associated proteins in rat brain: An in vitro study, ALC ALCOHOL, 35(5), 2000, pp. 452-457
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Clinical Psycology & Psychiatry","Neurosciences & Behavoir
Journal title
ALCOHOL AND ALCOHOLISM
ISSN journal
0735-0414 → ACNP
Volume
35
Issue
5
Year of publication
2000
Pages
452 - 457
Database
ISI
SICI code
0735-0414(200009/10)35:5<452:LLOESA>2.0.ZU;2-H
Abstract
Phosphorylation and dephosphorylation of proteins associated with microtubu les (MAPs) modulate the functional properties of microtubules (MT). A study was designed to test the hypothesis that ethanol at pharmacologically rele vant levels affects phosphoryIation of MAPs. Low (6, 17, 24, and 48 nM) and high (96, 384, and 768 mM) levels of ethanol were used in the study. MT pr epared from rat brain by successive cycles of assembly-disassembly were fou nd to contain two high molecular weight proteins (MAP2 and MAP1). tubulin. and 70-kDa neurofilament. The kinase activity was determined using [gamma P -32]ATP as a phosphate donor. The results showed that ethanol primarily sti mulated MAP2 phosphorylation. Low levels of ethanol stimulated, whereas hig h levels decreased. the kinase activity MAP1 was phosphorylated to a lesser extent. 70-kDa neurofilament and tubulin were phosphorylated, however, the dose dependent biphasic effect of ethanol on phosphorylation was not found in these cytoskeleton proteins. To determine whether the ethanol-induced k inase activity was cAMP-dependent, the catalytic subunit of cAMP-dependent protein kinase was isolated, purified, and kinase activity was determined w ith and without ethanol. The results showed that cAMP was not involved in e thanol-induced kinase activity. We conclude that ethanol predominantly stim ulates phosphorylation of MAP2 in a dose-dependent manner.