A Region-Specific Increase in Gαq and Gα 11 Proteins in Brains of Rats during Cocaine Withdrawal

Gonzalo A. Carrasco, Yahong Zhang, Katerina J. Damjanoska, Deborah N. D'Souza, Francisca Garcia, George Battaglia, Nancy A. Muma, Louis D. Van De Kar

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22 Scopus citations


Serotonin 2A (5-HT2A) receptor-mediated increases in plasma hormone levels become supersensitive after 42 h of withdrawal from cocaine treatment. The present study investigated which components of the 5-HT 2A receptor signaling system are associated with this supersensitivity. Rats were injected daily for 14 days with either saline or cocaine (15 mg/kg i.p.) twice a day or were injected using a "binge" protocol (three injections per day, 1 h apart). Rats were sacrificed 2 or 7 days after the last cocaine injection, and the levels of membrane and cytosol-associated 5-HT2A receptors, Gαq, Gα11, regulators of G protein signaling (RGS)4, and RGS7 proteins were assayed in the hypothalamic paraventricular nucleus, amygdala, and frontal cortex using Western blot analysis. Two days of withdrawal from cocaine, administered twice a day or using a binge protocol, produced an increase in membrane-associated Gαq and Gα11 proteins in the paraventricular nucleus and the amygdala (but not in the frontal cortex). This effect was reversible after 7 days of withdrawal. The protein levels of the 5-HT2A receptor, Gαz protein, and RGS4 or RGS7 proteins were not altered by cocaine withdrawal in any of the above-mentioned brain regions. These findings suggest that the supersensitivity of the 5-HT2A receptors, during withdrawal from chronic cocaine, is associated with an increase in membrane-associated Gαq and Gα11 proteins and not with changes in the expression of 5-HT2A receptors.

Original languageEnglish (US)
Pages (from-to)1012-1019
Number of pages8
JournalJournal of Pharmacology and Experimental Therapeutics
Issue number3
StatePublished - Dec 2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Pharmacology


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