Attenuation of morphine withdrawal signs by a GABAB receptor agonist in the locus coeruleus of rats

In the present study, the effects of intra-locus coeruleus (LC) injection of GABA(B) receptor-interacting agents on naloxone-induced withdrawal signs of morphine-dependent rats were examined. The GABA(B) receptor agonist and antagonists were injected 5 min prior to naloxone injection. Baclofen, a GABA(B) receptor agonist, decreased the TWS in a dose-dependent manner but CGP35348, a GABA(B) receptor antagonist, alone had no effect. On the other hand, baclofen effects were reversed by CGP35348. It may be concluded that activation of GABA(B) receptor mechanisms in the LC reduces precipitated withdrawal symptoms from chronic morphine treatment. (C) 2008 Published by Elsevier B.V.