Role of nucleus accumbens μ opioid receptors in the effects of morphine on ERK1/2 phosphorylation

Rationale Despite the critical role attributed to phosphorylated extracellular signal regulated kinase (pERK1/2) in the nucleus accumbens (Acb) in the actions of addictive drugs, the effects of morphine on ERK1/2 phosphorylation in this area are still controversial.