In the present study, the effects of intra-cerebral hippocampus (CA1) injections of apomorphine D1, D2-like receptors agonists on morphine-induced place preference in male Wistar rats have been investigated. Subcutaneous administration of different dose of morphine sulphate (1, 3, 6 and 9 mg/kg) produced a dose-dependent conditioned place preference (CPP). Intra-cerebral hippocampus (CA1) admin...