ABSTRACT
Effects of cimetidine [CIM] on locomotor is controversial. This study was designed to evaluate the effects of CIM on motor activity and possible roles of opioid receptors in CIM-induced decrement in locomotor activity in mice. Thirty-six male mice [25-30gr] were divided into six groups in this study. Locomotor activity was evaluated using an automated activity monitor system. CIM [50 mg/kg, i.p.] was injected 25 min before testing in presence or absence naloxone [2 mg/kg, sc]. Morphine [5 mg/kg, i.p] was injected 25 min before testing in the presence or absence CIM. Decreased motor activity significantly. Pretreatment of or morphine did not change CIM - induced response significantly. The results showed that CIM significantly decreased motor activity in mice [P=0.000]. Pretreatment of nalxone did not change CIM-induced response significantly. Morphine alone did not change motor activity. Pretreatment of CIM did not change morphine-induced response. Data indicated that cimetidine can reduce motor activity independence from interaction with opioid receptors