Portal de Periódicos da CAPES

Fluoxetine attenuates morphine-induced locomotion and blocks morphine-sensitization

1997; Elsevier BV; Volume: 337; Issue: 2-3 Linguagem: Inglês

10.1016/s0014-2999(97)01308-3

1879-0712

Terrence Sills, Paul Fletcher,

Stress Responses and Cortisol

Repeated morphine treatments result in sensitization, an increase in the efficacy of morphine to stimulate locomotor activity. This study examined the effects of increasing serotonin (5-hydroxytryptamine, 5-HT) transmission on morphine-sensitization. For five days rats were administered saline or 5.0 mg/kg fluoxetine prior to treatment with saline or 5.0 mg/kg morphine. Twenty-one days later, rats were tested for their locomotor response to 2.0 mg/kg morphine. Fluoxetine treatment attenuated the locomotor activating effect of acute morphine treatments and blocked the sensitized response to the morphine challenge. These results indicate that increased 5-HT transmission attenuates the locomotor stimulating effects of morphine and prevents the development of morphine-sensitization.