كليدواژه :
Morphine , فلوكستين , تحمل , بي دردي , مورفين , Fluoxetine , Tolernace , Analgesia
چكيده لاتين :
Several studies show that serotoninergic system is involved in tolerance to analgesic effects of opioids. According to some reports, increase of serotoninergic activity potentiates morphine analgesia, as well as decreases tolerance to analgesic effect. In this study, the effect of fluoxetine, as a serotonin reuptake inhibitor, on tolerance to analgesic effect of morphine was studied in male rats by using hot plate test (50±1 °C). To determine tolerance appearing time, pain response latency time was recorded daily in morphine (lmg/kg, i.p. daily) treated rats. Results show that tolerance to analgesic effect of morphine appears on day nine. Co-injection of morphine with fluoxetine (2, 4, 8 and 10 mg/kg, i.p.) increases analgesia and tolerance appearing time in a dose-dependent manner. Acute fluoxetine injection (10 mg/kg, i.p.) on ninth day, only increased analgesia until day eleven, and it has not any significant effect on tolerance appearing time. We suggest that fluoxetine increases morphine analgesia and tolerance appearing time probably through increasing serotonin activity. However, the exact role of serotoninergic system remains unclear and further investigation should be done.
