Fluoxetine attenuates morphine-induced locomotion and blocks morphine-sensitization.
Repeated morphine treatments result in sensitization, an increase in the efficacy of morphine to stimulate locomotor activity. 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.
Sills
T L
TL
Biopsychology Section, Clarke Institute of Psychiatry, Toronto, Ontario, Canada. terrence@psych.toronto.edu
Fletcher
P J
PJ
D000704:Analysis of Variance; D000818:Animals; D003864:Depression, Chemical; D005473:Fluoxetine / Q000494:pharmacology*; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000502:physiology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*
D005473:Fluoxetine; D009020:Morphine; D011985:Receptors, Serotonin; D017367:Selective Serotonin Reuptake Inhibitors