RATIONALE: The long-term neurochemical effects produced by the repeated administration of methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) are well documented; however, the functional consequences have not been clearly defined. OBJECTIVE: The present study was designed to investigate whether rats treated with a monoamine-depleting regimen of MA or MDMA exhibit disturbances in locomotor activity during the diurnal and nocturnal cycles. METHODS: Rats were treated with the vehicle or a monoamine-depleting regimen of MA or MDMA (10 mg/kg, IP, every 2 h for four injections on a single day). One week after drug treatment, the rats were placed in residential activity chambers and their locomotor activity was monitored for the next 7-day/night cycles. RESULTS: MA-treated rats exhibited depletions of striatal dopamine and serotonin content of approximately 70%, whereas MDMA-treated rats showed depletions of striatal serotonin content of approximately 50%. Rats treated with MA demonstrated a significant reduction in diurnal, but not nocturnal, locomotor activity, whereas MDMA-treated rats exhibited significant reductions in both diurnal and nocturnal locomotor activity. Analysis of the difference in activity between the nocturnal and diurnal cycles revealed that MA-treated animals exhibited a significantly greater change in activity as compared to that observed in vehicle- and MDMA-treated rats. CONCLUSIONS: Although it is unknown whether the adaptations in locomotor activity observed in MA- and MDMA-treated rats are due to the loss of dopamine and/or serotonin, these data suggest that the administration of a monoamine-depleting regimen of MA or MDMA results in alterations in light-cycle-dependent locomotor activity.
RATIONALE: The long-term neurochemical effects produced by the repeated administration of methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) are well documented; however, the functional consequences have not been clearly defined. OBJECTIVE: The present study was designed to investigate whether rats treated with a monoamine-depleting regimen of MA or MDMA exhibit disturbances in locomotor activity during the diurnal and nocturnal cycles. METHODS:Rats were treated with the vehicle or a monoamine-depleting regimen of MA or MDMA (10 mg/kg, IP, every 2 h for four injections on a single day). One week after drug treatment, the rats were placed in residential activity chambers and their locomotor activity was monitored for the next 7-day/night cycles. RESULTS: MA-treated rats exhibited depletions of striatal dopamine and serotonin content of approximately 70%, whereas MDMA-treated rats showed depletions of striatal serotonin content of approximately 50%. Rats treated with MA demonstrated a significant reduction in diurnal, but not nocturnal, locomotor activity, whereas MDMA-treated rats exhibited significant reductions in both diurnal and nocturnal locomotor activity. Analysis of the difference in activity between the nocturnal and diurnal cycles revealed that MA-treated animals exhibited a significantly greater change in activity as compared to that observed in vehicle- and MDMA-treated rats. CONCLUSIONS: Although it is unknown whether the adaptations in locomotor activity observed in MA- and MDMA-treated rats are due to the loss of dopamine and/or serotonin, these data suggest that the administration of a monoamine-depleting regimen of MA or MDMA results in alterations in light-cycle-dependent locomotor activity.
Authors: Rowan P Ogeil; David J Kennaway; Mark D Salkeld; Shantha M W Rajaratnam; Jillian H Broadbear Journal: Psychopharmacology (Berl) Date: 2011-10-26 Impact factor: 4.530
Authors: Charles V Vorhees; Elizabeth He; Matthew R Skelton; Devon L Graham; Tori L Schaefer; Curtis E Grace; Amanda A Braun; Robyn Amos-Kroohs; Michael T Williams Journal: Synapse Date: 2010-10-08 Impact factor: 2.562
Authors: Arnold Gutierrez; Samantha L Regan; Christopher S Hoover; Michael T Williams; Charles V Vorhees Journal: Psychopharmacology (Berl) Date: 2019-03-27 Impact factor: 4.530