Sensitization to the Motor Stimulant Effects of 3,4-Methylenedioxypyrovalerone (MDPV) and Cross-Sensitization to Methamphetamine in Rats
Author(s): Lucas RWatterson, Peter R. Kufahl, Sara B Taylor, Natali E Nemirovsky, and M Foster Olive
Abstract
Background. In recent years, there has been a dramatic increase in abuse of the synthetic cathinone 3,4-methylenedioxypyrovalerone (MDPV), often in combination with other illicit stimulants. Purpose.We sought to determine if repeated exposure toMDPV would produce sensitization to the motor stimulant effects of the drug, and whether cross-sensitization would develop with the stimulant effects of methamphetamine (METH). Study design. Male Sprague-Dawley rats were administered MDPV (1 mg/kg or 5 mg/kg) or saline once daily for five days at 24 h intervals, or were administered MDPV (1 mg/kg) or saline once daily for five days at 48 h intervals. For crosssensitization experiments, rats were administered METH (1 mg/kg) or MDPV (1 mg/kg or 5 mg/kg) once daily for five days at 48 h intervals and, following a five-day incubation period, were given an acute challenge injection of eitherMDPV (0.5mg/kg) orMETH (0.5 mg/kg), respectively. Results. Rats repeatedly administered MDPV (1 mg/kg) every 48 h, but not every 24 h, demonstrated increased motor activity when given either a subsequent challenge of MDPV (0.5 mg/kg IP) or METH (0.5 mg/kg), indicating the development of behavioral sensitization and cross-sensitization, respectively. Moreover, rats repeatedly administered METH (1 mg/kg) every 48 h did not exhibit cross-sensitization to the motor stimulating effects of a subsequent challenge with MDPV (0.5 mg/kg). Conclusion. These results suggest that specific patterns of MDPV administration may lead to lasting changes in behavioral responses to subsequent METH exposure.
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