Contingent Methamphetamine Administration Decreases Dopamine and Vesicular Monoamine‐2 Transporter Function

Abstract

Methamphetamine (METH) is a highly addictive drug with the potential for long‐term health consequences. Although it has been reported in rodent models that METH can have detrimental effects on striatal dopaminergic neurons using non‐contingent dosing regimens, relatively little research has evaluated the effects of METH on dopaminergic neurons using a contingent dosing regimen. Thus, the current study examined if METH self‐administration alters dopamine (DA) transporter (DAT) and vesicular monoamine transporter‐2 (VMAT‐2) function in a manner similar to that caused by non‐contingent administration. Following food training and jugular vein catheter implantation, male rats were given 4 h of access to either 0.06 mg/infusion of METH or saline using a FR1 schedule for 5 d. Rats were sacrificed 1 h after the final session. Results revealed both decreased DAT and VMAT‐2 function in METH compared to saline‐treated controls in striatal tissue. Overall, these results suggest that contingent METH treatment decreases monoaminergic transporter function. The relationship among pressing behavior, METH/amphetamine levels and transporter function will be discussed.Supported by: DA09407, 019447, 013367, 00869, 11389, 04222, 00378