Social support, oxytocin and motivation for methamphetamine

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Summary/Abstract Addiction to methamphetamine (METH) is a major public health concern, however there are no effective treatments. Although METH is used by both men and women, women are younger when they start using METH, and show higher rates of dependence compare to men. Women also report a higher exposure to traumatic events and often start using to cope with psychological problems. Social support has a positive influence on stress-coping and might also have protective effects against addiction and help promote decreased motivation to take METH. Females show greater motivation for cocaine than male rats and social housing (pair housing) attenuates the motivation for cocaine in females but not males. Here we investigate whether oxytocin (OT) mediates the effects of social housing on motivation for METH. It is hypothesized that the effects of social housing are mediated by OT-dependent attenuation of dopamine (DA) release in the nucleus accumbens core (NAc) after drug taking is established and that these effects will be greater in females than in males. Previous research has established that social housing attenuates the METH-induced increase in DA in dialysate from the NAc, and chronic low dose OT attenuates the motivation for METH in females rats. Experiments will test the following hypotheses: 1) with social housing the more dominant animal will have lower DA release compared to the non-dominant pair and individually housed animals. 2) Chronic intranasal OT treatment will modulate the DA response to METH; and 3) sex differences and/or individual differences in DA release will predict the motivation for self-administration of METH. Social housing attenuates the METH-induced increase in DA in dialysate from the NAc of female rats and OT attenuates motivation for METH in female rats. Fast scan cyclic voltammetry will be used to investigate the effect of social housing and chronic intranasal OT on DA release in NAc to determine if there are sex differences and whether individual differences in METH-induced DA release predict motivation for METH during subsequent self-administration studies.