(Georgia Institute of Technology, 2022-05)
Rhangos, Isabella
Methamphetamine (METH) increases sexual motivation in ovariectomized female rats via direct influence on the mesolimbic dopaminergic pathway. METH’s effects on dopaminergic activity are dependent on the coadministration of ovarian hormones. In order to determine the mechanism through which METH stimulates the dopaminergic pathway, an analysis was performed on autoradiograms collected from the key mesolimbic brain regions of female rats: the medial amygdala (MeA), ventromedial nucleus (VMN), and the nucleus accumbens (NAcc). The dopaminergic receptor binding densities of both D1- and D2-type receptors were measured and compared between the groups of rats who received METH, ovarian hormones, METH and ovarian hormones, or a control injection. This analysis concluded that METH and ovarian hormone administration do not significantly change the number of bound dopaminergic receptors in any of the analyzed brain regions. The analysis also determined that there is potential lateralization of the MeA, as well as D2-autoreceptor activity in the MeA. These findings are significant in that they indicate that METH and ovarian hormone administration are activating the dopaminergic pathway, but that the change is occurring at a mechanistic location other than the number of bound dopaminergic receptors.