The Effects of Methamphetamine on Aggression

Abstract

Methamphetamine (METH) is a stimulant implicated in an increase of aggression in humans who abuse the drug. We hypothesize that METH exposure increases DA release into the TI pathway. Since DA inhibits the release of prolactin, which influences steroidogenesis and spermatogenesis, we hypothesized that the METH-induced increases in testosterone could promote aggressive behaviors associated with METH abuse. To test this hypothesis, a multi-construct resident-intruder aggression paradigm was used. In the current model, each male was paired with a female for the duration of the study (40-50 days) and required a successful pregnancy. Adult male mice (n=16) were administered a daily intraperitoneal injection of 5mg/kg METH or an equal volume of saline over the course of 10 days. The introduction of the intruder occurred on the 10th day, five hours after the final injection and 29 hours after the final injection (day 11). The testing consisted of two 10-minute intruder-resident sessions. Standard protocols were used to code for the following aggressive behaviors: the latency to first attack, the number of attacks, and the duration of persistent exploratory investigation (i.e., anogenital sniffing). There was no significance difference found for all three behaviors between the METH and saline group. Faculty Advisers: Steven Lloyd and Ryan Shanks