The Acute Effects of Methamphetamine and 1-Benzylpiperazine on Aggressive Behaviour in Adolescent Male Hooded Rats

Abstract

Violent crime and aggressive behaviour are of increasing concern in New Zealand. Much of this is displayed by adolescent males who have an association with some form of substance use, abuse or dependence. This is especially relevant for stimulant drugs, especially methamphetamine (MA), and 1-benzylpiperazine (BZP). Previous research has shown that BZP has similar neurochemical and behavioural effects to MA, and there is a large volume of research showing an association between chronic MA use and aggression. In contrast to this, there has been little research into the consequences of a single administration of MA, which is often portrayed by the media as having the same detrimental effects as chronic use. The present study was designed to determine whether or not acute MA would induce aggressive behaviour in adolescent male hooded rats. In addition, the study also examined whether BZP had a similar effect to MA. Sixty male hooded rats aged between 41 to 50 postnatal days (PND), were utilised and divided into five groups of 12 rats each: saline; 1mg/kg (low dose) or 2mg/kg (high dose) MA; 10mg/kg (low dose) or 20mg/kg (high dose) BZP. The rats were tested using the resident/intruder test of aggression, consisting of eight measures of aggressive behaviour. The results suggested that, rats treated with either a low or high dose of MA or BZP were significantly less aggressive than saline-treated rats. There appeared to be little to distinguish between the two drugs in their effects on the responses recorded. It was concluded that an acute administration of either MA or BZP did not increase aggression, and thus did not support the view that aggression will result from a single dose of MA (or indeed BZP that has not been previously investigated in this context).