Amphetamine, but not methylphenidate, increases ethanol intake in adolescent male, but not in female, rats.

Paul Ruiz,Ricardo Marcos Pautassi,Patricia Genovese,Cecilia Scorza,Aldo Calliari

doi:10.1002/brb3.939

Abstract

IntroductionThere has been an increasing interest in analyzing the interactions between stimulants and ethanol during childhood and adolescence. Stimulants are used to treat attention‐deficit hyperactivity disorder (ADHD) in these developmental stages, during which ethanol initiation and escalation often occur.MethodsThis study assessed the effects of repeated d‐amphetamine (AMPH) or methylphenidate (MPH) treatment during adolescence [male and female Wistar rats, between postnatal day (PD) 28 to PD34, approximately] on the initiation of ethanol intake during a later section of adolescence (PD35 to PD40).ResultsAmphetamine and MPH exerted reliable acute motor stimulant effects, but there was no indication of sensitized motor or anxiety responses. MPH did not affect dopamine (DA) levels, whereas AMPH significantly reduced insular levels of DA in both sexes and norepinephrine levels in females only. Repeated treatment with AMPH, but not with MPH, enhanced ethanol intake during late adolescence in male, but not in female, rats.ConclusionA short treatment with AMPH during adolescence significantly altered DA levels in the insula, both in male and females, and significantly enhanced ethanol intake in males. The present results suggest that, in adolescent males, a very brief history of AMPH exposure can facilitate the initiation of ethanol intake.

Highlights

There has been an increasing interest in analyzing the interactions between stimulants and ethanol during childhood and adolescence
The main new finding of the present study is that treatment with AMPH, but not with MPH, enhanced ethanol intake during late adolescence, in male Wistar rats
The males that had been exposed to AMPH had a mean average ethanol intake slightly below 5.5 g kg−1 24 hr−1, whereas control males drank around 3.0 g kg−1 24 hr−1

Summary

Introduction

There has been an increasing interest in analyzing the interactions between stimulants and ethanol during childhood and adolescence. Late infancy (Pilatti, Godoy, Brussino, & Pautassi, 2013) and adolescence (Pilatti, Read, & Pautassi, 2017) are developmental stages in which ethanol initiation normatively occurs and in which treatments that alter developmental trajectories of dopamine (DA) or other transmitter systems are likely to facilitate the escalation toward. AMPH and MPH exert their action by increasing the synaptic levels of catecholamine transmitters, such as DA, either by increasing their release from or by inhibiting their reuptake into neurons

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