Increased ethanol self-administration in developmentally low-level lead exposed rats: voluntary intake vs. operant conditioning

MARA S. MATTALLONI; LAURA DE GIOVANNI; LILIANA M. CANCELA; MIRIAM B. VIRGOLINI

Huerta Grande

Congreso; XXVII Congreso Anual de la Sociedad Argentina de Neurociencia; 2012

SAN

Several evidences demonstrate an interaction between lead (Pb) and drugs of abuse, particularly ethanol. This study aimed to investigate the influence of perinatal low-level Pb exposure on the motivational properties of ethanol by using a two-bottle ethanol/water test and an operant oral ethanol self-administration task. Thirty-five day-old male pups perinatally exposed to 220 ppm Pb were evaluated in their ethanol intake in a free-choice limited paradigm (2 h) at increasing ethanol concentrations (2-10%). Another group of animals was trained to associate the contingency of a lever press with 10% ethanol administration under a fixed-ratio 1 (FR 1) schedule of behavior, which was increased progressively across sessions to FR2, 5, 10, and 20. The results demonstrated that Pb-exposed rats voluntarily consumed more ethanol than their respective controls. Interestingly, the amount of ethanol ingested was sufficient to induce hyperlocomotion, as assessed immediately after the last ethanol (10%) intake session. We also demonstrated that Pb-exposed animals worked harder than the controls to obtain ethanol, evidencing a ?break point? at higher lever-press rates. These results are indicative of higher ethanol reinforcing properties in low-level Pb exposed rats as compared to controls.