Summary of the experimental design.

EtOH = ethanol (1.25 g/kg) administered 16 times in two daily intraperitoneal (i.p.) injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period over 14 days. Coca = cocaine given for three daily i.p. injections separated by a 60-min interval over a period of 12 subsequent days in ascending doses as follows: two days of 5 mg/kg, three days of 15 mg/kg, two-day period of abstinence, and five days of 25 mg/kg. Sal = saline (NaCl 0.9% w/v) given at the same treatment conditions as EtOH and coca depending on the group (control mice). OF = open field, EPM = elevated plus maze, PPI = prepulse inhibition, OR = object recognition, TST = tail suspension test. PND = Post-natal day. The experimental groups constituted were: Sal-Sal, Sal-Coca, EtOH-Sal, EtOH-Coca (in Study 1 and 3), Sal, and EtOH (in Study 2). For more details see the materials and methods section.