Adolescent but not adult ethanol binge drinking modulates cocaine withdrawal symptoms in mice

Abstract

Background: Ethanol (EtOH) binge drinking is an increasingly common behavior among teenagers that induces long-lasting neurobehavioral alterations in adulthood. An early history of EtOH abuse during adolescence is highly correlated with cocaine addiction in adulthood. Abstinence of cocaine abuse can cause psychiatric symptoms, such as anxiety, psychosis, depression, and cognitive impairments. This study assessed the consequences of adolescent exposure to EtOH on the behavioral alterations promoted by cocaine withdrawal in adulthood.

Methods: We pretreated juvenile (34-47 days old) or adult (68-81 days old) mice with EtOH (1.25 g/kg) following a binge-drinking pattern. Then, after a three-week period without drug delivery, they were subjected to a chronic cocaine treatment in adulthood and tested under cocaine withdrawal by the ensuing paradigms: open field, elevated plus maze, prepulse inhibition, tail suspension test, and object recognition. Another set of mice were treated with the same EtOH binge-drinking procedure during adolescence and were tested immediately afterwards under the same behavioral paradigms.

Results: Adolescent EtOH pretreatment undermined the anxiogenic effects observed after cocaine abstinence, reduced prepulse inhibition, and increased immobility scores in the tail suspension test following cocaine withdrawal. Moreover, the memory deficits evoked by these substances when given separately were enhanced in cocaine-withdrawn mice exposed to EtOH during adolescence. EtOH binge drinking during adolescence also induced anxiety, depressive symptoms, and memory impairments when measured immediately afterwards. In contrast, neither EtOH nor cocaine alone or in combination altered any of these behaviors when given in adulthood.

Conclusions: EtOH binge drinking induces short- and long-term behavioral alterations and modulates cocaine withdrawal symptoms when given in adolescent mice.

Fig 1

a, b and, c. Effects of the different drug treatment conditions on locomotion. Long-term effects of adolescent EtOH binge drinking after cocaine withdrawal in adulthood on locomotor activiy (PND 80, panel a); short-term effects of adolescent EtOH binge drinking on locomotor activity (PND 48, panel b); long-term effects of previous EtOH binge drinking after later cocaine withdrawal in adulthood on locomotor activity (PND 114, panel c). Bars depict mean ± SEM of the horizontal locomotion travelled in 10 min.

Fig 2

a and b. Long-term effects of adolescent EtOH binge drinking after cocaine withdrawal in adulthood on prepulse inhibition (PND 81–82). During adolescence mice (n = 10 per group) were pretreated for 14 days (PND 34–47) with Sal or EtOH (1.25 g/kg administered 16 times in two daily i.p. injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period), and in adulthood with Sal or Coca by three daily i.p. injections separated by a 60-min interval according to the following regime: 5 mg/kg on PND 68 and 69, 15 mg/kg from PND 70 to 72, a 2-day abstinence period, and 25 mg/kg from PND 75 to 79. Animals were tested on PND 82. Bars depict mean ± SEM of percentage of the PPI response for trials with prepulses of 75 dB (panel a) and 85 dB (panel b) for all groups (** and * p<0.01 and 0.05 respectively, significantly different from the rest).

Fig 3. Long-term effects of adolescent EtOH binge drinking after cocaine withdrawal in adulthood on tail suspension (PND 84).

During adolescence mice (n = 10 per group) were pretreated for 14 days (PND 34–47) with Sal or EtOH (1.25 g/kg administered 16 times in two daily i.p. injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period), and in adulthood with Sal or Coca by three daily i.p. injections separated by a 60-min interval according to the following regime: 5 mg/kg on PND 68 and 69, 15 mg/kg from PND 70 to 72, a 2-day abstinence period, and 25 mg/kg from PND 75 to 79. Animals were tested on PND 84. Bars depict mean ± SEM of the time (seconds) during which the mice remained immobile in the tail suspension test (* p<0.05 significantly different from the rest).

Fig 4. Long-term effects of adolescent EtOH binge drinking after cocaine withdrawal in adulthood on object recognition (PND 83–84).

During adolescence mice (n = 10 per group) were pretreated for 14 days (PND 34–47) with Sal or EtOH (1.25 g/kg administered 16 times in two daily i.p. injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period), and on adulthood with Sal or Coca by three daily i.p. injections separated by a 60-min interval according to the following regime: 5 mg/kg on PND 68 and 69, 15 mg/kg from PND 70 to 72, a 2-day abstinence period, and 25 mg/kg from PND 75 to 79. Animals were tested on PND 84. Bars depict mean ± SEM of the DI for all groups (** p<0.01 significantly different from the Sal-Sal group; ## p<0.01 significantly different from the rest).

Fig 5

a and b. Short-term effects of adolescent EtOH binge drinking on prepulse inhibition (PND 49–50). During adolescence mice (n = 10 per group) were pretreated for 14 days (PND 34–47) with Sal or EtOH (1.25 g/kg administered 16 times in two daily i.p. injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period). Animals were tested on PND 50. Bars depict mean ± SEM of percentage of the PPI response for trials with prepulses of 75 dB (panel a) and 85 dB (panel b) for all groups.

Fig 6

a and b. Short-term effects of adolescent EtOH binge drinking on tail suspension (PND 52, panel a) and object recognition (PND 51–52, panel b). During adolescence mice (n = 10 per group) were pretreated for 14 days (PND 34–47) with Sal or EtOH (1.25 g/kg administered 16 times in two daily i.p. injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period). Animals were tested on PND 52. Bars depict mean ± SEM of the time (seconds) during which the mice remained immobile in the tail suspension test (Fig 4A); and the DI for object recognition (Fig 4B) (* and ** p<0.05 and 0.01 respectively, significantly different from the Sal group).

Fig 7

a and b. Long-term effects of previous EtOH binge drinking after later cocaine withdrawal in adulthood on prepulse inhibition (PND 115–116). Over PND 68–81 mice (n = 10 per group) were pretreated with Sal or EtOH (1.25 g/kg administered 16 times in two daily i.p. injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period). Twenty-one days later, animals were treated with Sal or Coca in three daily i.p. injections separated by a 60-min interval according to the following regime: 5 mg/kg on PND 102 and 103, 15 mg/kg from PND 104 to 106, a 2-day abstinence period, and 25 mg/kg from PND 109 to 113. Animals were tested on PND 116. Bars depict mean ± SEM of percentage of the PPI response for trials with prepulses of 75 dB (panel a) and 85 dB (panel b) for all groups.

Fig 8. Long-term effects of previous EtOH binge drinking after later cocaine withdrawal in adulthood on tail suspension test (PND 118).

Over PND 68–81 mice (n = 10 per group) were pretreated with Sal or EtOH (1.25 g/kg administered 16 times in two daily i.p. injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period). Twenty-one days later, animals were treated with Sal or Coca in three daily i.p. injections separated by a 60-min interval according to the following regime: 5 mg/kg on PND 102 and 103, 15 mg/kg from PND 104 to 106, a 2-day abstinence period, and 25 mg/kg from PND 109 to 113. Animals were tested on PND 118. Bars depict mean ± SEM of the time (seconds) during which the mice remained immobile.

Fig 9. Long-term effects of previous EtOH binge drinking after later cocaine withdrawal in adulthood on object recognition (PND 118).

Over PND 68–81 mice (n = 10 per group) were pretreated with Sal or EtOH (1.25 g/kg administered 16 times in two daily i.p. injections separated by a 4-h interval on two consecutive days followed by a 48-h “drug-free” period). Twenty-one days later, animals were treated with Sal or Coca in three daily i.p. injections separated by a 60-min interval according to the following regime: 5 mg/kg on PND 102 and 103, 15 mg/kg from PND 104 to 106, a 2-day abstinence period, and 25 mg/kg from PND 109 to 113. Animals were tested on PND 118. Bars depict mean ± SEM of the DI for all groups (** p<0.01 significantly different from the Sal-Sal group).