Background:: Caffeine consumption by children and adolescents has risen dramatically in recent years, yet the lasting effects of caffeine consumption during adolescence remain poorly understood.
Aim:: These experiments explore the effects of adolescent caffeine consumption on cocaine self-administration and seeking using a rodent model.
Methods:: Sprague-Dawley rats consumed caffeine for 28 days during the adolescent period. Following the caffeine consumption period, the caffeine solution was replaced with water for the remainder of the experiment. Age-matched control rats received water for the duration of the study. Behavioral testing in a cocaine self-administration procedure occurred during adulthood (postnatal days 62-82) to evaluate how adolescent caffeine exposure influenced the reinforcing properties of cocaine. Cocaine seeking was also tested during extinction training and reinstatement tests following cocaine self-administration.
Results:: Adolescent caffeine consumption increased the acquisition of cocaine self-administration and increased performance on different schedules of reinforcement. Consumption of caffeine in adult rats did not produce similar enhancements in cocaine self-administration. Adolescent caffeine consumption also produced an upward shift in the U-shaped dose response curve on cocaine self-administration maintained on a within-session dose-response procedure. Adolescent caffeine consumption had no effect on cocaine seeking during extinction training or reinstatement of cocaine seeking by cues or cocaine.
Conclusions:: These findings suggest that caffeine consumption during adolescence may enhance the reinforcing properties of cocaine, leading to enhanced acquisition that may contribute to increased addiction vulnerability.
Keywords: Development; adenosine; psychostimulant; reinforcement; substance use; vulnerability.