Escalation of methamphetamine self-administration in adolescent and adult rats

• Published in: Drug and alcohol dependence Vol. 124; no. 1; pp. 149 - 153
• Main Authors: Anker, Justin J, Baron, Thomas R, Zlebnik, Natalie E, Carroll, Marilyn E
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01-07-2012; Elsevier
• Subjects: Addictive behaviors; Adolescence; Adolescents; Adult and adolescent clinical studies; Age Factors; Animals; Behavior, Addictive; Behavior, Animal - drug effects; Bingeing; Biological and medical sciences; Central Nervous System Stimulants - administration & dosage; Conditioning, Operant - drug effects; Dose-Response Relationship, Drug; Drug addiction; Eating - drug effects; Eating behavior disorders; Escalation; Impulsivity; Male; Medical sciences; METH; Methamphetamine; Methamphetamine - administration & dosage; Miscellaneous; Neuropharmacology; Pharmacology. Drug treatments; Psychiatry; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease); Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychopharmacology; Rat; Rats; Rats, Wistar; Self Administration; Substance abuse; METH; Adolescence; Rat; Bingeing; Escalation; Human; Amphetamine derivatives; Drug addiction; CNS stimulant; Illicit drug; Psychotropic; Rodentia; Metamfetamine; Sympathomimetic; Self administration; Eating disorder; Young animal; Vertebrata; Mammalia; Binge eating; Addiction; Adolescent; Adult animal
• ISSN: 0376-8716; 1879-0046
• DOI: 10.1016/j.drugalcdep.2012.01.004

Abstract Background Methamphetamine (METH) use has increased substantially in the last 10 years and poses a serious health concern, especially for young populations. Drug abuse primarily begins during adolescence, when uninhibited and excessive and drug intake is a common occurrence; thus, understanding the developmental patterns of addiction during this critical period is an essential step in its prevention. In the present study, the effect of age on the vulnerability to METH abuse was examined using a rat model of bingeing (i.e., escalation). Methods Adolescent and adult rats were compared during short (ShA, 2-h) and long-access (LgA, 6-h) to METH self-administration. On postnatal (PN) days 23 (adolescents) and 90 (adults), rats were implanted with i.v. catheters and trained to lever press for infusions of METH (0.05 mg/kg) during 2-h sessions. Once the rats reached a steady rate of METH self-administration, they were divided into ShA or LgA groups and allowed to self-administer METH for 15 additional days. Results Results indicated that adolescent rats earned significantly more infusions than adults under the LgA condition, but the age groups did not differ during ShA. Adolescents, but not adults, also significantly increased (i.e., escalated) METH self-administration across the 15 days of testing under the LgA condition. Further analysis indicated excessive responding during infusions in the LgA METH-exposed adolescents compared to the other groups, suggesting elevated impulsivity or motivation for drug. Conclusion These results demonstrate that adolescents are more vulnerable to the escalation of METH than adults during LgA.