Researchers at the BUSM now have evidence that the anti-obesity medication rimonabant might lead to symptoms of anxiety during withdrawal from palatable food and they have confirmed that this anxiety is likely stemming from a certain part of the middle of the brain known as the amygdala. Pietro Cottone, PhD, co-director of BUSM’s Laboratory of Addictive Disorders, and colleagues have demonstrated that the drug, which had been pulled from the market in 2008 due to concern for depression and other psychiatric symptoms, led to decreased food intake, weight loss, and increased anxious behavior in a research model. During periods of withdrawal they noted increases in certain chemicals and receptors where rimonabant works, which they feel might be a defense mechanism on the part of the body to lessen withdrawal symptoms and reduce anxiety. Rimonabant blocked this defense mechanism and this might be an explanation for why it had negative psychatric effects. This study currently appears in Neuropsychopharmacology.
“Given our finding of an adaptive mechanism in the brain which is blocked by rimonabant and knowing the benefits this drug has, we believe that medications which act similarly to rimonabant might be beneficial in treating obesity if they remain out of the brain” said senior author Cottone. “Our findings will be important to improve the pharmacological profile of the next generation of anti-obesity drugs,” added Angelo Blasio, PhD, post-doctoral fellow in the Laboratory of Addictive Disorders.
In addition to Cottone and Blasio, members of the Laboratory of Addictive Disorders participating in the cited study include Attilio Iemolo, PhD, and Valentina Sabino, PhD. Other researchers involved in the study were Dr. Eric Zorrilla from The Scripps Research Institute, Drs. Vincenzo Di Marzo, Stefania Petrosino, Pierangelo Orlando and Fabio Iannotti from the Endocannabinoid Research group, Dr. Luca Steardo from Sapienza University of Rome and Dr. Kenner Rice from NIH.
Funding for this work was provided by the National Institute on Drug Abuse, the National Institute of Mental Health, the National Institute on Alcohol Abuse and Alcoholism, the National Institute on Diabetes, Digestive and Kidney Disorders, the NIH Intramural Research Programs of the National Institute on Drug Abuse, the Peter Paul Career Development Professorship, and by Boston University’s Undergraduate Research Opportunities Program.