Effects of metabotropic 2/3-glutamate receptor activation and inactivation on activity-based anorexia model in mice

Anorexia nervosa is an eating disorder disproportionately found in female human teens and young adults. It is often resistant to treatment, has a significant chance of relapse and is more lethal than other eating disorders, such as bulimia nervosa or Avoidant/Restrictive Food Intake Disorder (ARFID). There is no specific medication for the treatment of anorexia nervosa . Treatment consists of psychosocial means, psychotherapy, psychoeducation, and nutritional counseling. Medication is usually used for treating comorbidities such as anxiety or to decrease obsessive-compulsive tendencies. These medications cannot help the patient regain weight or treat core symptoms. Metabotropic 2/3-glutamate (mGluR2/3) receptor agonist (LY379268) and antagonist (LY341495) are promising pharmacological agents to treat psychiatric disorders. Both agonists and antagonists have been reported to have anxiolytic effects in different animal models of anxiety, while antagonists have shown antidepressant-like effects in preclinical studies. The activity-based anorexia (ABA) paradigm is used to model anorexia nervosa . It consists of giving mice access to a running wheel and restricting their feeding time. This causes mice to exercise more than mice without feeding time restriction and to eat less than mice without access to a moving running wheel. In this study, we subcutaneously injected female ABA model mice with a metabotropic 2/3-glutamate receptor agonist (LY379268) and antagonist (LY341495) in two experiments. Both compounds exacerbated weight loss by decreasing food intake as well as increasing physical activity. It can be concluded that the manipulation of mGluR2/3 receptors is detrimental for the ABA model and likely for anorexia nervosa as well. Highlights mGluR2/3 agonist LY379268 decreases food intake and body weight of the ABA model mGluR2/3 antagonist LY341495 decreases food intake and body weight of the ABA model Both agonist and antagonist produce the effect within 48 hours Both the agonist and antagonist are detrimental to the ABA-model