Pain hypersensitivity in a pharmacological mouse model of attention-deficit/hyperactivity disorder

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 119; no. 30; p. e2114094119
• Main Authors: Bouchatta, Otmane, Aby, Franck, Sifeddine, Wahiba, Bouali-Benazzouz, Rabia, Brochoire, Louison, Manouze, Houria, Fossat, Pascal, Ba M'Hamed, Saadia, Bennis, Mohamed, Landry, Marc
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 26.07.2022
• Subjects: 6-Hydroxydopamine; Animal models; Animals; Attention Deficit Disorder with Hyperactivity - physiopathology; Attention deficit hyperactivity disorder; Biological Sciences; Circuits; Comorbidity; Cortex (cingulate); Disease Models, Animal; Dorsal horn; Electrophysiology; Genetics; Gyrus Cinguli - physiopathology; Hyperactivity; Hyperalgesia - chemically induced; Hyperalgesia - physiopathology; Hypersensitivity; Impulsive Behavior; Inflammation; Information processing; Mechanical stimuli; Mice; Neonates; Neural networks; Optics; Optogenetics; Oxidopamine - pharmacology; Pain; Pain - chemically induced; Pain - physiopathology; Pain perception; Phenotypes; Sympatholytics - pharmacology; attention-deficit/hyperactivity disorder; comorbidity; spinal cord; pain sensitization; anterior cingulate cortex
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2114094119

Clinical evidence suggests that pain hypersensitivity develops in patients with attention-deficit/hyperactivity disorder (ADHD). However, the mechanisms and neural circuits involved in these interactions remain unknown because of the paucity of studies in animal models. We previously validated a mouse model of ADHD obtained by neonatal 6-hydroxydopamine (6-OHDA) injection. Here, we have demonstrated that 6-OHDA mice exhibit a marked sensitization to thermal and mechanical stimuli, suggesting that phenotypes associated with ADHD include increased nociception. Moreover, sensitization to pathological inflammatory stimulus is amplified in 6-OHDA mice as compared to shams. In this ADHD model, spinal dorsal horn neuron hyperexcitability was observed. Furthermore, ADHD-related hyperactivity and anxiety, but not inattention and impulsivity, are worsened in persistent inflammatory conditions. By combining in vivo electrophysiology, optogenetics, and behavioral analyses, we demonstrated that anterior cingulate cortex (ACC) hyperactivity alters the ACC-posterior insula circuit and triggers changes in spinal networks that underlie nociceptive sensitization. Altogether, our results point to shared mechanisms underlying the comorbidity between ADHD and nociceptive sensitization. This interaction reinforces nociceptive sensitization and hyperactivity, suggesting that overlapping ACC circuits may be targeted to develop better treatments.