24 May 2015

Ma CL et al. Neurosci Bull 2015; 31: 227-234.

Novel and efficient animal models, especially in non-human primates, are required to accelerate development of new medications for ADHD, a recent Chinese review reports.

This review summarised the role of α2A-adrenoceptors in ADHD and how they can be represented in animal models. ADHD symptoms can be mimicked by blocking the α2A-adrenoceptors in the prefrontal cortex (PFC) of the brain. For example, infusion of α2A-adrenoceptor antagonists to induce blockade of the α2A-adrenoceptors in the spontaneously hypertensive rat (SHR) and non-human primate models has been shown to produce ADHD symptoms/phenotypes, including hyperactivity, impulsivity and poor attention/working memory. Conversely, administration of α2A-adrenoceptor agonists into the PFC of non-human primates has been shown to improve working memory, visual object discrimination and visuoassociative learning.

These findings support the feasibility of treating ADHD through stimulation of α2A-adrenoceptors in the PFC as one mechanism. However, researchers acknowledge that limitations with current animal models, particularly the SHR which does not fulfil all the behavioural and pharmacological profiles of an ADHD model, support the need for improved animal models. Future development of non-human primate models, which enable investigation of the role of prefrontal α2A-adrenoceptors in ADHD, would be of great benefit to researchers.