Reviews of Physiology, Biochemistry and Pharmacology, Vol. 173

Catechol-O-methyltransferase (COMT) is an enzyme that catalyses the methylation of catechol substrates, classically in catecholamine metabolism, but also acting upon other substrates such as oestrogen and polyphenols. Although its classical function has been established for more than five decades, an ever expanding COMT role in other pathways and diseases has become a subject of active study in recent years. The most highlighted domains are related with COMT involvement in neuropsychiatric disorders and its role in the neurobiology of cognition, behaviour, emotions, pain processing and perception, sleep regulation, addictive behaviour and neurodegeneration. Nonetheless, great attention is also being devoted to a possible COMT contribution to the development of cardiovascular disorders and hormonally influenced diseases, including cancer. This review aims to update the role of COMT function and its involvement in cardiovascular and neurological disorders. *Pedro Bastos and Tiago Gomes equally contributed to this work. P. Bastos Molecular Biology Center, Blood Bank and Transfusion Department, S. João Hospital, 4200319 Porto, Portugal T. Gomes Department of Neurology, S. João Hospital, 4200-319 Porto, Portugal Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal L. Ribeiro (*) Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal Department of Public Health and Forensic Sciences, and Medical Education, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal I3S – Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal e-mail: lribeiro@med.up.pt