This disclosure relates to new heterocyclic compounds that may be used to modulate a histamine receptor in an individual. Pyrido[3,4-b]indoles are described, as are pharmaceutical compositions comprising the compounds and methods of using the compounds in a variety of therapeutic applications, including the treatment of a cognitive disorder, psychotic disorder, neurotransmitter-mediated disorder and/or a neuronal disorder.本案係關於可用以調節個體之組織胺受體之新穎雜環化合物。本發明描述吡啶并[3,4-b]吲哚,亦描述包含該等化合物之醫藥組合物、及該等化合物在包括治療認知病症、精神病、神經傳遞素介導之病症及/或神經元病症之多種治療應用中的使用方法。