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.
Novel fused tetracyclic heterocyclic compounds having a potent and highly selective effect of inhibiting cyclic GMP phosphodiesterase (cGMP-PDE) and a high safety; a process for producing the same; drugs characterized by containing at least one of these compounds as the active ingredient, in particular, preventives and/or remedies for pulmonary hypertension, ischemic heart diseases, erectile insufficiency, female sexual dysfunction or diseases against which cGMP-PDE inhibitory effects are efficacious and intermediates useful in producing the above compounds.