ABSTRACT
Identifying a novel receptor was considered a major achievement in the before cloning years of pharmacology, and the histamine H3 receptor was among the very last ones to be identified through traditional pharmacological approaches. The role of brain histamine in convulsive disorders has been evoked for a long time, mainly starting from the observations of seizures as a side effect of H1 antihistamines crossing the blood—brain barrier. Autoreceptors, that is, receptors expressed on neuronal cell bodies or terminals and inhibiting catecholamine release or synthesis, had become, at the beginning of the 1980s, a field of intense research. In agreement, a single compound, proxyfan, was shown to act on the H3 receptor as a partial agonist, a full agonist, a neutral antagonist, a partial or full inverse agonist, depending on the test system on which it is evaluated.
