Evidence that central 5-HT 2A and 5-HT 2B/C receptors regulate 5-HT cell firing in the dorsal raphe nucleus of the anaesthetised rat (original) (raw)

1 Systemic administration of phenethylamine-derived, 5-hydroxytryptamine 2 (5-HT 2 ) receptor agonists inhibits the firing of midbrain 5-HT neurones, but the 5-HT receptors involved are poorly defined, and the contribution of peripheral mechanisms is uncertain. This study addresses these issues using extracellular recordings of 5-HT neurones in the dorsal raphe nucleus of anaesthetised rats. 2 The 5-HT 2 receptor agonists DOI ((7)-2,5-dimethoxy-4-iodoamphetamine hydrochloride) and DOB ((7)-2,5-dimethoxy-4-bromoamphetamine hydrobromide), caused a dose-related (10 -100 mg kg À1 i.v.) inhibition of 5-HT neuronal activity, with the highest dose reducing firing rates by 480%.