5-HT2 receptor agonists increase spontaneous sympathetic nerve discharge.

The selective 5-HT2 agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) produced a marked increase in spontaneous sympathetic nerve discharge recorded from the inferior cardiac nerve in chloralose anesthetized cats. DOI (0.01-1.0 mg/kg i.v.) increased sympathetic nerve discharge to a maximum of 1750% of control values. The increase in sympathetic nerve discharge produced by DOI was reversed by the 5-HT2 antagonists ketanserin and LY 53857. In addition, pretreatment with ketanserin, but not prazosin, completely prevented the increase in sympathetic nerve discharge produced by DOI. These data are discussed in relationship to the role of serotonin in the regulation of activity in central sympathetic pathways.