Studies on the site of action of clonidine utilizing a sympathetic-cholinergic system

Clonidine (30 mug/kg, i.v.) reduced centrally evoked electrodermal responses (EDR) following stimulation of reactive loci in the hypothalamus and medulla. The responses were most depressed following low frequency stimulation. Similar results were observed on the EDR evoked by stimulation of the cervical cord in the spinal cat. Little effect was seen following peripheral nerve stimulation. These results demonstrate that clonidine depresses the reactivity of this sympathetic-cholinergic system at all central levels including the cervical cord.