Regional sympathectomy induced by intra-arterial 6-hydroxy-dopamine

Single intra-carotid injections of 5-15 mg of 6-OH-DA HBr in adult cats reduced or abolished the responses of the ipsilateral nictitating membrane to electrical stimulation of post-ganglionic sympathetic nerves and intra-carotid injections of tyramine; the responses of the contralateral nictitating membrane to the same stimuli remained normal. One to five days after 6-OH-DA, the ipsilateral nictitating membranes, unresponsive to sympathetic stimulation, were hypersensitive to i.v. injections of adrenaline or noradrenaline. The advantages of regional over systemic chemical sympathectomy are discussed.