Destruction of locus coeruleus neuronal perikarya after injection of anti-dopamine-B-hydroxylase immunotoxin into the olfactory bulb of the rat.

Saporin, a ribosome-inactivating protein, was coupled to a monoclonal antibody to dopamine-B-hydroxylase (DBH) and injected unilaterally into the olfactory bulb of rats. After 4-13 days survival, the rat brain was processed histologically and the locus coerulei (LC) examined with Nissl and anti-DBH staining. There were degenerating dendrites in surviving LC neurons on the side ipsilateral to the immunotoxin-injected olfactory bulb. The number of Nissl-positive LC neurons in a transverse section through the caudal one third of the LC was reduced from 116+/-10 to 50+/-8 neurons (P < 0.01, n = 7) and the number of DBH-positive neurons in the more rostral LC sections was reduced from 13+/-2 to 5+/-1 (P < 0.05, n = 4). Our results indicate that it is possible to lesion LC neurons via retrograde intraaxonal transport of saporin-anti-DBH immunotoxin from the olfactory bulb.