Retrogradely transported CTB-saporin kills sympathetic preganglionic neurons

AIMING to ablate sympathetic preganglionic neurons (SPN) innervating a defi ned target, we injected saporin conjugated to cholera toxin B subunit (CTB) unilaterally into the superior cervical ganglion of rats. In spinal cord s egments T1-T3, the numbers of cholinergic neurons in the intermediolateral cell column ipsilateral and contralateral to the injected ganglion were sig nificantly different by 3 days post-injection. By day 14, 77% of ipsilatera l cholinergic neurons had disappeared. A higher percentage of neurons were killed in T1-T2 than in T3. Comparing SPN counts from CTB-saporin injected rats and counts from rats receiving unconjugated CTB into the superior cerv ical ganglion indicated that 84% of SPN supplying the ganglion had died by 14 days. Retrogradely transported CTB-saporin kills sympathetic preganglion ic neurons and may also eliminate other types of neurons that transport CTB . (C) 1999 Lippincott Williams & Wilkins.