Neuronotrophic factors: effects on central cholinergic regeneration in vivo

To determine if neurotrophic factors (NTFs) which either support the survival (CNTF) or promote neuritic outgrowth (PNPF) of peripheral cholinergic neurons in vitro affect central cholinergic regeneration in vivo, NTFs were administered intracerebrally to rats after injury to septohippocampal fibers. Choline acetyltransferase activity within intrahippocampal iris implants was used as an index of cholinergic innervation. CNTF stimulated cholinergic sprouting while PNPF was ineffective under our experimental conditions, suggesting that the effects of other NTFs in vivo may be mediated by enhanced neuronal survival after injury rather than increased axonal sprouting.