Ciliary neurotrophic factor enhances nicotinic synaptic transmission in sympathetic neurons

Nicotinic acetylcholine receptors mediate fast synaptic transmission in both central and peripheral nervous systems. These receptors play important roles in various physiological functions and are involved in different neurological diseases. A disruption in nicotinic receptor-mediated synaptic transmission due to the loss of nAChRs was detected in the brains of patients with Parkinson's disease and Alzheimer's disease. Although ciliary neurotrophic factor (CNTF) has been reported to promote the cholinergic properties by increasing the production and storage of acetylcholine, it is still unclear whether CNTF can enhance nicotinic synaptic neurotransmission. In this study, we found that CNTF dramatically enhanced the frequency and amplitude of nicotinic excitatory post-synaptic currents in rat superior cervical ganglion neurons maintained in a medium supplemented with nerve growth factor. Moreover, the number of neurons displaying nicotinic synaptic currents was also significantly increased by CNTF. These results suggest that CNTF could enhance nicotinic synaptic transmission via both presynaptic and postsynaptic mechanisms. The findings of this study reinforce the rationale for the usage of combinations of different neurotrophic factors for the therapy of neurodegenerative diseases.