Ciliary Neurotrophic Factor-treated Astrocyte Conditioned Medium Regulates the L-type Calcium Channel Activity in Rat Cortical Neurons

Astrocytes are activated by ciliary neurotrophic factor (CNTF) in vivo and in vitro, however, the consequences on the L-type calcium channel (LCC) of neurons are still poorly understood. Therefore, in the present study, whole-cell patch clamp, western-blot and RT-PCR assay were performed to evaluate the effects of CNTF-treated astrocyte conditioned medium (CNTF-ACM) on LCC current (ICa-L) and the expression of Cav1.2 and Cav1.3 in Sprague–Dawley rat cortical neurons. The results revealed that CNTF-ACM enhanced the amplitude of Ica-L and the expression of Cav1.3 significantly, but had no effects on Cav1.2 expression. We also found an increase in the concentration of fibroblast growth factor-2 (FGF-2) in CNTF-ACM by ELISA assay. Taken together, these findings indicate that CNTF induces the release of factors, including FGF-2, from astrocytes, thereby potentiating the activity of LCC in cortical neurons.