CNTF-Treated Astrocyte Conditioned Medium Enhances Large-Conductance Calcium-Activated Potassium Channel Activity in Rat Cortical Neurons.
Seizure activity is linked to astrocyte activation as well as dysfunctional cortical neuron excitability produced from changes in calcium-activated potassium (KCa) channel function. Ciliary neurotrophic factor-treated astrocyte conditioned medium (CNTF-ACM) can be used to investigate the peripheral effects of activated astrocytes upon cortical neurons. However, CNTF-ACM's effect upon KCa channel activity in cultured cortical neurons has not yet been investigated. Whole-cell patch clamp recordings were performed in rat cortical neurons to evaluate CNTF-ACM's effects upon charybdotoxin-sensitive large-conductance KCa (BK) channel currents and apamin-sensitive small-conductance KCa (SK) channel current. Biotinylation and RT-PCR were applied to assess CNTF-ACM's effects upon the protein and mRNA expression, respectively, of the SK channel subunits SK2 and SK3 and the BK channel subunits BKα1 and BKβ3. An anti-fibroblast growth factor-2 (FGF-2) monoclonal neutralizing antibody was used to assess the effects of the FGF-2 component of CNTF-ACM. CNTF-ACM significantly increased KCa channel current density, which was predominantly attributable to gains in BK channel activity (p < 0.05). CNTF-ACM produced a significant increase in BKα1 and BKβ3 expression (p < 0.05) but had no significant effect upon SK2 or SK3 expression (p > 0.05). Blocking FGF-2 produced significant reductions in KCa channel current density (p > 0.05) as well as BKα1 and BKβ3 expression in CNTF-ACM-treated neurons (p > 0.05). CNTF-ACM significantly enhances BK channel activity in rat cortical neurons and that FGF-2 is partially responsible for these effects. CNTF-induced astrocyte activation results in secretion of neuroactive factors which may affect neuronal excitability and resultant seizure activity in mammalian cortical neurons.
Department of Histology and Embryology, Bengbu Medical College, Bengbu, Anhui, China.
Meiqun
M
Sun
Department of Gynecological Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui, China.
Hongli
H
Liu
Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated First People's Hospital, Shanghai, China.
Huanbai
H
Xu
Department of Immunology, Bengbu Medical College, Bengbu, Anhui, China.
Hongtao
H
Wang
Department of Respiration, Anhui Clinical and Preclinical Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Bengbu Medical College, No. 287 Changhuai Road, Bengbu, Anhui, 233000, China. wangxiaojing8888@163.com.
Xiaojing
X
Wang
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D020934:Ciliary Neurotrophic Factor / Q000494:pharmacology*; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000819:agonists / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D020934:Ciliary Neurotrophic Factor; D017077:Culture Media, Conditioned; D051036:Large-Conductance Calcium-Activated Potassium Channels
Calcium-activated potassium channel; Ciliary neurotrophic factor, CNTF