摘要
Because nerve growth factor(NGF)is elevated during inflammation,plays a causal role in the initiation of
Because nerve growth factor （NGF） is elevated during inflammation, plays a causal role in the initiation of hyperalgesia, and is known to activate the sphingomyelin signalling pathway, we examined whether NGF and its putative second messenger, ceramide, could modulate the excitability of capsaicin-sensitive adult sensory neurons. Using the whole-cell patch-clamp recording technique, exposure of isolated sensory neurons to either 100 ng/mL NGF or I mmol/L N-acetyl sphingosine （C2-ceramide） produced a 3-4 fold increase in the number of action potentials （APs） evoked by a ramp of depolarizing current in a time-dependent manner. Intracellular perfusion with bacterial sphingomyelinase （SMase） also increased the number of APs suggesting that the release of native ceramide enhanced neuronal excitability. Glutathione, an inhibitor of neutral SMase, completely blocked the NGF-induced augmentation of AP firing, whereas dithiothreitol, an in- hibitor of acidic SMase, was without effect. In the presence of glutathione and NGF, exogenous ceramide still enhanced the number of evoked APs, indicating that the sensitizing action of ceramide was downstream of NGF. To investigate the mechanisms of actions for NGF and ceramide, isolated membrane currents were examined.
出处
《生理学报》
CAS
CSCD
北大核心
2008年第5期603-604,共2页
Acta Physiologica Sinica
