This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Introduction to Central Nervous System, Subject name: Physiology
[{'content': 'In a demyelinating disease (e.g. multiple sclerosis), symptoms worsen with hot bath and improve with decreased temperature because: \nSelect and explain. \nA. Lower temperatures slow the gating kinetics of Na+ channels, B. AP duration increases with increased temperature, C. Activity of K+ channels is increased at lower temperatures, D. Inadequate recharging of the denuded axon at higher temperatures', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In demyelinating diseases after myelin is degraded, there is redistribution of Na+ channels along the nerve (normally present at nodes of Ranvier). Lower temperature alters the Na+ channel kinetics in a way to delay the closure, thus extra Na+ can come into the cell, which enable electronic conduction upto the point on the nerve where the next Na+ channel is. At higher temperature: there is increased leakage of charges from the cell membrane k/o increased capacitance of the nerve.', 'role': 'assistant'}]