Sensory transduction mechanisms in chronic pain

疼痛通常保护我们免受伤害，或者警告我们受伤，这样我们就能保护身体受伤的部位。在这些情况下，当有害刺激消失或伤口愈合时，疼痛就会停止。然而，对一些人来说，疼痛是持续的，不再与受伤有关，也没有有益的保护作用。这种慢性疼痛与某些癌症和炎症性疾病（如关节炎）有关，可在正常感觉疼痛的神经受到病毒感染或糖尿病相关的神经损伤后发生。据估计，世界上有3亿人患有慢性疼痛。目前的止痛药主要是基于阿司匹林或阿片类药物。阿司匹林类药物的缺点是会导致胃出血，对神经损伤疼痛无效。除了对成瘾的担忧外，鸦片类药物还会导致镇静、严重便秘，甚至可能使患者停止呼吸。用来治疗神经损伤疼痛的药物还有哪些？抗惊厥药？也有明显的不良副作用，如严重的头晕。因此，对新型止痛药的需求很大。

Pain normally protects us from damaging ourselves or warns us of an injury so that we protect the injured part of the body. In these cases, the pain ceases when the harmful stimulus has gone or the injury has healed. However, in some people the pain is persistent, is no longer associated with injury and has no beneficial protective effect. This chronic pain is associated with some cancers and inflammatory diseases such as arthritis, and can occur after viral infection of the nerves that normally sense pain or after nerve damage associated with diabetes. It is estimated that 300 million people in the world suffer from chronic pain. The current pain killing drugs are mostly based on aspirin or are opiates. The aspirin-like drugs have the drawbacks that they can cause stomach bleeding and are ineffective against nerve injury pain. Apart from concerns about addiction, the opiate like drugs cause sedation, severe constipation and may even stop the patient breathing. The only other types of drugs used to treat nerve injury pain ? anticonvulsant drugs ? also have pronounced undesirable side effects, such as severe dizziness. So there is a large need for new pain killing drugs.