AnalgesicsZhang, Bin1 -a. Acute pain (sharp pain)b. Chronic pain (dull pain)2 -Pain transmission pathwayNoxious stimuliPGsK+、H+BK5-HTPrimary afferent fibresnociceptorSpinal cordLimbic systemSomato-sensory cortexmood effect, the affective aspect of painthe sensory aspect of painDorsal horn3 -severe pain Opioids (eg. Morphine) inflammatory pain NSAIDs (eg. Aspirin) local anaesthesia smooth muscle colic angina pectoris induced by coronary artery spasm trigeminal pain Drug treatment of paincholinoc