-5-1镇痛药.ppt

第 19 章 镇痛药 Opioid analgesics Opioid receptors[阿片受体] The major effects of the opioid are mediated by 3 families of receptors:μ, κand δ. Each of which exhibits a different specificity for the drug(s) it binds. Opioid interact stereo-specifically[立体特异性] with protein receptors on the membranes of certain cells[膜受体] in the CNS ，on nerve terminals [神经末梢]in the periphery ，and on cells of the gastrointestinal tract[胃肠道细胞] Strong agonists[强效激动剂] Morphine[μ, κ, δ .] is the major analgesic drug contained in crude opium and is the prototype agonist. 吗啡是阿片主要的镇痛药物 Codeine[μ, κ, δ ,σ.] is present in lower concentrations and is inherently less potent. 可待因浓度低，作用弱。 Morphine [吗啡] 阿片类作用于受体后，阻断神经冲动的 传递而产生镇痛等各种效应。 Analgesia[镇痛]: relieve pain both by raising the pain threshold at the spinal cord level ,and more importantly, by altering the brain’s perception of brain. Patients treated with morphine are still aware of the presence of pain ,but the sensation is not unpleasure. [在脊髓水平升高疼痛阈，改变脑部疼痛感受。病人用药后，能感觉疼痛，却没有不快感] Euphoria[欣快感]:powerful sense of contentment and well-being. 欣快感：强大的满足感和幸福感 Depression of cough reflex[咳嗽反射]: not correlate closed with analgesic and respiratory depressant properties of opioid drugs. Respiratory depression[呼吸抑制] : reduction of the sensitivity of respiratory center neurons to carbon dioxide Emesis[催吐]: it directly stimulates the chemoreceptor trigger zone in the area postrema 直接刺激延脑催吐化学感受区的极后区 Miosis[缩瞳]：the pinpoint pupil, characteristic of morphine use (μ, κ) . This is important diagnostically because most other causes of coma and respiratory depression produce dilation of the pupil. 缩瞳：针尖样瞳孔，以 μ, κ受体介导，是重要的诊断措施。其他许多原因引起的昏迷、呼吸抑制引起瞳孔扩大 Actions 三镇-一抑-一催缩 Gastrointestinal tract [胃肠道]: it decreases motility of smooth muscle and increases tone[蠕动减弱，张力提高]，it increases pressure in the biliary tract[胆道压力]，increases the tone of the anal sphincter[肛门括约肌]，produces constipation[便秘].