1.可待因，吗啡和h.tyr.d-arg.gly.phe（4-NO2）pro.nh2（化合物BW443C）的抗毒性，抗伤害感受和呼吸抑制作用的作用。通过使用纳洛啡和N-甲基分类的抗性和抗伤害感受效应的拮抗作用。纳洛酮用于拮抗呼吸道抑郁症。2.抗柠檬酸蒸气诱导的咳嗽的抗呼吸ED50分别用于可待因，吗啡和BW443C，9.1（5.8-15），1.3（0.7-2.4）和1.2（0.7-2.4）和1.2（0.6-2.6）MGKG-1 S.C.和8.7（4.2-12），1.6（1.2-1.9）和0.67（0.002-3.3）mg kg-1，i.v.皮下可待因（25 mg kg-1）吗啡（8.1 mg kg-1）和BW443C（2.5 mg kg-1）的抗呼吸作用显着拮抗皮下纳拉氨基（3.0 mg kg-1）和N-甲基诺（3.0 mg kg-1）（3.0 mg kg-1）kg-1）。3.在多个脚趾pinch测试中，可待因和吗啡的抗迷人ED50（置信度限制为95％）分别为18（16-22）和2.3（0.4-4.3）mg kg-kg-1，s.c。。复合BW443C的剂量为2.5和10 mg kg-1 s.c.，这与其缺乏渗透到CNS相一致。 Subcutaneous nalorphine (3.0 mg kg-1) antagonized the antinociceptive action of codeine (25 mg kg-1) and morphine (8.1 mg kg-1). In contrast, N-methylnalorphine (3.0 mg kg-1) had no significant effect on the antinociceptive action of codeine and morphine, suggesting lack of penetration of the CNS by N-methylnalorphine. 4. At doses near to the i.v. ED50 values for the antitussive activity, morphine (1.5mg kg- ', i.v.) and codeine (10mg kg-', i.v.) caused small but significant depressions of ventilation (7.0 +/- 2.3% and 16.5 +/- 8.4% respectively). Higher doses of morphine (10, 30 and 60mg kg- ', i.v.) caused further doserelated depression of ventilation (9.6 +/- 5.3%, 22.4 +/- 6.2% and 36.2 +/- 9.6% respectively) whereas codeine (30 and 60mg kg-' i.v.) caused stimulation of ventilation which was marked (191.3 +/- 43.9%) at 60 mg kg-'. 5. Compound BW443C in doses of 1 or 10mgkg-',i.v. (approximately equal to, and 10 times the EDo for antitussive activity) did not cause significant depression of ventilation. Only at higher doses of 30 and 60mg kg-', i.v. was there a significant decrease in minute volume (13.1 +/- 6.8% and 15.9 +/- 1.89% respectively). The depression of ventilation caused by either BW443C (60mg kg-', i.v.) or morphine (60mg kg-', i.v.) was prevented by pretreatment with naloxone (3mg kg-', i.v.) administered 15 min before morphine or BW443C. 6. These results in the guinea-pig support the hypothesis that the antitussive action of the opiates codeine and morphine and the opioid pentapeptide BW443C do not require penetration of these drugs into the CNS.