The effects of diltiazem, nifedipine and verapamil and the calcium channel agonist Bay K 8644 on the analgesic responses to the subcutaneous (s.c.) or intracerebroventricular (i.c.v.) administration of pentazocine and U 50488H were investigated in mice. 2. The three calcium channel antagonists and Bay K 8644 reduced the number of writhes induced by the intraperitoneal administration of acetic acid. 3. The analgesic responses to the low doses of pentazocine (s.c.) were additive with the effects of diltiazem, nifedipine or Bay K 8644; while, in contrast, the higher doses produced underadditive responses. Only verapamil increased the effects of the i.c.v. administration of the opioid. 4. The effects of U 50488H (s.c.) were additive with those of diltiazem and Bay K 8644; verapamil only increased the response to the lower dose of the opioid. Nifedipine plus pentazocine always induced underadditive responses. The i.c.v. effects of U 50488H were only increased by verapamil. 5. These findings are discussed in relation with a possible interaction of kappa agonists with calcium channels in the central nervous system.
摘要
研究了地尔硫䓬、硝苯地平、维拉帕米以及钙通道激动剂Bay K 8644对小鼠皮下（s.c.）或脑室内（i.c.v.）注射喷他佐辛和U 50488H后镇痛反应的影响。2. 三种钙通道拮抗剂和Bay K 8644减少了腹腔注射醋酸所致的扭体次数。3. 低剂量喷他佐辛（s.c.）的镇痛反应与地尔硫䓬、硝苯地平或Bay K 8644的作用呈相加效应；而相比之下，高剂量则产生低于相加的反应。只有维拉帕米增强了脑室内注射阿片类药物的作用。4. U 50488H（s.c.）的作用与地尔硫䓬和Bay K 8644的作用呈相加效应；维拉帕米仅增强了对较低剂量阿片类药物的反应。硝苯地平加喷他佐辛总是产生低于相加的反应。U 50488H的脑室内作用仅被维拉帕米增强。5. 结合κ激动剂与中枢神经系统钙通道可能的相互作用对这些发现进行了讨论。
