Caggiula A R, Epstein L H, Perkins K A, Saylor S
Department of Psychology, University of Pittsburgh, PA 15260, USA.
Psychopharmacology (Berl). 1995 Dec;122(3):301-6. doi: 10.1007/BF02246552.
Two methods were used to assess nicotine-induced antinociception: tail withdrawal from a hot water bath and hind paw withdrawal from a hotplate. Nicotine doses which produced 75-80% maximum response were 0.75 mg/kg (free base) for tail withdrawal and 0.35 mg/kg for paw withdrawal. The peripheral blocker chlorisondamine (0.1 mg/kg, SC) and the central antagonist, mecamylamine (1 mg/kg, SC) were each effective in blocking nicotine-induced increases in tail withdrawal latencies, suggesting that this effect of nicotine depends on either the action of nicotine at peripheral receptors or the functional integrity of those receptors. In contrast, nicotine-induced increases in paw withdrawal latencies were blocked by mecamylamine but not by chlorisondamine, even at other agonist/antagonist dose combinations. The results indicate that these two effects of nicotine involve at least partially separate pathways and may reflect a different mix of the antinociceptive and motor depressing effects of nicotine.
从热水浴中抽回尾巴以及从热板上抽回后爪。产生最大反应75 - 80%的尼古丁剂量，尾巴抽回为0.75毫克/千克（游离碱），爪子抽回为0.35毫克/千克。外周阻断剂氯异吲哚铵（0.1毫克/千克，皮下注射）和中枢拮抗剂美加明（1毫克/千克，皮下注射）均能有效阻断尼古丁诱导的尾巴抽回潜伏期增加，这表明尼古丁的这种作用要么取决于尼古丁在外周受体上的作用，要么取决于这些受体的功能完整性。相比之下，即使在其他激动剂/拮抗剂剂量组合下，尼古丁诱导的爪子抽回潜伏期增加也被美加明阻断，但未被氯异吲哚铵阻断。结果表明，尼古丁的这两种作用至少部分涉及不同的途径，可能反映了尼古丁镇痛和运动抑制作用的不同组合。
