Kaufman W R, Wong D L
Eur J Pharmacol. 1983 Jan 28;87(1):43-52. doi: 10.1016/0014-2999(83)90048-1.
Using isolated salivary glands of the ixodid tick Amblyomma hebraeum Koch, we tested the effectiveness of butaclamol and sulpiride in blocking fluid secretion stimulated by a number of agonists. (+)-Butaclamol was a potent inhibitor of dopamine, N-methyldopamine and noradrenaline (Ki congruent to 30-60 nM), but was less effective on ergometrine (Ki congruent to 310 nM). Tranylcypromine-stimulated fluid secretion in the absence and presence of (+)-butaclamol and (+/-)-sulpiride suggested that tranylcypromine's action is mediated through two receptors. (+/-)-Sulpiride, though a rather weak antagonist of ergometrine (Ki congruent to 6150 nM), was ineffectual as a dopamine blocker, indicating distinct receptor sites on this epithelium for dopamine and ergometrine. Both (+)-butaclamol and sulpiride reversed the autoinhibition associated with supramaximal levels of dopamine. Sulpiride also abolished spiperone's potentiation of dopamine. Butaclamol, on the other hand, had no such effect on spiperone's potentiation of dopamine. Finally, although the CNS of ticks contains both dopamine and noradrenaline in quantity (congruent to 650 and congruent to 370 ng . g-1 res respectively), the salivary glands contain far more dopamine than noradrenaline (congruent to 85 and congruent to 6 ng . g-1 respectively). The data support the hypothesis that dopamine is a natural transmitter substance in the tick salivary gland, and that there are distinct receptor sites in the epithelium mediating the actions of catecholamines, ergot alkaloids and butyrophenones. The physiological significance of the ergot alkaloid and butyrophenone sites is not clear.
利用孤立的希伯来花蜱（Amblyomma hebraeum Koch）唾液腺，我们测试了布他拉莫和舒必利在阻断多种激动剂刺激的液体分泌方面的有效性。（+）-布他拉莫是多巴胺、N-甲基多巴胺和去甲肾上腺素的强效抑制剂（Ki约为30 - 60 nM），但对麦角新碱的抑制效果较差（Ki约为310 nM）。反苯环丙胺在不存在和存在（+）-布他拉莫及（±）-舒必利的情况下刺激液体分泌，这表明反苯环丙胺的作用是通过两种受体介导的。（±）-舒必利虽然是麦角新碱的较弱拮抗剂（Ki约为6150 nM），但作为多巴胺阻断剂无效，这表明该上皮细胞上多巴胺和麦角新碱有不同的受体位点。（+）-布他拉莫和舒必利都能逆转与超最大剂量多巴胺相关的自身抑制。舒必利还消除了螺哌隆对多巴胺的增强作用。另一方面，布他拉莫对螺哌隆增强多巴胺的作用没有这种影响。最后，虽然蜱的中枢神经系统中多巴胺和去甲肾上腺素含量都很高（分别约为650和370 ng·g-1），但唾液腺中多巴胺含量远高于去甲肾上腺素（分别约为85和6 ng·g-1）。这些数据支持以下假说：多巴胺是蜱唾液腺中的天然递质物质，并且上皮细胞中有不同的受体位点介导儿茶酚胺、麦角生物碱和丁酰苯类的作用。麦角生物碱和丁酰苯类位点的生理意义尚不清楚。
