Temple J G, Barthalmus G T
Department of Zoology, North Carolina State University, Raleigh 27695-7617.
Physiol Behav. 1994 May;55(5):927-33. doi: 10.1016/0031-9384(94)90081-7.
Skin mucus of the frog, Xenopus laevis, induces climbing and attenuates tongue flicking in Nerodia sipedon; these effects are induced alone and are potentiated by L-deprenyl, a monoamine oxidase type B inhibitor (MAO-Bi), but not by clorgyline, an MAO type A inhibitor (MAO-Ai). Both MAO-A and MAO-B metabolize dopamine, with MAO-B having the higher affinity; MAO-A selectively metabolizes serotonin and norepinephrine and MAO-B is selective for phenylethylamine. It was hypothesized that clorgyline and L-deprenyl would differentially modulate tongue flicking and climbing in frog-eating (Nerodia erythrogaster) and mammaphagous (Elaphe o. obsoleta) snakes, based on physiological differences between the species. L-Deprenyl caused a decrease in tongue flicking and climbing by Elaphe and an increase in climbing by Nerodia, whereas clorgyline did not alter tongue flicking, climbing, or locomotor activity in either species. To further assess the role of dopamine, hybrid black/gray rat snakes, E. o. spiloides, were administered the D1 and D2 dopamine receptor agonists SKF 77434 (SKF 38393, N-allyl) and quinpirole, respectively. SKF 77434 and quinpirole attenuated climbing, but only SKF 77434 attenuated tongue flicking in Experiment 3; neither drug affected locomotor activity. Results suggest that dopaminergic stimulation by MAO-Bi and dopamine agonists modulates tongue flicking and climbing behaviors in snakes, and that the contrasting climbing reactions induced by MAO-Bi between Elaphe and Nerodia may be linked to quantitative differences in endogenous catecholamine levels and/or to the numbers and sensitivity of receptors.
非洲爪蟾的皮肤黏液会诱导北美水蛇攀爬并减弱其吐舌动作；这些效应单独出现，且会被单胺氧化酶B型抑制剂（MAO - Bi）L - 司来吉兰增强，但不会被单胺氧化酶A型抑制剂（MAO - Ai）氯吉兰增强。MAO - A和MAO - B都可代谢多巴胺，其中MAO - B的亲和力更高；MAO - A选择性代谢5 - 羟色胺和去甲肾上腺素，而MAO - B对苯乙胺具有选择性。基于这两个物种的生理差异，推测氯吉兰和L - 司来吉兰会对食蛙蛇（红腹锦蛇）和食哺乳动物蛇（黑鼠蛇）的吐舌和攀爬行为产生不同的调节作用。L - 司来吉兰使黑鼠蛇的吐舌和攀爬行为减少，使北美水蛇的攀爬行为增加，而氯吉兰对这两个物种的吐舌、攀爬或运动活动均无影响。为了进一步评估多巴胺的作用，分别给杂交黑/灰鼠蛇（黑鼠蛇的一个亚种）注射D1和D2多巴胺受体激动剂SKF 77434（SKF 38393，N - 烯丙基）和喹吡罗。在实验3中，SKF 77434和喹吡罗均减弱了攀爬行为，但只有SKF 77434减弱了吐舌动作；两种药物均未影响运动活动。结果表明，MAO - Bi和多巴胺激动剂引起的多巴胺能刺激会调节蛇的吐舌和攀爬行为，并且MAO - Bi在黑鼠蛇和北美水蛇之间引起的相反攀爬反应可能与内源性儿茶酚胺水平的定量差异和/或受体的数量及敏感性有关。
