Sarojini R, Nagabhushanam R, Fingerman M
Department of Ecology, Evolution, and Organismal Biology, Tulane University, New Orleans, Louisiana 70118.
Gen Comp Endocrinol. 1995 Jan;97(1):160-70. doi: 10.1006/gcen.1995.1015.
In in vivo experiments injection of dopamine (DA) or leucine enkephalin (L-Enk) produced hypoglycemia in intact red swamp crayfish, Procambarus clarkii. In contrast, neither compound had a significant effect on the circulating glucose concentration in eyestalkless individuals. With intact crayfish spiperone, a DA receptor blocker, inhibited this hypoglycemic action of DA but not this action of L-Enk. In contrast, in intact crayfish naloxone, a competitive opioid antagonist, inhibited the in vivo hypoglycemic actions of both L-Enk and DA. In vitro, both DA and L-Enk reduced the rate of release of the crustacean hyperglycemic hormone (CHH) from isolated eyestalk neuroendocrine tissue. These results suggest that both DA and L-Enk act to inhibit release of CHH by affecting the eyestalk neuroendocrine complex and that the enkephalinergic inhibitory neuron follows the dopaminergic inhibitory neuron in the chain of neurons which leads to the neuroendocrine cells that secrete CHH.
在体内实验中，向完整的克氏原螯虾（Procambarus clarkii）注射多巴胺（DA）或亮氨酸脑啡肽（L-Enk）会导致低血糖。相比之下，这两种化合物对无眼柄个体的循环葡萄糖浓度均无显著影响。对于完整的小龙虾，多巴胺受体阻滞剂螺哌隆抑制了多巴胺的这种降血糖作用，但不抑制亮氨酸脑啡肽的这种作用。相反，在完整的小龙虾中，竞争性阿片受体拮抗剂纳洛酮抑制了亮氨酸脑啡肽和多巴胺的体内降血糖作用。在体外，多巴胺和亮氨酸脑啡肽均降低了从分离的眼柄神经内分泌组织中释放的甲壳类高血糖激素（CHH）的速率。这些结果表明，多巴胺和亮氨酸脑啡肽均通过影响眼柄神经内分泌复合体来抑制CHH的释放，并且在通向分泌CHH的神经内分泌细胞的神经元链中，脑啡肽能抑制性神经元位于多巴胺能抑制性神经元之后。
