Lightman S L, Iversen L L, Forsling M L
J Neurosci. 1982 Jan;2(1):78-81. doi: 10.1523/JNEUROSCI.02-01-00078.1982.
The effects of both dopamine and enkephalin agonists were assessed on electrically stimulated vasopressin secretion from the isolated neural lobe. Both dopamine (10(-6) M) and the dopamine agonist ADTN (2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene; 10(-6) M) significantly reduced the stimulated release of vasopressin. This reduction in vasopressin secretion was prevented by the dopamine antagonist sulpiride (10(-6) M). [D-Ala2, D-Leu5]Enkephalin (DADLE) also inhibited vasopressin release and its effect was additive to that of ADTN. The effect of DADLE was prevented by the opiate antagonist naloxone and was also sensitive to the calcium content of the medium. Low calcium concentrations markedly increased the inhibitory effect of DADLE, while high concentrations abolished its effect. These findings provide evidence of a direct inhibitory action of both dopamine and enkephalins at the level of the neural lobe and suggest that the effect of enkephalins may be intimately related to calcium-sensitive neurosecretory events.
研究评估了多巴胺和脑啡肽激动剂对离体神经叶电刺激引起的血管加压素分泌的影响。多巴胺（10⁻⁶ M）和多巴胺激动剂ADTN（2-氨基-6,7-二羟基-1,2,3,4-四氢萘；10⁻⁶ M）均显著降低了血管加压素的刺激释放。多巴胺拮抗剂舒必利（10⁻⁶ M）可防止血管加压素分泌的这种减少。[D-Ala²，D-Leu⁵]脑啡肽（DADLE）也抑制血管加压素释放，其作用与ADTN的作用相加。DADLE的作用可被阿片拮抗剂纳洛酮阻断，并且对培养基中的钙含量敏感。低钙浓度显著增强了DADLE的抑制作用，而高钙浓度则消除了其作用。这些发现提供了多巴胺和脑啡肽在神经叶水平上直接抑制作用的证据，并表明脑啡肽的作用可能与钙敏感的神经分泌事件密切相关。
