Johnson D G, Thoa N B, Weinshilboum R, Axelrod J, Kopin I J
Proc Natl Acad Sci U S A. 1971 Sep;68(9):2227-30. doi: 10.1073/pnas.68.9.2227.
Dopamine-beta-hydroxylase (EC 1.14.2.1), an enzyme localized in sympathetic synaptic vesicles, was released together with norepinephrine during in vitro stimulation of the hypogastric nerve that innervates the vas deferens of the guinea pig. Stimulation of the nerve in the presence of high concentrations of calcium (7.5 mM) or phenoxybenzamine caused a marked increase in the amounts of the enzyme and norepinephrine released into the bath. The augmentation of release of dopamine-beta-hydroxylase by 7.5 mM calcium or phenoxybenzamine was reversed by prostaglandin E(2). These findings suggest that the release of the sympathetic neurotransmitter, norepinephrine, occurs by a process of exocytosis in which the vesicular content of soluble dopamine-beta-hydroxylase is also released. The depolarization-induced exocytosis, which is stimulated by calcium, may be affected by prostaglandin E(2) or phenoxybenzamine through inhibition or enhancement of the actions of calcium in the release process.
多巴胺-β-羟化酶（EC 1.14.2.1）是一种定位于交感神经突触小泡的酶，在体外刺激支配豚鼠输精管的腹下神经时，它与去甲肾上腺素一起被释放出来。在高浓度钙（7.5 mM）或酚苄明存在的情况下刺激神经，会导致释放到浴槽中的该酶和去甲肾上腺素的量显著增加。前列腺素E2可逆转7.5 mM钙或酚苄明引起的多巴胺-β-羟化酶释放增加。这些发现表明，交感神经递质去甲肾上腺素的释放是通过胞吐作用进行的，在此过程中可溶性多巴胺-β-羟化酶的小泡内容物也会被释放。由钙刺激的去极化诱导的胞吐作用，可能会受到前列腺素E2或酚苄明的影响，它们通过抑制或增强钙在释放过程中的作用来实现。
