Alexandrova M, Holzbauer M, Racke K, Sharman D F
Neuroscience. 1987 May;21(2):421-7. doi: 10.1016/0306-4522(87)90132-1.
Specific acetylcholinesterase and non-specific cholinesterases are present in all three lobes of the rat pituitary gland. This paper describes two new observations on hypophyseal acetylcholinesterase. Firstly, a prolonged increase of neurohormone secretion evoked by dehydration and sodium loading was accompanied by a decrease in the acetylcholinesterase activity localized to the neural lobe, where acetylcholinesterase has previously been demonstrated in fine nerve fibres. Secondly, electrical stimulation of the pituitary stalk in vitro elicited the release of acetylcholinesterase and non-specific cholinesterases from the combined neural and intermediate lobe indicating that the enzyme can be released from nerve endings in the hypophysis by action potentials. The observed loss of enzyme activity during dehydration may be the consequence of a prolonged activation of cholinergic nerves in the gland, leading to an increased release of acetylcholinesterase, which is not immediately replaced by fresh enzyme. The decrease in acetylcholinesterase in the neural lobe during dehydration may also be connected with its peptidase function and thus with the previously observed loss of substance P from the neural lobe during dehydration [Holzbauer et al. (1984) Neurosci. Lett. 47, 23-28].
大鼠垂体的所有三个叶中均存在特异性乙酰胆碱酯酶和非特异性胆碱酯酶。本文描述了关于垂体乙酰胆碱酯酶的两项新观察结果。首先，脱水和钠负荷引起的神经激素分泌长期增加，伴随着神经叶中乙酰胆碱酯酶活性的降低，此前已在细神经纤维中证实神经叶存在乙酰胆碱酯酶。其次，体外电刺激垂体柄可引起神经叶和中间叶联合释放乙酰胆碱酯酶和非特异性胆碱酯酶，这表明该酶可通过动作电位从垂体的神经末梢释放。脱水过程中观察到的酶活性丧失可能是腺体中胆碱能神经长期激活的结果，导致乙酰胆碱酯酶释放增加，而新鲜酶不能立即补充。脱水过程中神经叶中乙酰胆碱酯酶的减少也可能与其肽酶功能有关，从而与先前观察到的脱水过程中神经叶中P物质的丧失有关[霍尔兹鲍尔等人（1984年）《神经科学快报》47卷，23 - 28页]。
