Racké K, Holzbauer M, Cooper T R, Sharman D F
Neuroendocrinology. 1986;43(1):6-11. doi: 10.1159/000124501.
The effect of dehydration on dopamine (DA) release from the neural and intermediate lobes of the rat pituitary gland after electrical stimulation of the pituitary stalk was studied in vitro. The amount of DA released from pituitary lobes of dehydrated rats (no water for 72 h), in which the hormone secretion from the hypophysis, especially the neural lobe, is known to be greatly enhanced, was significantly higher when compared with that from control tissues. In control and dehydrated rats the evoked DA release from the intermediate lobe was higher than that from the neural lobe. After dehydration, the stimulus-evoked DA release from the neural lobe increased by more than 200%, whereas that from the intermediate lobe increased by only 60%, indicating a preferential activation of the DA system of the neural lobe. There was a decrease in DA released per pulse from the combined neuro-intermediate lobe of control rats with increasing number of stimulation pulses. In contrast, DA release per pulse from the neuro-intermediate lobe of dehydrated rats showed a tendency to increase with increasing number of pulses. As the availability of newly synthesized DA is believed to be the limiting factor for transmitter release, the present observations suggested a higher in vitro DA synthesis rate in the tissues from dehydrated rats. This agrees with in vivo results of Alper and his colleagues who found an increased accumulation of L-3,4-dihydroxyphenylalanine (DOPA) in neuro-intermediate lobes of dehydrated rats after inhibition of DOPA-decarboxylase.
在体外研究了脱水对电刺激垂体柄后大鼠垂体神经叶和中间叶多巴胺（DA）释放的影响。已知垂体，特别是神经叶的激素分泌在脱水大鼠（72小时不饮水）中会大大增强，与对照组织相比，脱水大鼠垂体叶释放的DA量显著更高。在对照大鼠和脱水大鼠中，中间叶诱发的DA释放高于神经叶。脱水后，神经叶刺激诱发的DA释放增加了200%以上，而中间叶仅增加了60%，表明神经叶的DA系统优先被激活。随着刺激脉冲数的增加，对照大鼠神经-中间叶组合每脉冲释放的DA减少。相反，脱水大鼠神经-中间叶每脉冲释放的DA随脉冲数增加有增加的趋势。由于新合成的DA的可用性被认为是递质释放的限制因素，目前的观察结果表明脱水大鼠组织中体外DA合成率更高。这与Alper及其同事的体内结果一致，他们发现抑制多巴脱羧酶后，脱水大鼠神经-中间叶中L-3,4-二羟基苯丙氨酸（DOPA）的积累增加。
