Bjerre B, Björklund A, Mobley W, Rosengren E
Brain Res. 1975 Aug 29;94(2):263-77. doi: 10.1016/0006-8993(75)90061-x.
Nerve growth factor (NGF) induced a marked increase in the adrenergic nerve terminal networks of several peripheral organs in intact adult and young adult mice. The animals were investigated at 3 days and at 2 months after 6 daily subcutaneous injections of the 7S species of NGF (1 mug/g body weight each dose). At 3 days after the end of the treatment an increased fluorescence intensity, as well as an increased density of the adrenergic terminal plexuses was observed by fluorescence histochemical techniques in iris, salivary glands, heart, intestine, spleen and pancreas. These changes were paralleled by significant increases (up to 55%) in the endogenous NA levels. Increased NA levels were also detected in the brain of the NGF-treated animals. At 2 months after treatment the effects had almost totally disappeared, demonstrating that the NGF-induced overgrowth of the sympathetic axons was only temporary. The increased adrenergic innervation probably resulted from a stimulatory effect of NGF on collateral sprouting from the intact adrenergic axons. In line with the idea that the terminals of peripheral axons are continuously renewed, it is suggested that endogenous NGF could play a regulatory role in such a continuous growth process of the fully developed, adult sympathetic nervous system, directed at the maintenance of an adequate adrenergic terminal network.
神经生长因子（NGF）可使成年和幼年完整小鼠的多个外周器官的肾上腺素能神经终末网络显著增加。在每日皮下注射7S型NGF（每剂1微克/克体重），连续注射6天后，分别在3天和2个月时对动物进行研究。在治疗结束后3天，通过荧光组织化学技术观察到虹膜、唾液腺、心脏、肠道、脾脏和胰腺中荧光强度增加，以及肾上腺素能终末丛密度增加。这些变化伴随着内源性去甲肾上腺素（NA）水平显著升高（高达55%）。在接受NGF治疗的动物大脑中也检测到NA水平升高。治疗后2个月，这些效应几乎完全消失，表明NGF诱导的交感神经轴突过度生长只是暂时的。肾上腺素能神经支配增加可能是由于NGF对完整肾上腺素能轴突的侧支发芽具有刺激作用。鉴于外周轴突的终末不断更新，有人提出内源性NGF可能在完全发育的成年交感神经系统的这种持续生长过程中发挥调节作用，以维持适当的肾上腺素能终末网络。
