Cam G R, Bassett J R
Pharmacol Biochem Behav. 1984 Feb;20(2):221-6. doi: 10.1016/0091-3057(84)90246-6.
Daily IP injections of nicotine (200 micrograms/kg body weight) resulted in an adaptation of the nicotine induced rise in plasma corticosterone. By 30 days the plasma corticosterone rise was not significantly different from that seen in control animals receiving an injection of saline. A similar adaptation to the plasma corticosterone response to the stress of signalled, irregular footshock was also observed. However, in the case of the exposure to stress, while the corticosterone response at day 40 was significantly less than the response seen on day 1, it was still significantly greater than the plasma corticosterone level from unstressed control animals. Cross-adaptation experiments were conducted in which animals were adapted to the steroidogenic action of nicotine and then subjected to a novel exposure to footshock stress, and vice versa. In both situations the animals responded to the novel stimulus, either stress or nicotine, with a significant rise in plasma corticosterone. It was postulated that nicotine and psychological stress act upon the hypothalamo-pituitary-adrenal axis via functionally separate pathways at the level of the corticotrophin releasing factor neuron. The separate pathways appear to differ in their ability to be inhibited by corticosterone feedback.
每日腹腔注射尼古丁（200微克/千克体重）导致对尼古丁诱导的血浆皮质酮升高产生适应性变化。到第30天时，血浆皮质酮的升高与接受盐水注射的对照动物相比无显著差异。还观察到对有信号的不规则足部电击应激的血浆皮质酮反应有类似的适应性变化。然而，在暴露于应激的情况下，虽然第40天时的皮质酮反应明显低于第1天时的反应，但仍明显高于未受应激的对照动物的血浆皮质酮水平。进行了交叉适应性实验，即让动物先适应尼古丁的类固醇生成作用，然后再进行新的足部电击应激暴露，反之亦然。在这两种情况下，动物对新刺激（应激或尼古丁）的反应都是血浆皮质酮显著升高。据推测，尼古丁和心理应激通过促肾上腺皮质激素释放因子神经元水平上功能上独立的途径作用于下丘脑-垂体-肾上腺轴。这两条独立的途径在被皮质酮反馈抑制的能力上似乎有所不同。
