Martin J V, Edwards E, Johnson J O, Henn F A
Department of Biology, Rutgers University, Camden, New Jersey.
J Neurochem. 1990 Oct;55(4):1142-8. doi: 10.1111/j.1471-4159.1990.tb03117.x.
After a relatively mild course of uncontrollable shocks, two distinct groups of rats can be defined in terms of their performance in learning to escape from a controllable stressor. Response-deficient (RD) rats do not learn to terminate the controllable stressor, whereas nondeficient (ND) rats learn this response as readily as do untreated control rats. The current studies were designed to determine the neurochemical correlates of the behavioral differences between these groups of rats. The major findings concerned postsynaptic beta-adrenergic effects in the hippocampus of RD rats. These included an up-regulation of beta-adrenergic receptors and, in parallel experiments, an increase in the sensitivity of adenylyl cyclase to stimulation by norepinephrine. There was no difference in brain levels of catecholamines between the three groups of rats. A statistically significant increase in levels of 5-hydroxytryptamine was noted in the hippocampus and hypothalamus of RD rats as compared to levels in ND rats, but no significant differences were measured between groups of rats in terms of S1 or S2 serotonergic receptor binding. These results implicate both beta-adrenergic and serotonergic mechanisms in the behavioral deficit caused by uncontrollable shock.
在经历了相对温和的无法控制的电击过程后，根据大鼠在学习逃避可控应激源时的表现，可以区分出两组不同的大鼠。反应缺陷（RD）大鼠学不会终止可控应激源，而非缺陷（ND）大鼠学会这种反应的速度与未处理的对照大鼠一样快。当前的研究旨在确定这两组大鼠行为差异的神经化学相关性。主要发现涉及RD大鼠海马体中的突触后β-肾上腺素能效应。这些效应包括β-肾上腺素能受体的上调，并且在平行实验中，腺苷酸环化酶对去甲肾上腺素刺激的敏感性增加。三组大鼠的脑内儿茶胺水平没有差异。与ND大鼠相比，RD大鼠海马体和下丘脑的5-羟色胺水平有统计学意义的升高，但在大鼠组之间，S1或S2血清素能受体结合方面没有测量到显著差异。这些结果表明，β-肾上腺素能和血清素能机制都与无法控制的电击所导致的行为缺陷有关。
