Schaad N C, Vanecek J, Kosar E, Aubry J M, Schulz P E
Department of Psychiatry, Geneva University Medical School, Chêne-Bourg, Switzerland.
J Neurochem. 1995 Aug;65(2):935-8. doi: 10.1046/j.1471-4159.1995.65020935.x.
We have previously shown that exposure of rats to constant light (LL) induced a decrease in NO synthase (NOS) activity in the pineal gland. We present here the evidence that chronic (5 days) norepinephrine (NE) or isoproterenol treatment prevents the effect of LL and enhances pineal NOS activity in LL animals. This effect of NE appears to be mediated by beta-adrenoceptors, because it was not mimicked by the alpha-agonist phenylephrine. Pineal NOS activity was reduced in 16-h light/8-h dark animals treated for 4 days with the beta-adrenergic antagonist propranolol but not with the alpha 1-antagonist prazosin, indicating again an involvement of beta-adrenergic receptor in the control of NOS. Treatment with adrenergic antagonists did not affect cortical NOS activity, suggesting that the control of NOS is different in these two tissues or that the pineal expresses a specific isoform of the enzyme. Taken together, these data suggest that NE controls NOS in the pineal gland through beta-adrenergic receptors. To our knowledge, this represent the first demonstration of a regulation of NOS by a neurotransmitter in the CNS, as assayed under Vmax conditions.
我们之前已经表明，将大鼠暴露于持续光照（LL）会导致松果体中一氧化氮合酶（NOS）活性降低。我们在此提供证据表明，慢性（5天）去甲肾上腺素（NE）或异丙肾上腺素处理可预防LL的影响，并增强LL动物的松果体NOS活性。NE的这种作用似乎是由β-肾上腺素能受体介导的，因为α-激动剂去氧肾上腺素无法模拟这种作用。用β-肾上腺素能拮抗剂普萘洛尔处理4天的16小时光照/8小时黑暗动物的松果体NOS活性降低，但用α1-拮抗剂哌唑嗪处理则没有，这再次表明β-肾上腺素能受体参与了NOS的控制。用肾上腺素能拮抗剂处理不会影响皮质NOS活性，这表明这两个组织中NOS的控制方式不同，或者松果体表达该酶的一种特定同工型。综上所述，这些数据表明NE通过β-肾上腺素能受体控制松果体中的NOS。据我们所知，这是在Vmax条件下测定时，首次证明中枢神经系统中神经递质对NOS的调节作用。
