Singewald N, Philippu A
Institut für Pharmacokologie und Toxikologie, Universität Innsbruck, Austria.
Naunyn Schmiedebergs Arch Pharmacol. 1993 Jan;347(1):21-7. doi: 10.1007/BF00168767.
The involvement of catecholaminergic neurons of the locus coeruleus in central cardiovascular control was investigated in the anaesthetized cat. Push-pull cannulae were bilaterally inserted into the LC and the release of noradrenaline and dopamine was determined radioenzymatically in the superfusate. The effects of experimentally induced changes in blood volume and vascular resistance on catecholamine release in the locus coeruleus were studied. Hypervolaemia strongly inhibited the release of noradrenaline in the locus coeruleus. Intravenous infusion of noradrenaline (5 micrograms.kg-1.min-1) elicited a pronounced pressor response which was also associated with a decrease in the release of noradrenaline in the locus coeruleus. Conversely, a fall of blood pressure caused by a controlled haemorrhage enhanced the release of noradrenaline. A profound fall in blood pressure caused by infusion of nitroprusside (8 micrograms.kg-1.min-1) did not modify the release rate of noradrenaline. Dopamine release rate was not significantly influenced by these cardiovascular alterations. The results demonstrate that increases in blood pressure elicited by vascular constriction or hypervolaemia inhibit the release of noradrenaline in the locus coeruleus. Decreases in blood pressure elicited by hypovolaemia enhance the release of noradrenaline, but lowering blood pressure by vasodilatation is ineffective. Hence, the release of endogenous noradrenaline in the locus coeruleus is responsive to haemodynamic signals, thus supporting the suggested integrative role of the locus coeruleus in central cardiovascular control.
在麻醉猫身上研究了蓝斑去甲肾上腺素能神经元在中枢心血管控制中的作用。将推挽式套管双侧插入蓝斑，并用放射酶法测定灌流液中去甲肾上腺素和多巴胺的释放量。研究了实验性诱导的血容量和血管阻力变化对蓝斑中儿茶酚胺释放的影响。血容量过多强烈抑制蓝斑中去甲肾上腺素的释放。静脉输注去甲肾上腺素（5微克·千克⁻¹·分钟⁻¹）引起明显的升压反应，这也与蓝斑中去甲肾上腺素释放量的减少有关。相反，控制性出血引起的血压下降增强了去甲肾上腺素的释放。硝普钠（8微克·千克⁻¹·分钟⁻¹）输注引起的血压大幅下降并未改变去甲肾上腺素的释放速率。多巴胺释放速率不受这些心血管改变的显著影响。结果表明，血管收缩或血容量过多引起的血压升高抑制蓝斑中去甲肾上腺素的释放。血容量不足引起的血压下降增强去甲肾上腺素的释放，但通过血管舒张降低血压无效。因此，蓝斑中内源性去甲肾上腺素的释放对血流动力学信号有反应，从而支持了蓝斑在中枢心血管控制中所提出的整合作用。
