Wakade A R
Department of Pharmacology, State University of New York, Health Science Center at Brooklyn 11203.
J Neurochem. 1988 Apr;50(4):1302-8. doi: 10.1111/j.1471-4159.1988.tb10608.x.
The effect of continuous stimulation of splanchnic nerves at 1, 3, and 10 Hz on the secretion of catecholamines from the isolated rat adrenal gland was examined. Secretion evoked at 10 Hz declined over 60% in 1 h, and by the end of 4 h the secretion was only 10% of the initial value. The secretion evoked at 3 Hz was unchanged in the first hour, but showed a gradual decline in subsequent hours. In contrast, secretion evoked at 1 Hz was well maintained for several hours. Even after 6 h of continuous stimulation, the decline was only about 35%. Atropine plus hexamethonium reduced the secretion evoked at 10 Hz by over 80%, but that evoked at 1 Hz was reduced by about 35%; addition of naloxone reduced it to 75%. When the secretion declined to very low levels after continuous stimulation at 10 Hz for 100 min, a change in frequency to 3 Hz or 1 Hz caused a sharp rebound in the secretory response. Returning the frequency back to 10 Hz led to a sharp drop in the secretion, whereas reducing the frequency to 1 or 3 Hz once again increased the secretion. The rebound in the secretory response after switchover of frequencies was observed in the presence of atropine plus hexamethonium, but was abolished by naloxone. Extensive stimulations, which caused large amounts of catecholamine secretions at each frequency, were not associated with any loss in tissue catecholamine contents. The major conclusion is that secretion of catecholamines is maintained uninterrupted for several hours when splanchnic nerves are stimulated at low frequency.(ABSTRACT TRUNCATED AT 250 WORDS)
研究了以1、3和10Hz频率持续刺激内脏神经对离体大鼠肾上腺髓质儿茶酚胺分泌的影响。10Hz刺激引起的分泌在1小时内下降超过60%，4小时结束时分泌仅为初始值的10%。3Hz刺激引起的分泌在第一小时不变，但在随后的几小时内逐渐下降。相比之下，1Hz刺激引起的分泌在数小时内保持良好。即使连续刺激6小时，下降也仅约35%。阿托品加六甲铵使10Hz刺激引起的分泌减少超过80%，但1Hz刺激引起的分泌减少约35%；加入纳洛酮后减少至75%。当以10Hz连续刺激100分钟后分泌降至非常低的水平时，频率改变为3Hz或1Hz会导致分泌反应急剧反弹。将频率恢复到10Hz会导致分泌急剧下降，而将频率降低到1Hz或3Hz会再次增加分泌。在阿托品加六甲铵存在的情况下观察到频率切换后分泌反应的反弹，但被纳洛酮消除。大量刺激在每个频率下引起大量儿茶酚胺分泌，但与组织儿茶酚胺含量的任何损失无关。主要结论是，当以低频刺激内脏神经时，儿茶酚胺的分泌可连续数小时保持不间断。（摘要截断于250字）
