Matos F F, Rollema H, Basbaum A I
Department of Anatomy and Physiology, University of California, San Francisco 94143.
J Neurochem. 1992 May;58(5):1773-81. doi: 10.1111/j.1471-4159.1992.tb10053.x.
In this report, we describe an HPLC with electrochemical detection assay for the simultaneous measurement of levels of morphine, serotonin, 5-hydroxyindole-3-acetic acid, and homovanillic acid in dialysates of various brain areas and CSF in the awake rat. Morphine could be detected in the dialysates after a single intraperitoneal injection, with doses as low as 1.0 mg/kg. The time course of extracellular morphine content in the lateral hypothalamus, striatum, cerebellum, periaqueductal gray, and dorsal horn of the spinal cord and in CSF, from the ventricles and cisterna magna, was similar. We detected morphine in the first 15-min sample, and levels peaked 45-60 min after injection. Maximal dialysate levels, however, varied with the type of dialysis probe used and the area sampled. The most efficient in vivo recovery was in CSF dialysates from the cisterna magna, presumably because of minimal tissue interference with the dialysis probe. For this reason, the cisterna is an ideal region for sampling CSF. Morphine had no significant effect on the extracellular concentrations of serotonin in any of the areas studied and did not modify or only slightly increased levels of tissue metabolites; however, morphine markedly increased the CSF levels of 5-hydroxyindole-3-acetic acid and homovanillic acid. Because microdialysis in freely moving animals permits assessment of the behavioral effects of morphine while continuously monitoring the drug levels in discrete brain regions, this approach will greatly facilitate future studies of the neurochemical basis of morphine's effects in the brain.
在本报告中，我们描述了一种采用电化学检测的高效液相色谱法，用于同时测量清醒大鼠不同脑区透析液和脑脊液中吗啡、血清素、5-羟色胺-3-乙酸和高香草酸的水平。单次腹腔注射后，在透析液中可检测到吗啡，最低剂量为1.0mg/kg。下丘脑外侧区、纹状体、小脑、导水管周围灰质、脊髓背角以及脑室和枕大池脑脊液中细胞外吗啡含量的时间进程相似。在注射后15分钟的样本中我们检测到了吗啡，其水平在注射后45-60分钟达到峰值。然而，最大透析液水平因所用透析探针的类型和采样区域而异。体内回收率最高的是枕大池的脑脊液透析液，这可能是因为组织对透析探针的干扰最小。因此，枕大池是采集脑脊液的理想区域。在所研究的任何区域中，吗啡对血清素的细胞外浓度均无显著影响，对组织代谢物水平也未改变或仅略有升高；然而，吗啡显著提高了5-羟色胺-3-乙酸和高香草酸的脑脊液水平。由于对自由活动动物进行微透析可以在连续监测离散脑区药物水平的同时评估吗啡的行为效应，这种方法将极大地促进未来对吗啡在脑中作用的神经化学基础的研究。
