Effect of different depths of propofol anesthesia given by TCI on 5-HT metabolism in brain / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of different levels of propofol anesthesia on 5-HT metabolism in brain. Methods Forty Japanese Long-ear rabbits of both sexes, aged 8 months-2yr, weighing 2-3 kg were used for study. Anesthesia was induced and maintained with propofol administered by a TCI system. Blood propofol concentration required for different depths of anesthesia, as indicated by BIS monitoring and loss of chewing reflex (light anesthesia) and loss of response to tail nipped (deep anesthesia), was determined by high-performance liquid chromatography(HPLC) in 10 rabbits. Thirty rabbits were randomly divided into 3 groups often animals in each group: (1) control group received no propofol; (2) light anesthesia group and (3) deep anesthesia group. Different depths of propofol anesthesia were maintained for 1 h. At the end of one hour propofol anesthesia the animals were decapitated. Brain was immediately removed and cerebral cortex, hippocampus and thalamus were separated on ice. Their contents of 5-HT and 5-hydroxyindole-3-acetic acid (5-HIAA) were measured by spectrophoto-fluorometer.Results 5-HT content of cerebral cortex was significantly increased after anesthesia. 5-HT content of hippocampus and 5-HIAA content of thalamus decreased significantly with increasing anesthetic depth. Conclusion Propofol improves 5-HT activity in cerebral cortex and thalamus and decreases 5-HT activity in hippocampus indicating that 5-HT metabolism may be involved in the mechanism of propofol anesthesia.