Imipramine이 백서의 임파구 베타 아드레날린 수용체 결합과 혈장 3-Methoxy-4-Hydroxyphenylglycol(MHPG)농도에 미치는 영향에 관한 연구

The Effects of Imipramine on the Lymphocyte Beta-Adrenergic Receptor Binding and Plasma Level of 3-Methoxy-4-Hydroxyphenylglycol(MHPG) in Rats

Objects • The levels of plasma MH PG and the beta-adrenergic receptors of the peripheral lymphocytes were investigated at various times during chronic administration of imipramine. And the relationship between these peripheral measures and the central noradrenergic activities (MHPG levels and beta-adrenergic receptor bindings in the cerebral cortex) which were measured simultaneously with this expriment were studied. The purpose of this experiment was to know whether the peripheral measures reflect the central noradrenergic activities. And also the relationship between the levels of plasma MHPG and the beta-adrenergic receptors of the peripheral lymphocytes were investigated. Method : The levels of MHPG in plasma were measured by high performance liquid chromatography with electrochemical detector(HPLC-ECD). Beta-adrenergic receptors of the peripheral lymphocytes were assayed by 3H-dihydroalprenolol(3H-DHA) ligand bindings. Results: 1) A short term administration of imipramine decreased the level of plasma MHPG while increase in plasma MHPG level was shown by long term (2 weeks) administraion, both of which were statistically significant 2) A significant increase in the number(Bmax) of lymphocyte beta-adrenergic receptors was observed after a 5 week, administration but the affinity (Kd) did not change significantly. 3) A positive correlation was noted between the change in plasma M H PG level and that in beta-adrenergic receptors which was not statistically significant 4) A positive correlation was noted between the change in plasma M H PG level and that in M H PG level in cerebral cortex, but it was not statistically significant 5) A strong negative correlation was noted between the beta-adrenergic receptor numbers (Bmax) of cerebral cortex and that of lymphocytes, but it was not significant statistically. In summary, the possibility of plasma MHPG as a useful peripheral marker for central presynaptic noradrenergic activity was not ascertained because their parallel change was not statistically significant Conclusions : The lymphocyte beta-adrenergic receptor was not found to be a adequate marker for central beta-adrenergic receptors. Further studies will be necessary to find the exact meaning of the change in the lymphocyte beta-adrenergic receptors and their relations with those in the central nervous system as well as with the plasma noradrenergic activity.