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

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

The effects of tricyclic antidepressant on the presynaptic and postsynaptic noradrenergic neurotransmission were studied at various times during chronic adm inistration of imipramine in rats. The purpose of this experiment was to investigate the therapeutic mechanism of imipramine. The levels of M H PG in cerebral cortex as the index of presynaptic noradrenergic activity were measured by high performance liquid chromatography with electrochemical detector (HPLC-ECD ). Postsynaptic beta-adrenergic receptors o f cerebral cortex were assayed by 3Hdihydroalprenolol( 3H-DHA) ligand bindings. The results were as follows; 1) The level of M H PG at cerebral cortex was decreased (statistically not significant) by the short term (l day) treatment of imiprmine. However a statistically significant increase was noted by the long term administration (3 weeks) in com parson to controls. 2) The num ber of maximal binding sites(Bmax) o f cerebral beta-adrenergic receptors was reduced significantly com pared to the controls after a 5 weeks adm inistration without significant concomitant change in the receptor affinity (Kd). 3) Although a strong negative correlation was noted between the change in M H PG level and beta-adrenergic receptor numbers (Bmax) in cerebral cortex, this was found to be statistically insignificant. In summary, long term administration of imipramine enhanced the presynaptic noradrenergic activity and reduced postsynaptic beta adrenergic receptor numbers. And these findings were thought to be related with the therapeutic mechanism of imipramine