Daily dose effect of valerian root extract on some neurotransmitter contents in different brain areas of male albino rats

الملخص EN

The aim of the present study was to investigate the daily effect of valerian (Valeriana officinalis L .) root extract on epinephrine (E), norepinephrine (NE) , dopamine (DA), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), and gamma-aminobutyric acid (GABA) contents in different brain areas (cerebellum, pons plus medulla oblongata, striatum, cerebral cortex, hypothalamus, midbrain and hippocampus) of male albino rats.The daily intraperitoneal ( i.p.) injection of 300 mg / kg body wt valerian for 30 days caused a significant increase in epinephrine ( E ) content in pons plus medulla oblongata, cerebral cortex, hypothalamus and in midbrain.

Norepinephrine (NE) content was significantly increased in all brain areas tested except in cerebellum and cerebral cortex.

Dopamine (DA) content was significantly increased in all tested brain areas except in cerebral cortex and hippocampus.

moreover, there was also a significant increase in serotonin (5-HT ) and 5-hydroxyindol acetic acid (5-HIAA) contents in all tested brain areas .

However, gamma-aminobutyric acid (GABA) content was significantly decreased in all tested brain areas.

After the extract withdrawal, the increase in ( E, NE, DA, 5-HT ) contents and the decrease in GABA content persisted in pons plus medulla oblongata, striatum, midbrain and hippocampus, and this might be due to regional differences toward the effect.

The increase in E, NE, DA, 5-HT and 5-HIAA contents, at the same time the decrease in GABA content in the different brain areas of albino rats may be due to the presence of both valepotriates and valerenic acid in the extract which mediated the GABA ergic mechanisms including the inhibition of GABA metabolism and the increase in GABA synthesis and release, although agonized the GABAA receptors which led to the inhibit of the neurotransmitter release.

Valerian root extract may be useful as a herbal medicine having sedative effect and it is safe.