The effects of the histamine H3 receptor ligands thioperamide and (R)-α-methylhistamine on the histidine decarboxylase (HDC) activity and histamine content of mouse brain were examined. Thioperamide, a histamine H3 antagonist, significantly increased the HDC activity in the brain of ddY, W/Wv and ICR mice 2-6 hr after its intraperitoneal (i.p.) injection. On the other hand, (R)-α-methylhistamine, a histamine H3-receptor agonist, caused no significant change in the HDC activity. The whole brain histamine content of ddY mice decreased significantly to 60-70 % of the control level 2-8 hr after injection of thioperamide (25 mg/kg, i.p), but then increased to 90 % of the control level 10 hr after the injection. These in vivo results showed that blockade of the presynaptic histamine H3-receptor, which causes release of presynaptic histamine, increased the HDC activity.
|ジャーナル||Biochemical and biophysical research communications|
|出版ステータス||Published - 1992 5 29|
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