四氢小檗碱的中枢抑制作用与GABA受体无关

应用蚯蚓背肌收缩反应，证实四氢小檗碱（ＴＨＢ，１０－７－１０－４ｍｏｌ／Ｌ）不能影响ＧＡＢＡ和ＡＣｈ两种受体的功能，多巴胺受体阻滞剂氟哌啶醇（ＨＡＬ）亦不能影响它们。由于异烟肼（ＩＮＨ）和氨基硫脲（ＴＳＣ）抑制ＧＡＢＡ的生物合成，印防己毒素（ＰＴ）和毕枯枯灵（Ｂｉｃ）作用于ＧＡＢＡ－ＢＺ受体复合体，它们都使小鼠产生惊厥，该作用能被氨基氧乙酸（ＡＯＡＡ）和安定（ＢＺ）所拮抗，但ＴＨＢ和ＨＡＬ却不能。由此表明前述ＴＨＢ的中枢抑制作用与ＧＡＢＡ抑制无关。

ON THE CENTRAL INHIBITION ACTION OF TETRAHYDROBERBHRINE WITHOUT RELEVANCE TO GABA RECEPTORS

Using an earthworm (Eisenia foetida) dorsal muscle preparation[6], it was shown that tetrahydroberberine (THB, 10-7- 10-4 mol/L) did not affect both GABA and ACh receptors. DA receptor antagonist haloperidol (HAL) also exerted no effect.Owing to the blocking action of isonicotinyl hydrazine (INH) and thiosemicarbazide (TSC) on biosynthesis of GABA, and of picrotoxin (PT) and bicuculline (Bic)on the GABA-BZ receptor complex mediated transmission, all these agents could induce convulsion in mice. This action could be antagonized by amino-oxyacetic acid (AOAA) and benzodiazepine (BZ), but not by DA receptor antagonists THB and HAL. All the above observations indicate that the GABA inhibition is not involved in the central action of THB.