甲基多巴在正常大鼠和免疫交感神经切除大鼠中的降压作用机制。

Mechanism of the hypotensive action of methyldopa in normal and immunosympathectomized rats.

Ayitey-Smith E, Varma D R

Br J Pharmacol. 1970 Oct;40(2):186-93. doi: 10.1111/j.1476-5381.1970.tb09912.x.

Abstract

The antihypertensive action of methyldopa was investigated in the light of the prevailing false sympathetic neurotransmitter hypothesis of Day & Rand (1963). Immunosympathectomized and normal animals were used for the investigation.2. Methyldopa in a single injection significantly decreased the blood pressure in control hypertensive, immunosympathectomized normotensive, and normal rats. Guanethidine did not decrease the blood pressure of immunosympathectomized rats; it decreased the blood pressure of control and control hypertensive rats.3. The hypotensive effect of methyldopa was not antagonized by adrenoceptor and ganglion blocking agents or by the inhibition of dopamine beta-oxidase.4. High doses of methyldopa produced less hypotension than relatively low doses. This might be due to an antagonism of the hypotensive effect by methylnoradrenaline, which is formed from methyldopa.5. The antihypertensive action of methyldopa could not be correlated with any change in aortic sodium or potassium.6. It is concluded that methyldopa does not exert its hypotensive effect by producing a weakly active false sympathetic neurotransmitter.

摘要

根据戴伊和兰德（1963年）流行的假性交感神经递质假说，对甲基多巴的降压作用进行了研究。使用免疫交感神经切除的动物和正常动物进行该研究。
单次注射甲基多巴可显著降低对照高血压大鼠、免疫交感神经切除的正常血压大鼠和正常大鼠的血压。胍乙啶不会降低免疫交感神经切除大鼠的血压；它可降低对照大鼠和对照高血压大鼠的血压。
甲基多巴的降压作用不受肾上腺素能受体阻断剂、神经节阻断剂或多巴胺β氧化酶抑制的拮抗。
高剂量甲基多巴产生的低血压比相对低剂量时少。这可能是由于由甲基多巴形成的甲基去甲肾上腺素对降压作用的拮抗。
甲基多巴的降压作用与主动脉钠或钾的任何变化均无关联。
得出的结论是，甲基多巴并非通过产生活性较弱的假性交感神经递质来发挥其降压作用。