Ephedrine and phenylephrine can treat the hypotension , however an amplified vasoconstrictive response may be observed due to an alpha 2 agonist induced enhancement of baroreceptor reflexes ( 7 ) and potentiation of alpha 1 - adrenoceptor - mediated vasoconstriction 麻黄素和苯肾上腺素可治疗低血压,然而可以观察到存在过度缩血管反应,因为- 2受体激动剂导致压力感受器反射[ 7 ]和- 1肾上腺素受体介导的血管收缩作用增强[ 8 ] 。