The Sound of Evolution
Pseudoephedrine
偽麻黃鹼
Mechanism of action:
Pseudoephedrine 是一種間接型與直接型混合的 α₁-腎上腺素受體促效劑（mixed-acting α₁-adrenergic agonist）。Pseudoephedrine 可直接刺激鼻腔與上呼吸道黏膜血管平滑肌上的 α₁-腎上腺素受體，透過 Gq 蛋白偶聯，活化磷脂酶 Cβ（phospholipase Cβ），提升 IP₃/DAG，使細胞質鈣離子上升與活化蛋白激酶 C（protein kinase C），導致血管收縮、減少黏膜血流與組織水腫。Pseudoephedrine 亦可進入交感神經末梢，促使儲存於囊泡中的正腎上腺素（norepinephrine）釋放，進一步增強 α₁-受體介導的血管收縮作用。
Reference(s):
1. Aviado DM Jr et al. (1958). Cardiovascular effects of sympathomimetic bronchodilators; epinephrine, ephedrine, pseudoephedrine, isoproterenol, methoxyphenamine and isoprophenamine. J Pharmacol Exp Ther.
2. Chen K et al. (1930). Ephedrine and Related Substances. Medicine.
3. Volpp M et al. (2019). Determination of plasma protein binding for sympathomimetic drugs by means of ultrafiltration. Eur J Pharm Sci.