下列那一種兒茶酚類物質,不必經過胞泌(Exocytosis)作用直接可由細胞漿穿過細胞膜釋放至兒茶酚胺(Catecholamine)神經末梢外?
Dopamine
Norepinephrine
Epinephrine
3,4-Dihydroxyphenyl acetic acid (DOPAC)