We investigated the effects of
Evodiae Fructus and synephrine, one of the components of
Evodiae Fructus, on blood vessels. We found that
Evodiae Fructus (1 × 10
−6 – 3 × 10
−4 g/mL) had constrictive effects on rat aorta. The vasoconstrictive effects of
Evodiae Fructus were significantly inhibited by pretreatment with prazosin (adrenergic α
1-receptor antagonist), BRL15572 [5-hydroxytryptamine (5-HT)
1D antagonist], and ketanserin (5-HT
2A antagonist), but its vasoconstrictive effects were not inhibited by pretreatment with SB216641 (5-HT
1B antagonist) or propranolol (adrenergic β-receptor antagonist). These results suggest that
Evodiae Fructus constricts rat aorta via adrenergic and serotonergic receptors. We also investigated the constrictive effects of synephrine on blood vessels. The vasoconstrictive effects of synephrine (1 × 10
−7 – 3 × 10
−5 mol/L) were significantly inhibited by pretreatment with prazosin, BRL15572, and ketanserin. However, its constrictive effects were not inhibited by pretreatment with SB216641 and propranolol. The pA
2 values of prazosin or ketanserin were nearly equal between
Evodiae Fructus and synephrine. Because the constrictive effects of both
Evodiae Fructus and synephrine were exerted via adrenergic α
1-receptors and serotonergic (5-HT
1D and 5-HT
2A) receptors, synephrine may be one of the important components in the constrictive effects of
Evodiae Fructus.
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