Effects of (-)-stepholidine and tetrahydroberberine on high potassium-evoked contraction and calcium influx in rat artery.
The relaxant effects of (-)-stepholidine ((-)-SPD) and tetrahydroberberine (THB) on rat aorta were studied in vitro. (-)-SPD IC50 18.1 (95% confidence limits 11.1-29.5) mumol.L-1 and THB IC50 18.6 (95% confidence limits 9.2-37.9) mumol.L-1 inhibited the contractions caused by KCl (100 mmol.L-1) concentration-dependently. Both (-)-SPD and THB markedly inhibited the 160 mmol.L-1 KCl-stimulated 45Ca influx. The inhibitions by (-)-SPD 10 mumol.L-1 and 100 mumol.L-1 were 18 +/- 13% (P > 0.05) and 47.0 +/- 2.8% (P < 0.01), respectively. The inhibitions by THB 10 mumol.L-1 and 100 mumol.L-1 were 36 +/- 9% (P < 0.01) and 43 +/- 8% (P < 0.05), respectively. The results showed that the effective concentrations of the 2 drugs inhibiting high KCl-induced contraction and 45Ca transmembrane influx in rat thoracic aorta were at a similar level, and that they were nearly 1/100 and 1/10 of those of verapamil respectively, indicating that (-)-SPD and THB had similar calcium channel blocking effect on rat artery, but were weaker than verapamil.
Yang
S
S
Department of Pharmacology, School of Pharmacy, Shanghai Medical University, China.
Miao
Y S
YS
Han
Q
Q
Jiang
M H
MH
Jin
G Z
GZ
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D001599:Berberine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D000252:Calcium-Transporting ATPases / Q000187:drug effects*; D018492:Dopamine Antagonists; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D018492:Dopamine Antagonists; D001599:Berberine; C010513:stepholidine; D014700:Verapamil; D000252:Calcium-Transporting ATPases; C004645:canadine