In vitro determination of the mechanism of the uterine stimulatory effect of Newbouldia laevis

Figures & data

Table 1.  Effect of antagonists on the EC₅₀ of EEN.

Drugs	EC50 (mg/mL)
EEN alone	3.01 × 10^−4 ± 0.05
EEN + PHEN (4.09 nM)	3.05 × 10^−4 ± 0.08
EEN + PHEN (40.91 nM)	3.05 × 10^−4 ± 0.06
EEN + DPH (4.45 nM)	6.15 × 10^−4 ± 0.18^a
EEN + DPH (44.47 nM)	11.56 × 10^−4 ± 0.14^a
EEN + ATR (1.18 nM )	10.46 × 10^−4 ± 0.17^b
EEN + ATR (11.91 nM)	46.12 × 10^−4 ± 0.07^b
EEN + VER (2.03 nM)	9.76 × 10^−4 ± 0.09^a
EEN + VER (20.35nM)	21.43 × 10^−4 ± 0.11^b

^ap <0.05;^bp <0.01; n = 6 rats per group.

Table 2.  Effect of antagonists on the EC₅₀ of oxytocin.

Drugs	EC50 (nM)
OT alone	5.25 ± 0.05
OT + PHEN (4.09 nM)	5.19 ± 0.08
OT + PHEN (40.91 nM)	5.31 ± 0.13
OT + DPH (4.45 nM)	5.22 ± 0.18
OT + DPH (44.47 nM)	5.27 ± 0.11
OT + ATR (1.18 nM )	5.19 ± 0.11
OT + ATR (11.91 nM)	5. 21 ± 0.09
OT + VER (2.03 nM)	15.15 ± 0.12^a
OT + VER (20.35 nM)	30.98 ± 0.16^a

^ap <0.01; n = 6 rats per group.

Figure 1.  Concentration-response curves showing the uterine contractile response of the ethanol extract of N. laevis (EEN) in the absence and presence of phentolamine (PHEN). There was no significant difference in the E_max of EEN (n = 6 rats).

Figure 2.  Concentration-response curves showing the contractile response of oxytocin in the presence and absence of phentolamine (PHEN). There was no significant difference in the E_max of oxytocin (n = 6 rats).

Figure 3.  Concentration-response curves of the effect of diphenhydramine (DPH) on the ethanol extract of N. laevis. DPH inhibited the effect of the extract but there was no significant difference in the E_max of EEN (n = 6 rats).

Figure 4.  Concentration-response curves of the effect of diphenhydramine (DPH) on oxytocin-induced uterine contraction. No inhibition was observed and there was no significant difference in the E_max of oxytocin (n = 6 rats).

Figure 5.  Concentration-response curves showing uterine response to EEN in the presence and absence of atropine (ATR). ATR inhibited the effect of the extract but there was no significant difference in the E_max (n = 6 rats).

Figure 6.  Concentration-response curves of oxytocin-induced uterine contraction in the presence of atropine (ATR). No inhibition was observed (n = 6 rats).

Figure 7.  Concentration-response curves of EEN in the presence of verapamil (VER). VER shifted the curve to the right and significantly depressed (p <0.01) the E_max (n = 6 rats).

Figure 8.  Concentration-response curves of oxytocin alone and in the presence of verapamil (VER). VER significantly depressed (p <0.01) the E_max and shifted the curve to the right (n = 6 rats).