The anti-fertility effects of various extracts of achyranthes bidentata were studied in female mice. It was found that the benzene extract (50 mg/kg, 80mg/kg) administracted orally could show significant anti-fertility, anti-implantation and anti-early-pregnancy effects, and that the chloroform extract (80mg/kg, 120mg/kg) given orally showed effective anti-fertility and anti-early-pregnancy effects on mice, with no significant anti-implantation effect.

The effects of Zn~(2+) on the isolated superior cervical sympathetic ganglion of rabbit were stud ied with sucrese-gap method. It was found thatZn~(2+) significantly inhibited ganglienic action poten-tial with a manner of concentration-dependence.The IC-50 value was 1. 48 mmol/L. The effects ofZn~(2+) were antagonized by neostigmine and 1-cys-tein, reduced under high concentration of Ca~(2+) andenhanced under low concentration of Ca~(2+). It wasalso found that Zn~(2+) inhibited ganglionic N wave,less affected p wave and without any effect on LNwave.

Experiments were carried out on the isolatedrat phrenic nerve diaphragm preparations and chickbiventer cervicis preparations. Zn~(2+) at cumulativeconcentration inhibited muscle contractile responseto indirect stimulation without affecting the con-ductivity of nerve. The inhibiting. action of Zn~(2+) onthe muscle contractile response to indirect stimula-tion was stronger than that on contractile responseto direct stimulation. Zn~(2+) did not affect the Achsensitivity of the chick biventer cervicis muscleThe effects of Zn~(2+) on neuromuscular transmis-sion were antagonized by Ca~(2+) and L-cystein.

The effect of Sin on the transmission of the impulses through isolated rabbit superior cervical sympathetic ganglia in comparison with that of curare by the sucrose - gap method was studied.Inhibi -tory effect of Sin on the action potential was dose-dependent but no effect on the excitability and conductivity of preganglionic nerves. The ID50 of Sin and curare were 1.2 mM and 0.2 mM, respectively. The effect of Sin was reduced in high Ca2+ concentration solution, and enhanced under Ca2+ free solution. Neostigmine antagonized the effect of Sin.

The effects of Cu2+ on superior cervical sympathetic ganglion of rabbits were studied by the sucrose-gap method. Cu2+ at cumula- tive concentration inhibited ganglion action potentials. IC50 of Cu2+ was 0.26 mmol/L. The effects of Cu2+ were antagonized by neostig-miae and L-cystein, while enhanced under 1/2[Ca2+] and reduced under 3[Ca2+] .Cu2+ inhibited ganglionic N wave and P wave,without affecting LN wave.

0.25mg/ml of Achyranthes bidentata Saponins( ABS ) in De Jalon's solution usually caused an obvious excitant action in both virgin and pregnant uterine preparations. The uterine excitation was blocked effectively by prior treatment of the preparations with 20?g/ml of indomethacin for 1 h.In the isolated uterine preparations taken from the rats treated with indomethacin, 15 mg/rat orally twice a day for 2 and a half days, the excitant action of ABS was obviously reduced.Treatment of the uterine segments with 0.5?g/ml of chlorpromazine for half an hour also blocked the excitant response. However, treatment of the uterine preparations with 10?g/ml of atropine for 10 min had no abvious effect on the excitant response. The probable mecha-nism of action of ABS was discussed.

On the isolated rat phrenic nerve-diaphragm preparation Sin blocked the neuromuscular transmission without affecting the excitability & conductivity of phrenic nerve. Inhibitory effect of Sin on indirect contraction of diaphragm was dose-dependent, increasing with increasing dose & was antagonized by high Ca2+ solution. When the transmission was blocked by Sin, the ACh sensitivity of the chick biventer cervicis muscle was reduced. Like succinylcholine Sin induced the contractile response of the toade rectus abdominis. Neostigmine did not antagonize, but enhanced the blocking effect of neuromuscular transmission of Sin. These results indicate that Sin has some characteristics of depolarizing muscular relaxants.

Effects of Cu2+,Zn2+and Mn2+ on responses to ACh were studied with toad rec-tus abdominis. Cu2+, Zn2+and Mn2+concentra-tion- dependently shifted the concentration-response curves for ACh to the right unparallelly and reduced the maximal response considerably. The pAh values of Cu2+ , Zn2+ and Mn2+ were 3.69, 2.95 and 2. 62, respectively. The inhibitory potent of Cu2+ and Zn2+ seemed to be 11.7 times and 2. 1 times respectively more thanthat of Mn2+. It was suggested that Cu2+, Zn2+ and Mn2+postsynaptically interfere with the action of ACh. However, Zn2+in lower concentration shifted the bottom section of the curve for ACh to the left and top, and shifted the top section of the curve to the right, suggesting that Mn2+in lower concentration be possessed of partial agonistic property.