Action of progesterone on contractile activity of isolated gastric strips in rats

Table 1 Effect of progesterone on the resting tension of gastric smooth muscle in rats

Progesterone µmol·L-1	Resting tension/g
	Fundus	Body		Antrum		Pylorus
	LM	LM	CM	LM	CM	CM
5	-0.08 ± 0.12a	-0.008 ± 0.08	0	0.01 ± 0.05	0	0
10	-0.08 ± 0.08b	-0.05 ± 0.11	-0.03 ± 0.06	0.04 ± 0.09	0	0
50	-0.09 ± 0.06d	-0.12 ± 2.0a	0.01 ± 0.15	0.02 ± 0.04	0	-0.03 ± 0.10

The values were expressed as differences in resting tension between 3 min before and after the addition of progesterone (5, 10 and 50 µmol·L^-1) (The same in Tab 2). The resting tension of each strip in control (progesterone 0 µmol·L^-1) was 1. LM: Longitudinal muscle; CM: Circular muscle. x^-± s, n = 12,

^aP < 0.05,

^bP < 0.01,

^dP < 0.001, vs control by paired t test.

Table 2 Effect of progesterone on the mean contractile amplitude of body and antrum, and the motility index of pylorus in rats

Progesterone µmol·L-1		Contractile amplitude/mm				Motility index/cm.s-1
		Body		Antrum		Pylorus
		LM	CM	LM	CM	CM
5	B	13.4 ± 17.0	12.0 ± 13.2	13.6 ± 8.6	14.1 ± 15.0	92.4 ± 16.2
	C	0.2 ± 0.4	-0.9 ± 3.0	-0.5 ± 0.8a	-0.8 ± 1.7	1.7 ± 4.8
10	B	12.8 ± 17.6	11.2 ± 14.0	14.0 ± 7.1	13.6 ± 12.9	98.5 ± 20.0
	C	-2.1 ± 3.8a	-1.5 ± 1.6b	-1.8 ± 2.0b	-3.1 ± 1.8d	-22.5 ± 16.6d
50	B	12.0 ± 16.9	11.8 ± 12.9	12.6 ± 8.0	12.6 ± 14.8	110.2 ± 22.8
	C	-7.5 ± 5.5a	-5.6 ± 3.0d	-5.4 ± 3.8d	-5.8 ± 3.8d	-47.4 ± 31.2d

B: Basic values in 3 min before addition of progesterone; C: Changes in 3 min after addition of progesterone (The same in Tab 3). x^-± s, n = 12.

^aP < 0.05,

^bP < 0.01,

^dP < 0.001, vs corresponding B by paired t test.

Table 3 Effect of progesterone on the mean contractile amplitude of body after indomethacin or phentolamine pretreatment in rats

Gastric body muscle	Contractile amplitude/mm
	Pr		I + Pr				Ph + Pr
	B	C	B	C	B	C	B	C	B	C
LM	12.0 ± 16.9	-7.5 ± 5.5b	12.9 ± 17.1	-0.1 ± 6.0	12.5 ± 18.4	-8.2 ± 6.9b	12.1 ± 19.2	1.4 ± 3.8	15.4 ± 16.5	-5.2 ± 4.5d
CM	11.8 ± 12.9	-5.6 ± 3.0b	12.2 ± 14.0	1.2 ± 5.2	12.6 ± 13.2	-3.5 ± 2.5d	11.7 ± 12.6	0.2 ± 0.5	11.4 ± 13.0	-3.6 ± 2.7d

Phentolamine (1 µmol·L^-1) or indomethacin (10 µmol·L^-1) was added 3 min before the addition of progesterone (50 µmol·L^-1). x^-± s, n = 12. Pr: Progesterone, I: Indomethacin, Ph: Phentolamine.

^bP < 0.001 vs corresponding B by paired t test;

^dP < 0.01 vs Pr alone by two samples mean t test.