AIM To investigate the effects of carbachol on the
intracellular free calcium concentration (
2+ > i) and
the formation of inositol 1,4,
5 triphosphate (IP 3) in the cervix myometrium cells
(CMC) of human and to probe into the relationship between the
i increase and the IP
3 formation induced by muscarinic receptor agonist carbachol. METHODS Spectroflurometry
and radioimmunoassay were used to examine the i levels, and IP 3 levels
respectively. RESULTS In the basic condition the i of CMC was (178±21) nmol·L
-1 . The i induced by 1, 10 and 100 μmol·L -1 CCh was (244±31), (326±39)
and (437±61) nmol·L -1 respectively, which showed the dose dependent relationship. In
the calcium free medium, the i levels induced by CCh decreased. 10 μmol·L -1
atropine (Atr) blocked the effects of CCh on the i . In basic condition the IP 3 levels of
CMC was (81 5±8 6) nmol·g -1 protein. The IP 3 levels was increased by 1,10, 100 μ
mol·L -1 CCh and reached the peak at the 5 min after incubation in CCh. The peak of the IP
3 levels were (107±15), (135±31) and (148±29) nmol·g -1 proein respectively. 10 μ
mol·L -1 Atr obviously inhibited CCh induced IP 3 formation. CONCLUSION CCh dose
dependently increased the levels of i and the IP 3 formation in CMC by activating
muscarinic receptor. The results suggested that IP 3 induced calcium release was an
important regulatory mechanism in CCh induced i increase in CMC.