Changes in intracellular pH close to term and their possible significance to labour.
The contractile pattern of uterine smooth muscle is markedly altered by even modest manipulations of intracellular pH (pHi); an acidification can abolish contractions, while alkalinization increases contractility. As at the end of gestation the uterus changes from being relatively quiescent to highly contractile, we investigated whether pHi changes with pregnancy in women. Isolated tissue was loaded with the pH-sensitive fluorophore, carboxy-SNARF. We found a significant alkalinization over the last few weeks of pregnancy. Such an increase in pHi will increase contractility of the uterus, and may therefore contribute to the mechanisms ensuring strong and efficient contractions occur during labour.
Parratt
J R
JR
The Physiological Laboratory, The University of Liverpool, PO Box 147, Liverpool L69 3BX, UK.
Taggart
M J
MJ
Wray
S
S
D000328:Adult; D001578:Benzopyrans; D036861:Delivery, Obstetric; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000378:metabolism*; D007743:Labor, Obstetric; D009215:Myometrium / Q000378:metabolism*; D009284:Naphthols; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012235:Rhodamines; D014590:Uterine Contraction / Q000502:physiology
D001578:Benzopyrans; D005456:Fluorescent Dyes; D009284:Naphthols; D012235:Rhodamines; C068301:carboxy-seminaphthorhodaminefluoride