Abstract
1. We measured the differences in electrical potential between mother and fetus in the guinea-pig. The fetus was 33 +/- 2 (S.E. of mean) mV negative with respect to the mother. 2. Salts of bromine, sulphate, rubidium, and lithium were injected into pregnant sows and blood samples were obtained from the sows and their fetuses at various times after injection. The transplacental electrical potentials at which each of these ions would be in electrochemical equilibrium across the placental exchange barrier were calculated from the Nernst equation and the concentrations in maternal and fetal plasmas. 3. The differences in transplacental electrical potential calculated from the steady-state concentrations of these ions in maternal and fetal plasmas were within 1 mV of zero. 4. These observations are consistent with a very small difference in electrical potential across the placental exchange barrier itself, and the generation of a potential difference between mother and fetus at a site other than the exchange barrier.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- ALEXANDER D. P., NIXON D. A., WIDDAS W. F., WOHLZOGEN F. X. Gestational variations in the composition of the foetal fluids and foetal urine in the sheep. J Physiol. 1958 Jan 23;140(1):1–13. doi: 10.1113/jphysiol.1958.sp005911. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Armentrout T., Katz S., Thornburg K. L., Faber J. J. Osmotic flow through the placental barrier of chronically prepared sheep. Am J Physiol. 1977 Oct;233(4):H466–H474. doi: 10.1152/ajpheart.1977.233.4.H466. [DOI] [PubMed] [Google Scholar]
- KAISER I. H., CUMMINGS J. N. Plasma electrolytes of the pregnant ewe and fetal lamb. Am J Physiol. 1958 Jun;193(3):627–633. doi: 10.1152/ajplegacy.1958.193.3.627. [DOI] [PubMed] [Google Scholar]
- Mellor D. J., Cockburn F., Lees M. M., Blagden A. Distribution of ions and electrical potential differences between mother and fetus in the human at term. J Obstet Gynaecol Br Commonw. 1969 Nov;76(11):993–998. doi: 10.1111/j.1471-0528.1969.tb09465.x. [DOI] [PubMed] [Google Scholar]
- Mellor D. J. Distribution of ions and electrical potential differences between mother and foetus at different gestational ages in goats and sheep. J Physiol. 1970 Mar;207(1):133–150. doi: 10.1113/jphysiol.1970.sp009053. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mellor D. J. Potential differences between mother and foetus at different gestational ages in the rat, rabbit and guinea-pig. J Physiol. 1969 Oct;204(2):395–405. doi: 10.1113/jphysiol.1969.sp008919. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meschia G., Wolkoff A. S., Barron D. H. DIFFERENCE IN ELECTRIC POTENTIAL ACROSS THE PLACENTA OF GOATS. Proc Natl Acad Sci U S A. 1958 May;44(5):483–485. doi: 10.1073/pnas.44.5.483. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stulc J. J., Rietveld W. J., Soeteman D. W., Versprille A. The transplacental potential difference in guinea-pigs. Biol Neonate. 1972;21(1):130–147. doi: 10.1159/000240503. [DOI] [PubMed] [Google Scholar]
- Wright G. H. The potential difference between amniotic fluid and maternal extracellular fluid in the rabbit. Biol Neonat. 1966;10(3):193–199. doi: 10.1159/000240028. [DOI] [PubMed] [Google Scholar]