Maternofetal electrical potential difference in conscious sheep: effect of fetal death or acidosis.
Maternofetal electrical potential difference (pd) was measured in conscious pregnant ewes during the last 40 days of gestation. Recordings were made via catheters filled with saline solution and chronically implanted in at least two blood vessels on either side of the placenta. The pd ranged between -14 and 93 mV, mother positive. The mean potential declined from 54 +/- 8 mV (n = 5) immediately after operation to 28 +/- 7 mV after 48 hours and did not alter significantly thereafter. The pd increased with fetal acidosis induced by infusion of acid. The mean slope was 54 +/- 11 mV per pH unit (n = eight infusions). The pd rose when the fetus died, but was abolished by killing the ewe. The pd 1 day postoperatively fell with increasing gestational age (pd = 164 - 1.00 x days; p < 0.05, n = 41 sheep).
D000482:Allantois / Q000502:physiology; D000650:Amnion / Q000502:physiology; D000818:Animals; D004553:Electric Conductivity; D005260:Female; D005313:Fetal Death / Q000503:physiopathology; D005333:Fetus / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011270:Pregnancy, Animal; D012756:Sheep / Q000502:physiology*