title: Site of catecholamine modulation of feto-maternal electric potential difference in the pig.
abstract: Feto-maternal vascular (PD(F-M)) and amniotic maternal (PD(A-M)) potential differences were measured simultaneously on seven occasions in six conscious pigs of 100-106 days gestation. Resting values of PD(F-M) and PD(A-M) were not significantly different although the range was wide. Fetal intravascular injection of 20 microg adrenaline, but not of saline, was associated with a prompt reversible change, of equal magnitude, in both PD(F-M) and PD(A-M). In some experiments polarity was reversed. Feto-amniotic potential difference did not change. There was no change in fetal plasma K+ and Na+ concentrations. Because of the simultaneous and equal alterations in PD(F-M) and PD(A-M) following adrenaline and the anatomical configuration of the pig conceptus, we conclude that the catecholamine modifiable component of PD(F-M) is generated by electrogenesis in the pig placenta, probably by its chorionic (trophoblastic) cell layer.
authors.affiliation: Department of Child Health, University of Manchester, St Mary's Hospital, UK.
authors.forename: B S
authors.initials: BS
authors.lastname: Ward
authors.forename: J D
authors.initials: JD
authors.lastname: Glazier
authors.forename: C P
authors.initials: CP
authors.lastname: Sibley
authors.forename: R D
authors.initials: RD
authors.lastname: Boyd
mesh_terms: D000818:Animals; D004594:Electrophysiology; D004837:Epinephrine / Q000494:pharmacology*; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005333:Fetus / Q000502:physiology*; D007267:Injections; D009994:Osmolar Concentration; D011188:Potassium / Q000097:blood; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D012964:Sodium / Q000097:blood; D012965:Sodium Chloride / Q000494:pharmacology; D013552:Swine
chemical_list: D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium; D004837:Epinephrine