ISSN:
1432-136X
Keywords:
Porcine placenta
;
Sodium transport
;
Short circuit current
;
Pregnancy
;
Histology
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary 1. The electrolyte transport capacities of the porcine placenta and fetal membranes (amnion, chorion, and allantois) during gestation (47–112 days) were assessed in vitro and in the absence of electrochemical, osmotic, or hydrostatic driving forces. Net transmural transport of 22Na and 36Cl across sections of porcine allantochorion-endometrium (ALCE), amniochorionendometrium (AMCE), and allantoamnion (AA) mounted in Ussing chambers could not be detected at any stage of gestation. 2. These tissues were characterised throughout gestation by low electrical potential difference (PD; 〈5 mV, fetal side positive with respect to maternal side) and short circuit current (SCC; 〈16 μA · cm-1) which were amiloride and iodoacetate sensitive. 3. A periparturitent reversal in the polarity of PD to fetal side negative and a change in the direction of the SCC was observed in tissues obtained from sows (n=3) at 111–112 day gestation. These changes were accompanied by a 73% increase in electrical resistance (R) and a 2–10-fold decrease in the permeability of tissues to Na and Cl. 4. Morphological studies revealed a decrease in the thickness of allantoamnion and a decrease in the height of epithelia from ALCE, AMCE, and AA during gestation, indicating a decrease in activity. These morphological changes only partly explained the pre-term electrophysiological changes in these tissues.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00262883
Permalink
