[Ultrastructure of the apical plasma membrane of the granular cells in the frog bladder during cobalt-ion decrease in the vasopressin effect].
Simultaneous studies were performed on changes in water permeability and on the ultrastructural organization of the frog urinary bladder epithelium in the presence of Co-ions under vasopressin-stimulated water flow. A possible inhibition of the vasopressin-stimulated water flows by Co-ions is supposed from the extracellular surface of the apical membrane of granular cells responsible for water permeability of this epithelium. Using the freeze-fracture technique for studying the apical membrane ultrastructure, it was shown that with the maximum water flow the square occupied by intramembrane particle aggregates was as much as 1.8% of the total square of membranes, to reduce to 0.3% with the smaller water flow, the average sizes of aggregates being 0.35 mkm and 0.08 mkm in both these cases, respectively. Application of 1 x 10(-3)-1 x 10(-4) M CoCl2 from the mucose part inhibits the vasopressin-stimulated water flow. In this case no aggregates are actually seen on the P-face of the apical membrane, the number of intramembrane particles of the E-face being similar to that when the water permeability was originally low. It is concluded that Co-ion may influence the structure and function of the apical plasma membrane from its extracellular surface.
Komissarchik
Ia Iu
IaIu
Romanov
V I
VI
Snigirevskaia
E S
ES
Shakhmatova
E I
EI
Natochin
Iu V
IuV
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure; D002463:Cell Membrane Permeability / Q000187:drug effects; D003035:Cobalt / Q000494:pharmacology*; D004347:Drug Interactions; D005614:Freeze Fracturing; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D011896:Rana temporaria; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000648:ultrastructure; D017483:Receptors, Vasopressin; D001743:Urinary Bladder / Q000187:drug effects / Q000648:ultrastructure*; D014667:Vasopressins / Q000494:pharmacology*
D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014667:Vasopressins; D003035:Cobalt
Ul'trastruktura apikal'noĭ plazmaticheskoĭ membrany granuliarnykh kletok mochevogo puzyria liagushki pri snizhenii éffekta vazopressina ionami kobal'ta.