Related Experiment Video
Updated: Jul 31, 2026

Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology
Published on: August 18, 2014
[Ultrastructure and elemental composition of frog bladder granular epithelial cells in normal state and upon
A N Gorshkov1, E V Korolev, Ia Iu Komissarchik
1Institute of Cytology RAS, St. Petersburg. angorsh@mail.cytspb.rssi.ru
Abstract:
Changes in the frog urinary bladder granular cell ultrastructure were analysed in parallel with those in element composition of these cells after induction of water transport across the urinary bladder wall. Two ultrastructural (ultrathin section and freeze-fracture) methods were used in addition to two methods of object preparation for electron microprobe analysis--freeze-drying and freeze-substitution. It has been shown that arginin-vasotocin stimulation of osmotic water flow across the urinary bladder wall causes certain morphological changes in the granular cells: decrease in electron density of the cytoplasm, depolymerization of the apical submembrane layer of actin microfilaments, increase in the number of sites of specific granules and apical membrane fusion, emergency of intramembrane particle aggregates in the apical membrane P-face. The quantitative electron microprobe analysis made it possible to reveal a statistically significant increase in sodium and calcium concentration and fall in that of potassium and chlorine in granular cells after water transport stimulation. A concentration gradient of sodium and potassium ions was seen to appear along the apical-basal axis in the cytoplasm of granular cells. Possible association between the obvious morphological transformations in granular cells and changes in their elemental composition has been discussed, in addition to some regulatory significance of calcium concentration increase in granular cells after arginin-vasotocin-induced osmotic water transport.
More Related Videos
Related Concept Videos
Transcellular Transport of Solutes
Reabsorption and Secretion in the DCT and Collecting Duct
The distal part of the DCT, along with the...
Formation of Concentrated Urine
Urinary Bladder
In males, the bladder is situated in front of the rectum, while in females, it is positioned anterior to the vagina and uterus. The bladder floor contains an inverted triangular area called the trigone, defined by the two ureteric...
Anatomy of the Genitourinary System II: Bladder and Urethra
Physiology of the Genitourinary System III: Urine Concentration and Dilution

