Cyclic AMP increases electrical capacitance of apical membrane of toad urinary bladder.
We have measured the effects of oxytocin and three other compounds (chlorophenyl-thio-cyclic AMP, forskolin and theophylline) that increase cytoplasmic cyclic AMP on the impedance of the toad urinary bladder. Membrane capacitance was calculated from transepithelial impedance measured by a computerized sine wave method. All four agents increased tissue capacitance. Since in these tissues this parameter is proportional to apical membrane area our results suggest that cAMP can be a second messenger involved in the action of agents that promote fusion of exocytotic vesicles with the apical membrane.
Van Driessche
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Laboratorium voor Fysiologie, KUL, Leuven, Belgium.
Erlij
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D000818:Animals; D002024:Bufo marinus; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D003655:Decerebrate State; D004553:Electric Conductivity / Q000187:drug effects; D008566:Membranes / Q000187:drug effects; D010121:Oxytocin / Q000494:pharmacology*; D013806:Theophylline / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology; D001743:Urinary Bladder / Q000187:drug effects*
D013873:Thionucleotides; D005576:Colforsin; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D010121:Oxytocin; D013806:Theophylline; D000242:Cyclic AMP