title: Effect of extracellular calcium and calcium channel antagonists on ATP and field stimulation induced contractions of the mouse urinary bladder.
abstract: 1. The dependence on extracellular calcium of the response to the electrical stimulation, ATP and high K induced contractions has been studied in the mouse urinary bladder. 2. The responses to ATP, field stimulation and K induced depolarization were eliminated in calcium free EGTA medium. However, a small remanent of these responses was observed in the absence of calcium in the superfusing medium. 3. The calcium antagonists verapamil, nifedipine and diltiazem decreased in a dose dependent manner the contractions induced by ATP and electrical stimulation of the mouse urinary bladder. 4. The responses of the mouse urinary bladder to high K concentration were antagonized by verapamil and diltiazem, but nifedipine was less effective in decreasing the tonic component of the contraction induced by K in the muscle. 5. The responses of the mouse urinary bladder to electrical stimulation, ATP and high concentration of K are mainly dependent on the extracellular calcium.
authors.affiliation: Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas y de Recursos Naturales, Universidad de Concepción, Chile.
authors.forename: C G
authors.initials: CG
authors.lastname: Acevedo
authors.forename: E
authors.initials: E
authors.lastname: Contreras
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004110:Diltiazem / Q000494:pharmacology; D004558:Electric Stimulation; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D001743:Urinary Bladder / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D000255:Adenosine Triphosphate; D014700:Verapamil; D004110:Diltiazem; D009543:Nifedipine; D002118:Calcium