Stretch-activated nonselective cation channels in urinary bladder myocytes: importance for pacemaker potentials and myogenic response.
Filling of the bladder with urine stretches the myocytes in the wall. Stretch activates nonselective cation channels (SACs) thereby constituting a pacemaking mechanism. Once action potentials are triggered, Ca2+ influx through nifedipine-sensitive Ca2+ channels provides activator Ca2+ for the stretch-induced increase in wall tension (myogenic response). An additional component of myogenic response is independent of nifedipine and membrane potential; Ca2+ influx through SACs is large enough to induce Ca2+ release from intracellular stores.
Wellner
M C
MC
Department of Physiology, University of Cologne, Köln, FRG.
Isenberg
G
G
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002412:Cations / Q000378:metabolism / Q000494:pharmacology; D005682:Gadolinium / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects; D007473:Ion Channels / Q000502:physiology*; D008274:Magnesium / Q000494:pharmacology; D009130:Muscle, Smooth / Q000502:physiology*; D009543:Nifedipine / Q000494:pharmacology; D013314:Stress, Mechanical; D001743:Urinary Bladder / Q000502:physiology*
D015220:Calcium Channels; D002412:Cations; D007473:Ion Channels; D005682:Gadolinium; D008274:Magnesium; D009543:Nifedipine; D002118:Calcium