Evidence that action potential generation is not the exclusive determinant to trigger spontaneous myogenic contraction of guinea-pig urinary bladder smooth muscle

2002 ◽  
Vol 176 (1) ◽  
pp. 57-63 ◽  
Author(s):  
T. Imai ◽  
Y. Tanaka ◽  
T. Okamoto ◽  
Y. Yamamoto ◽  
T. Horinouchi ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Guinea Pig ◽  
Action Potential ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Bladder Smooth Muscle ◽  
Urinary Bladder Smooth Muscle

Properties of a tonically active, sodium-permeable current in mouse urinary bladder smooth muscle

2004 ◽  
Vol 286 (6) ◽  
pp. C1246-C1257 ◽  
Author(s):  
Kevin S. Thorneloe ◽  
Mark T. Nelson
Keyword(s):  
Membrane Potential ◽  
Urinary Bladder ◽  
Action Potential ◽  
Action Potentials ◽  
Resting Membrane Potential ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Bladder Smooth Muscle ◽  
Voltage Dependent ◽  
Urinary Bladder Smooth Muscle

Urinary bladder smooth muscle (UBSM) elicits depolarizing action potentials, which underlie contractile events of the urinary bladder. The resting membrane potential of UBSM is approximately −40 mV and is critical for action potential generation, with hyperpolarization reducing action potential frequency. We hypothesized that a tonic, depolarizing conductance was present in UBSM, functioning to maintain the membrane potential significantly positive to the equilibrium potential for K+ ( EK; −85 mV) and thereby facilitate action potentials. Under conditions eliminating the contribution of K+ and voltage-dependent Ca2+ channels, and with a clear separation of cation- and Cl−-selective conductances, we identified a novel background conductance ( Icat) in mouse UBSM cells. Icat was mediated predominantly by the influx of Na+, although a small inward Ca2+ current was detectable with Ca2+ as the sole cation in the bathing solution. Extracellular Ca2+, Mg2+, and Gd3+ blocked Icat in a voltage-dependent manner, with Ki values at −40 mV of 115, 133, and 1.3 μM, respectively. Although UBSM Icat is extensively blocked by physiological extracellular Ca2+ and Mg2+, a tonic, depolarizing Icat was detected at −40 mV. In addition, inhibition of Icat demonstrated a hyperpolarization of the UBSM membrane potential and decreased the amplitude of phasic contractions of isolated UBSM strips. We suggest that Icat contributes tonically to the depolarization of the UBSM resting membrane potential, facilitating action potential generation and thereby a maintenance of urinary bladder tone.

Functional Characterization of Adenosine Receptors and Coupling to ATP-Sensitive K+ Channels in Guinea Pig Urinary Bladder Smooth Muscle

2002 ◽  
Vol 300 (3) ◽  
pp. 910-917 ◽  
Author(s):  
Sujatha M. Gopalakrishnan ◽  
Steven A. Buckner ◽  
Ivan Milicic ◽  
Duncan R. Groebe ◽  
Kristi L. Whiteaker ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Guinea Pig ◽  
Adenosine Receptors ◽  
Functional Characterization ◽  
Bladder Smooth Muscle ◽  
K Channels ◽  
Urinary Bladder Smooth Muscle

scholarly journals Phospholipase C Inhibitors Suppress Spontaneous Mechanical Activity of Guinea Pig Urinary Bladder Smooth Muscle

2003 ◽  
Vol 26 (8) ◽  
pp. 1192-1194 ◽  
Author(s):  
Yoshio Tanaka ◽  
Takao Okamoto ◽  
Toshiyasu Imai ◽  
Takahiro Horinouchi ◽  
Hikaru Tanaka ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Guinea Pig ◽  
Phospholipase C ◽  
Mechanical Activity ◽  
Bladder Smooth Muscle ◽  
Urinary Bladder Smooth Muscle

Effect of Cromakalim and Pinacidil on 86Rb Efflux from Guinea Pig Urinary Bladder Smooth Muscle

Pharmacology ◽  
1994 ◽  
Vol 49 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Shephali Trivedi ◽  
S. Stetz ◽  
J Leviri ◽  
L. Li ◽  
S. Kau
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Guinea Pig ◽  
Bladder Smooth Muscle ◽  
Urinary Bladder Smooth Muscle

Inhibitory Effects of Antidepressants on Acetylcholine-Induced Contractions in Isolated Guinea Pig Urinary Bladder Smooth Muscle

Pharmacology ◽  
2016 ◽  
Vol 99 (1-2) ◽  
pp. 89-98 ◽  
Author(s):  
Junji Uno ◽  
Keisuke Obara ◽  
Hiroko Suzuki ◽  
Satomi Miyatani ◽  
Daisuke Chino ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Guinea Pig ◽  
Bladder Smooth Muscle ◽  
Inhibitory Effects ◽  
Urinary Bladder Smooth Muscle
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