Inhibitory mechanism of BRL37344 on muscarinic receptor-mediated contractions of the rat urinary bladder smooth muscle

2002 ◽  
Vol 366 (3) ◽  
pp. 198-203 ◽  
Author(s):  
Yuko Kubota ◽  
Tsutomu Nakahara ◽  
Motonari Yunoki ◽  
Akiko Mitani ◽  
Takeshi Maruko ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Muscarinic Receptor ◽  
Inhibitory Mechanism ◽  
Bladder Smooth Muscle ◽  
Rat Urinary Bladder ◽  
Urinary Bladder Smooth Muscle

scholarly journals Expression and functional role of Rho-kinase in rat urinary bladder smooth muscle

2003 ◽  
Vol 138 (5) ◽  
pp. 757-766 ◽  
Author(s):  
Alexandra Wibberley ◽  
Zunxuan Chen ◽  
Erding Hu ◽  
J Paul Hieble ◽  
Timothy D Westfall
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Functional Role ◽  
Rho Kinase ◽  
Bladder Smooth Muscle ◽  
Rat Urinary Bladder ◽  
Urinary Bladder Smooth Muscle

scholarly journals Voltage-gated K+ channels sensitive to stromatoxin-1 regulate myogenic and neurogenic contractions of rat urinary bladder smooth muscle

2010 ◽  
Vol 299 (1) ◽  
pp. R177-R184 ◽  
Author(s):  
Muyan Chen ◽  
Whitney F. Kellett ◽  
Georgi V. Petkov
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Electrical Field Stimulation ◽  
Resting Membrane Potential ◽  
Bladder Smooth Muscle ◽  
Membrane Excitability ◽  
Molecular Fingerprints ◽  
Rat Urinary Bladder ◽  
Voltage Gated ◽  
Urinary Bladder Smooth Muscle

Members of the voltage-gated K+ (KV) channel family are suggested to control the resting membrane potential and the repolarization phase of the action potential in urinary bladder smooth muscle (UBSM). Recent studies report that stromatoxin-1, a peptide isolated from tarantulas, selectively inhibits KV2.1, KV2.2, KV4.2, and KV2.1/9.3 channels. The objective of this study was to investigate whether KV channels sensitive to stromatoxin-1 participate in the regulation of rat UBSM contractility and to identify their molecular fingerprints. Stromatoxin-1 (100 nM) increased the spontaneous phasic contraction amplitude, muscle force, and tone in isolated UBSM strips. However, stromatoxin-1 (100 nM) had no effect on the UBSM contractions induced by depolarizing agents such as KCl (20 mM) or carbachol (1 μM). This indicates that, under conditions of sustained membrane depolarization, the KV channels sensitive to stromatoxin-1 have no further contribution to the membrane excitability and contractility. Stromatoxin-1 (100 nM) increased the amplitude of the electrical field stimulation-induced contractions, suggesting also a role for these channels in neurogenic contractions. RT-PCR experiments on freshly isolated UBSM cells showed mRNA expression of KV2.1, KV2.2, and KV9.3, but not KV4.2 channel subunits. Protein expression of KV2.1 and KV2.2 channels was detected using Western blot and was further confirmed by immunocytochemical detection in freshly isolated UBSM cells. These novel findings indicate that KV2.1 and KV2.2, but not KV4.2, channel subunits are expressed in rat UBSM and play a key role in opposing both myogenic and neurogenic UBSM contractions.

scholarly journals Stimulation of β3-adrenoceptors relaxes rat urinary bladder smooth muscle via activation of the large-conductance Ca2+-activated K+ channels

2008 ◽  
Vol 295 (5) ◽  
pp. C1344-C1353 ◽  
Author(s):  
Kiril L. Hristov ◽  
Xiangli Cui ◽  
Sean M. Brown ◽  
Lei Liu ◽  
Whitney F. Kellett ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Bk Channels ◽  
Bk Channel ◽  
Bladder Smooth Muscle ◽  
Rat Urinary Bladder ◽  
Urinary Bladder Smooth Muscle ◽  
Brl 37344 ◽  
Stimulation Of

We investigated the role of large-conductance Ca2+-activated K+ (BK) channels in β3-adrenoceptor (β3-AR)-induced relaxation in rat urinary bladder smooth muscle (UBSM). BRL 37344, a specific β3-AR agonist, inhibits spontaneous contractions of isolated UBSM strips. SR59230A, a specific β3-AR antagonist, and H89, a PKA inhibitor, reduced the inhibitory effect of BRL 37344. Iberiotoxin, a specific BK channel inhibitor, shifts the BRL 37344 concentration response curves for contraction amplitude, net muscle force, and tone to the right. Freshly dispersed UBSM cells and the perforated mode of the patch-clamp technique were used to determine further the role of β3-AR stimulation by BRL 37344 on BK channel activity. BRL 37344 increased spontaneous, transient, outward BK current (STOC) frequency by 46.0 ± 20.1%. In whole cell mode at a holding potential of Vh = 0 mV, the single BK channel amplitude was 5.17 ± 0.28 pA, whereas in the presence of BRL 37344, it was 5.55 ± 0.41 pA. The BK channel open probability was also unchanged. In the presence of ryanodine and nifedipine, the current-voltage relationship in response to depolarization steps in the presence and absence of BRL 37344 was identical. In current-clamp mode, BRL 37344 caused membrane potential hyperpolarization from −26.1 ± 2.1 mV (control) to −29.0 ± 2.2 mV. The BRL 37344-induced hyperpolarization was eliminated by application of iberiotoxin, tetraethylammonium or ryanodine. The data indicate that stimulation of β3-AR relaxes rat UBSM by increasing the BK channel STOC frequency, which causes membrane hyperpolarization and thus relaxation.

A DIRECT INHIBITORY EFFECT OF ERYTHROMYCIN ON RAT URINARY BLADDER SMOOTH MUSCLE

1999 ◽  
pp. 1006-1009 ◽  
Author(s):  
AVIRAM NISSAN ◽  
NADEER MAUDLEJ ◽  
NAHUM BEGLAIBTER ◽  
YUVAL HASKEL ◽  
HERBERT R. FREUND ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Inhibitory Effect ◽  
Bladder Smooth Muscle ◽  
Rat Urinary Bladder ◽  
Direct Inhibitory Effect ◽  
Urinary Bladder Smooth Muscle

Effects of Vasoactive Intestinal Polypeptide on Isolated Rat Urinary Bladder Smooth Muscle

1992 ◽  
Vol 49 (3) ◽  
pp. 151-153 ◽  
Author(s):  
K. Erol ◽  
G. Ulak ◽  
T. Dönmez ◽  
M.I.I. Cingi ◽  
R.S.S. Alpan ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Vasoactive Intestinal Polypeptide ◽  
Bladder Smooth Muscle ◽  
Rat Urinary Bladder ◽  
Urinary Bladder Smooth Muscle ◽  
Isolated Rat ◽  
Intestinal Polypeptide
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