In vitro and in vivo relaxation of corpus cavernosum smooth muscle by the selective myosin ii inhibitor, blebbistatin

Xin hua Zhang, Memduh Aydin, Dwaraka Kuppam, Arnold Melman, Michael E. DiSanto

Research output: Contribution to journalArticle

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Abstract

Introduction: Blebbistatin (BLEB) is a small cell permeable molecule originally reported as a selective inhibitor of myosin II isoforms expressed by striated muscle and non-muscle cells (IC50 = 0.5-5 μM) with poor inhibition of turkey gizzard smooth muscle (SM) myosin II (IC50 ∼80 μM). However, recently it was found that BLEB can potently inhibit mammalian arterial SM (IC50 ∼5 μM). Aim: To investigate the effect of BLEB on corpus cavernosum SM (CCSM) tone and erectile function (EF). Methods: CC tissue obtained from penile implant patients along with CC, aorta and bladder from adult male rats were used for BLEB organ bath studies. Intracavernosal BLEB was administered to rats and EF was assessed via intracavernous pressure (ICP). Main Outcome Measures: Effects of BLEB on agonist-induced CCSM, aorta and bladder contraction in vitro and ICP in vivo. Results: BLEB completely relaxed human CCSM pre-contracted with phenylephrine (PE) in a dose-dependent manner decreasing tension by 76.5% at 10 μM. BLEB pre-incubation attenuated PE-induced contraction of human CC by ∼85%. Human CC strips pre-contracted with endothelin-1 or KCl were almost completely relaxed by BLEB. Rat CCSM pre-contracted with PE showed BLEB relaxation comparable to human CCSM. BLEB inhibition was similar for rat aorta but slower for bladder. Both maximal ICP and ICP/mean arterial pressure were dose-dependently increased by BLEB intracavernous injections with full erection at 1 micromole. Conclusion: Our novel data reveals that BLEB nearly completely relaxes rat and human CCSM pre-contracted with a variety of potent agonists and exhibits tissue selectivity. Coupled with our in vivo data in which nanomole doses of BLEB significantly increase ICP, our data substantiates an important role for the SM contractile apparatus in the molecular mechanism for EF and suggests the possibility of BLEB binding at myosin II as a therapeutic treatment for ED by targeting SM contractile pathways.

Original languageEnglish (US)
Pages (from-to)2661-2671
Number of pages11
JournalJournal of Sexual Medicine
Volume6
Issue number10
DOIs
StatePublished - 2009

Fingerprint

Smooth Muscle Myosins
Myosin Type II
Smooth Muscle
Pressure
Phenylephrine
Inhibitory Concentration 50
Aorta
Urinary Bladder
In Vitro Techniques
blebbistatin
Penile Prosthesis
Striated Muscle
Endothelin-1

Keywords

  • Cross-bridge cycling
  • Endothelin
  • Erectile function
  • Erectogenic agent
  • Myosin
  • Smooth muscle contraction

ASJC Scopus subject areas

  • Urology
  • Obstetrics and Gynecology
  • Reproductive Medicine
  • Medicine(all)

Cite this

In vitro and in vivo relaxation of corpus cavernosum smooth muscle by the selective myosin ii inhibitor, blebbistatin. / Zhang, Xin hua; Aydin, Memduh; Kuppam, Dwaraka; Melman, Arnold; DiSanto, Michael E.

In: Journal of Sexual Medicine, Vol. 6, No. 10, 2009, p. 2661-2671.

Research output: Contribution to journalArticle

Zhang, Xin hua ; Aydin, Memduh ; Kuppam, Dwaraka ; Melman, Arnold ; DiSanto, Michael E. / In vitro and in vivo relaxation of corpus cavernosum smooth muscle by the selective myosin ii inhibitor, blebbistatin. In: Journal of Sexual Medicine. 2009 ; Vol. 6, No. 10. pp. 2661-2671.
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T1 - In vitro and in vivo relaxation of corpus cavernosum smooth muscle by the selective myosin ii inhibitor, blebbistatin

AU - Zhang, Xin hua

AU - Aydin, Memduh

AU - Kuppam, Dwaraka

AU - Melman, Arnold

AU - DiSanto, Michael E.

PY - 2009

Y1 - 2009

N2 - Introduction: Blebbistatin (BLEB) is a small cell permeable molecule originally reported as a selective inhibitor of myosin II isoforms expressed by striated muscle and non-muscle cells (IC50 = 0.5-5 μM) with poor inhibition of turkey gizzard smooth muscle (SM) myosin II (IC50 ∼80 μM). However, recently it was found that BLEB can potently inhibit mammalian arterial SM (IC50 ∼5 μM). Aim: To investigate the effect of BLEB on corpus cavernosum SM (CCSM) tone and erectile function (EF). Methods: CC tissue obtained from penile implant patients along with CC, aorta and bladder from adult male rats were used for BLEB organ bath studies. Intracavernosal BLEB was administered to rats and EF was assessed via intracavernous pressure (ICP). Main Outcome Measures: Effects of BLEB on agonist-induced CCSM, aorta and bladder contraction in vitro and ICP in vivo. Results: BLEB completely relaxed human CCSM pre-contracted with phenylephrine (PE) in a dose-dependent manner decreasing tension by 76.5% at 10 μM. BLEB pre-incubation attenuated PE-induced contraction of human CC by ∼85%. Human CC strips pre-contracted with endothelin-1 or KCl were almost completely relaxed by BLEB. Rat CCSM pre-contracted with PE showed BLEB relaxation comparable to human CCSM. BLEB inhibition was similar for rat aorta but slower for bladder. Both maximal ICP and ICP/mean arterial pressure were dose-dependently increased by BLEB intracavernous injections with full erection at 1 micromole. Conclusion: Our novel data reveals that BLEB nearly completely relaxes rat and human CCSM pre-contracted with a variety of potent agonists and exhibits tissue selectivity. Coupled with our in vivo data in which nanomole doses of BLEB significantly increase ICP, our data substantiates an important role for the SM contractile apparatus in the molecular mechanism for EF and suggests the possibility of BLEB binding at myosin II as a therapeutic treatment for ED by targeting SM contractile pathways.

AB - Introduction: Blebbistatin (BLEB) is a small cell permeable molecule originally reported as a selective inhibitor of myosin II isoforms expressed by striated muscle and non-muscle cells (IC50 = 0.5-5 μM) with poor inhibition of turkey gizzard smooth muscle (SM) myosin II (IC50 ∼80 μM). However, recently it was found that BLEB can potently inhibit mammalian arterial SM (IC50 ∼5 μM). Aim: To investigate the effect of BLEB on corpus cavernosum SM (CCSM) tone and erectile function (EF). Methods: CC tissue obtained from penile implant patients along with CC, aorta and bladder from adult male rats were used for BLEB organ bath studies. Intracavernosal BLEB was administered to rats and EF was assessed via intracavernous pressure (ICP). Main Outcome Measures: Effects of BLEB on agonist-induced CCSM, aorta and bladder contraction in vitro and ICP in vivo. Results: BLEB completely relaxed human CCSM pre-contracted with phenylephrine (PE) in a dose-dependent manner decreasing tension by 76.5% at 10 μM. BLEB pre-incubation attenuated PE-induced contraction of human CC by ∼85%. Human CC strips pre-contracted with endothelin-1 or KCl were almost completely relaxed by BLEB. Rat CCSM pre-contracted with PE showed BLEB relaxation comparable to human CCSM. BLEB inhibition was similar for rat aorta but slower for bladder. Both maximal ICP and ICP/mean arterial pressure were dose-dependently increased by BLEB intracavernous injections with full erection at 1 micromole. Conclusion: Our novel data reveals that BLEB nearly completely relaxes rat and human CCSM pre-contracted with a variety of potent agonists and exhibits tissue selectivity. Coupled with our in vivo data in which nanomole doses of BLEB significantly increase ICP, our data substantiates an important role for the SM contractile apparatus in the molecular mechanism for EF and suggests the possibility of BLEB binding at myosin II as a therapeutic treatment for ED by targeting SM contractile pathways.

KW - Cross-bridge cycling

KW - Endothelin

KW - Erectile function

KW - Erectogenic agent

KW - Myosin

KW - Smooth muscle contraction

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