cyclic-gmp and Urinary-Bladder--Overactive

During the last decades it turned out that the NO/cGMP signaling cascade is one of the most prominent regulators of a variety of physiological and pathophysiological processes in a broad range of mammalian tissues. Thus cGMP is a key second messenger and targeting this pathway by increasing intracellular cGMP levels is a very successful approach in pharmacology as shown for nitrates, PDE5 inhibitors and more recently for stimulators of the guanylate cyclase. Besides the beneficial effects of cGMP elevation in cardiac, vascular, pulmonary, renal or liver disorders the launch of PDE5 inhibitors for the treatment of erectile dysfunction 10 years ago, has directed a lot of attention to the NO/cGMP signaling in the lower urinary tract. Triggered by the use of PDE5 inhibitors in ED it turned out that cGMP is a common regulatory mechanism for lower urinary tract function also beyond ED. In recent years intense research and development efforts were undertaken to elucidate the role of the NO/cGMP and to fully exploit the therapeutic implications of cGMP elevation in urological disorders in ED and beyond. Therefore we have summarized the effects of cGMP elevation for treatment of erectile dysfunction in males and in females. We have also reviewed the recent pre-clinical and clinical lines of evidence for treatment options of benign prostatic hyperplasia and lower urinary tract symptoms in male patients and overactive bladder and urinary incontinence in female patients. In addition we also touch more speculative concepts using cGMP elevating drugs for the treatment of premature ejaculation, peyornies disease and stone disease.

Topics: Animals; Cyclic GMP; Erectile Dysfunction; Female; Humans; Male; Nephrolithiasis; Nitric Oxide; Penile Induration; Prostatic Hyperplasia; Sexual Dysfunction, Physiological; Signal Transduction; Urinary Bladder, Overactive; Urinary Incontinence

To assess the urodynamic effects of soluble guanylyl cyclase (sGC) stimulator, BAY 41-2272, and activator, BAY 60-2770, (which both are able to induce cGMP synthesis even in the absence of nitric oxide (NO)) alone or in combination with a phosphodiesterase type 5 (PDE5) inhibitor, vardenafil, in a model of partial urethral obstruction (PUO) induced bladder overactivity (BO).. Fifty-six male Sprague-Dawley rats were used, 31 of them underwent PUO. Fourteen rats were used for Western blots to assess PDE5 and sGC expression. For drug evaluation cystometry without anesthesia was performed three days following bladder catheterization.. Obstructed rats showed higher micturition frequency and bladder pressures than non-obstructed animals (Intermicturition Interval, IMI, 2.28 ± 0.55 vs. 3.60 ± 0.60 min (± standard deviation, SD); maximum micturition pressure, MMP, 70.1 ± 8.0 vs. 48.8 ± 7.2 cmH2O; both P < 0.05). In obstructed rats vardenafil, BAY 41-2272, and BAY 60-2770 increased IMI (2.77 ± 1.12, 2.62 ± 0.52, and 3.22 ± 1.04 min; all P < 0.05) and decreased MMP (54.4 ± 2.8, 61.5 ± 11.3, and 51.2 ± 6.3 cmH2O; all P < 0.05). When vardenafil was given following BAY 41-2272 or BAY 60-2770 no further urodynamic effects were observed. PDE5 as well as sGC protein expression was reduced in obstructed bladder tissue.. Targeting sGC via stimulators or activators, which increase the levels of cGMP independent of endogenous NO, is as effective as vardenafil to reduce urodynamic signs of BO. Targeting the NO/cGMP pathway via compounds acting on sGC might become a new approach to treat BO.

Topics: Animals; Benzoates; Biphenyl Compounds; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Disease Models, Animal; Drug Therapy, Combination; Guanylate Cyclase; Hydrocarbons, Fluorinated; Male; Phosphodiesterase 5 Inhibitors; Pyrazoles; Pyridines; Rats; Rats, Sprague-Dawley; Urethral Obstruction; Urinary Bladder; Urinary Bladder, Overactive

Nitric oxide (NO) has been identified an important neurotransmitter involved in the control of the human urinary tract. It has been suggested that NO is one of the factors keeping the bladder relaxed during the filling phase. This function might be mediated by the NO-induced elevation of intracellular cyclic GMP. Prostaglandins (PG) are known to exert contractile effects on the bladder smooth musculature, especially in pathological conditions. The aim of the present study was to examine the effects of a new class of NO donor drugs, combining both anti-phlogistic and NO-donating activity (NCX 2111 and HCT 1026), on the contraction induced by PG or electrical field stimulation (EFS) of isolated human detrusor. Effects were compared to those of sodium nitroprusside (SNP), forskolin, tolterodine, and oxybutynin. Using the organ bath technique, drug effects on the contraction induced by PG ((F2 alpha)) or EFS of isolated human detrusor smooth muscle were investigated. Detrusor strips were also exposed to increasing concentrations of the compounds (0.1 microM - 10 microM) and the accumulation of cyclic GMP and cyclic AMP was determined by means of radioimmunoassays. The tension induced by PG was dose-dependently reversed by the drugs. The rank order of efficacy was: forskolin > SNP > NCX 2111 > HCT 1026. R(max) values ranged from 57% (forskolin) to 24% (HCT 1026). Compounds also dose-dependently reduced the amplitudes of contraction induced by EFS (tolterodine > oxybutynin > NNP = forskolin > HCT 1026 > 2111). The effects of forskolin, HCT 1026, NCX 2111 and SNP were paralleled by an increase in cyclic AMP or cyclic GMP. Our results provide evidence that the NO-cGMP pathway is not of utmost significance in the control of human detrusor smooth muscle. In vitro, the combination of NO-donating with anti-phlogistic activity does not seem to be of functional advantage with regard to the facilitation of detrusor relaxation.

Topics: Anti-Infective Agents; Cyclic GMP; Flurbiprofen; Humans; In Vitro Techniques; Muscle, Smooth; Nitric Oxide; Urinary Bladder, Overactive

Phosphodiesterase type 5 inhibitors (PDE5i), the most widely used drugs for erectile dysfunction, could also improve lower urinary tract symptoms, essentially due to overactive bladder (OAB), a condition hypothesized to be a result of an increased RhoA/Rho-kinase (ROCK) signaling. Phosphorylation/inactivation of RhoA by cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) activity has been described in vascular smooth muscle.. The aim of this paper was to investigate whether vardenafil-induced cGMP accumulation reduces RhoA/ROCK signaling in bladder.. Spontaneously hypertensive rats (SHRs), a strain genetically prone to develop OAB, were treated with vardenafil (10 mg/kg/day) for 2 weeks. Wistar-Kyoto rats (WKY) were used as control. In vitro experiments were performed in human bladder smooth muscle cells (hBCs).. Urodynamic parameters were registered in vivo in anesthetized WKY and SHRs. RhoA/ROCK activity in bladder was evaluated by molecular and functional studies in tissues and cells.. The intercontraction interval and bladder capacity, and were decreased in SHRs and restored by vardenafil. The in vitro relaxant effect of the ROCK inhibitor Y-27632 was higher in bladder strips from SHR than from WKY and reduced by vardenafil. Nomega-nitro-L-arginine-methyl-ester (a NO-synthase inhibitor, 40 mg/kg/day during the last week of the 2-week treatment with vardenafil) partially antagonized vardenafil effect on Y-27632 responsiveness. Vardenafil prevented RhoA membrane translocation/activation, decreased ROCK activity, and increased cGMP levels in vivo (rat) and in vitro (hBCs). Exposing hBCs to vardenafil increased Ser(188) RhoA phosphorylation, to the same extent as the PDE5-insensitive PKG agonist Sp-8-Br-PET-cGMP. Moreover, vardenafil inhibited several RhoA-dependent functions in hBCs, including smooth muscle gene transcription and endothelin-1-induced migration. These effects were reverted by the PKG inhibitor KT 5823, further suggesting a cGMP/PKG-dependency. In hBCs, vardenafil was active in the low nanomolar range.. This is the first study demonstrating that the effect of vardenafil on OAB could be partially determined by a cGMP-dependent RhoA/ROCK signaling inhibition.

Topics: Animals; Blotting, Western; Cyclic GMP; Hypertension; Imidazoles; Muscle Contraction; Muscle, Smooth; Phosphodiesterase 5 Inhibitors; Phosphodiesterase Inhibitors; Piperazines; Rats; Reverse Transcriptase Polymerase Chain Reaction; rho-Associated Kinases; rhoA GTP-Binding Protein; Signal Transduction; Sulfones; Triazines; Urinary Bladder, Overactive; Urodynamics; Vardenafil Dihydrochloride