Ex vivo expression of nitric oxide synthase isoforms (eNOS/iNOS) and calmodulin in human penile cavernosal cells

Effects of ozone treatment on penile erection capacity and nitric oxide synthase levels in diabetic rats

We aimed to determine the effects of ozone treatment on functional and biochemical changes in corpus cavernosum of diabetic rats. A total of 18 rats were included in the study. The rats were divided into the three groups as control, diabetes mellitus, and diabetes mellitus + ozone therapy groups. In the latter, ozone gas mixture was administered intraperitoneally for 2 weeks after the induction of experimental diabetes model. Erectile response was evaluated by determining mean intracavernosal pressure. Tissue neuronal, inducible and endothelial nitric oxide synthase levels were evaluated with commercial ELISA kits. Immunohistochemical evaluation was also performed to determine the expression levels of nitric oxide synthases semiquantatively. Mean intracavernosal pressure and intracavernosal pressure/systemic arterial blood pressure ratio were significantly higher in the diabetes mellitus + ozone therapy group than those of diabetes mellitus group (24.57 ± 6.36 mmHg vs. 5.98 ± 2.04 mmHg, p = 0.005 and 0.81 ± 0.16 vs. 0.26 ± 0.11, p = 0.0001, respectively). The level of penile tissue endothelial nitric oxide synthase was significantly higher in diabetes mellitus + ozone therapy group compared with others (19.28 ± 3.40 ng/mL vs. 13.47 ± 2.06 ng/mL and 13.28 ± 1.48 ng/mL, P = 0.01). Endothelial nitric oxide synthase expression increased significantly with ozone therapy. Our results suggest that ozone therapy may be beneficial in reducing the negative effects of diabetes on erectile dysfunction as a result of enhanced enzymatic activity in endothelial nitric oxide synthase levels.

Therapeutic interventions targeting the nitric oxide system: current and potential uses in obstetrics, bone disease and erectile dysfunction

Nitric oxide is involved in a countless number of physiological processes and is known to have cytoprotective as well as cytotoxic effects. Increased knowledge about the multifaceted role of nitric oxide in a variety of disease states has led to the design of multiple treatment strategies involving the nitric oxide system. The current review focuses on recent research advances in the fields of obstetrics, bone disease and erectile dysfunction that have led to current or potential future therapies involving nitric oxide.

Effects of sildenafil on erectile activity in mice lacking neuronal or endothelial nitric oxide synthase

1. Using an in vivo model of erectile activity, the effects of sildenafil were studied in mice lacking neuronal or endothelial nitric oxide synthase (nNOS and eNOS, respectively). 2. Under pentobarbitone anaesthesia, intracavernous pressure (ICP) and mean arterial pressure (MAP) were monitored continuously in wild-type, nNOS-/- and eNOS-/- mice. The magnitude of erectile activity was quantified as the ratio of ICP to MAP. 3. No differences in basal ICP or MAP were observed amongst wild-type, eNOS-/- and nNOS-/- mice. Electrical stimulation of the cavernous nerve (ESCN; 4.0 V, 16 Hz, 1 ms, 30 s) evoked increases in ICP and ICP/MAP as well as penile tumescence. Responses to ESCN were reduced in nNOS-/-, but not in eNOS-/- mice. 4. L-NAME (50 mg kg(-1), i.v.) significantly increased MAP and attenuated erectile responses in both wild-type and eNOS-/- mice. 5. Sildenafil (1 mg kg(-1), i.v.) augmented electrically-evoked erectile activity in a voltage-dependent manner in wild-type mice and facilitated erectile responses in eNOS-/- mice. By contrast, sildenafil failed to augment the diminished erectile responses in mice lacking the nNOS isoform. 5. These data reveal the relative importance of nNOS, compared to eNOS, as the critical NOS isoform in the control of erectile function and illustrate that the nNOS isoform is required for sildenafil-induced facilitation of erectile responses in vivo in mice.