Recent evidence implicates NO (Nitric oxide) as the principal mediator in an erection. To investigate the role of NO in the human erectile function, we studied the distribution pattern of nitroxergic fibers in the corpus cavernosum specimens obtained from 38 men using nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry. Diffusely scattered delicate nerve fibers showing blue color reaction after NADPH-d histochemical staining were observed in normal control specimens from potent men. The neurogenic impotence group showed a statistically-significant decrease in the number of positive fibers compared to the normal control group. The number of positive fibers in the non-neurogenic impotence group was decreased compared to the normal control group but was statistically insignificant. With nitric oxide synthase (NOS) immunohistochemical stain, immunoreactive nerve bundles were easily seen in normal control specimens from potent men. NOS immunoreactive nerve bundles were contained within the corpus cavernosa which stained with NADPH-d reaction. Our results suggest that nitric oxide, a potent smooth muscle relaxing neurotransmitter in the autonomic nervous system, plays a physiologic role in erectile function and NADPH-d enzyme histochemical staining on the biopsied corpus cavernosum may be used as an important diagnostic method in the evaluation of neurogenic impotence.
Histocytochemistry ; Human ; Impotence/enzymology* ; Male ; NADPH Dehydrogenase/metabolism ; Nitric-Oxide Synthase/metabolism* ; Penis/enzymology* ; Tissue Distribution

OBJECTIVESTo investigate the effect of aging on the expression of nitric oxide synthase I (NOS I) and the activity of nitric oxide synthase in the rat penis.

METHODSThirty male rats from three age groups(adult, old and senescent) were investigated: 1. The expressions of NOS I protein and mRNA in the penis were detected by Western blot and RT-PCR, respectively. 2. NOS activity in the penis was detected with ultraviolet spectrophotometry.

RESULTSIn rats of the old and the senescent groups, the expression of NOS I protein decreased significantly as compared to that of the adult group. NOS I mRNA expression was well related to its protein expression. NOS activity had no statistical difference between the adult group and the old group, but it reduced significantly in the senescent group as compared to that of the adult group(P < 0.01).

CONCLUSIONSIt is maybe one of the main mechanisms of erectile dysfunction in the aging male that the aging causes the decreases of NOS I protein and mRNA expression and NOS activity.

Aging ; metabolism ; Animals ; Erectile Dysfunction ; enzymology ; Male ; Nitric Oxide Synthase ; biosynthesis ; genetics ; Nitric Oxide Synthase Type I ; Penis ; enzymology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the expressions of cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) in the corpus cavernosum smooth muscle of castrated rats and their roles in erectile dysfunction after castration.

METHODSWe randomly assigned 40 eight-week-old male SD rats to groups A (2-week sham-operation), B (4-week sham-operation), C (2-week castration) and D (4-week castration). We determined the level of serum testosterone (T) and the expressions of CBS and CSE in the corpus cavernosum smooth muscle of the rats after operation using immunohistochemistry and RT-PCR.

RESULTSThe T level was significantly decreased in groups C ([11.85 +/- 6.73] nmol/L) and D ([1.96 +/- 1.23] nmol/L) as compared with A ([89.65 +/- 17.13] nmol/L) and B ([106.75 +/- 19.68] nmol/L) (P < 0.05). CBS and CSE were expressed in all groups of rats, but the relative expressions of CBS and CSE mRNA were significantly lower in groups C (0.93 +/- 0.14 and 0.87 +/- 0.20) and D (0.79 +/- 0.17 and 0.71 +/- 0.12) than in A (2.13 +/- 0.65 and 1.93 +/- 0.15) and B (2.07 +/- 0.53 and 1.89 +/- 0.45) (P < 0. 05), so were the optical density values (IA) of the CBS and CSE proteins, 130.35 +/- 23.56 and 93.56 +/- 36.64 in group C and 80.29 +/- 29.65 and 58.56 +/- 19.95 in group D, as compared with 310.57 +/- 130.56 and 269.56 +/- 116.76 in group A and 349.68 +/-112.35 and 298.35 +/- 100.76 in group B (P < 0.05). The androgen level was positively correlated with the expressions of CBS and CSE in the corpus cavernosum smooth muscle of the rats.

CONCLUSIONAndrogen regulates erectile function via the expressions of CBS and CSE.

Animals ; Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Male ; Muscle, Smooth ; enzymology ; Orchiectomy ; Penis ; enzymology ; Rats ; Rats, Sprague-Dawley ; Testosterone ; blood

OBJECTIVETo explore the influence of buried penis on nitric oxide synthase (NOS) activity of the corpus cavernosum in rats.

METHODSThe experimental model of concealed penis was established by intra-pocket-suture of the root of the penis. Two hundred and forty rats were equally randomized into a 2, a 4 and a 6 months group, each further divided into a buried (n = 50), a sham operation (n = 15) and a normal subgroup (n = 15). The development of the corpus cavernosum was surveyed by measuring its weight and the ratio to the body weight, followed by determination of NOS activity in the corpus cavernosum by spectrophotometry.

RESULTSNo significant differences were found in the corpus cavernosum weight, the body weight and their ratio among the buried, sham operation and normal groups in any experimental stage (P > 0.05). Buried penis decreased NOS activity in the 4- and 6-month groups (P < 0.05 and P < 0.01) compared with the normal group, but effected no significant change in the 2-month group.

CONCLUSIONBuried penis decreases the NOS activity of the corpus cavernosum in a positively time-related manner, but with no significant influence on its appearance and weight.

Animals ; Disease Models, Animal ; Erectile Dysfunction ; enzymology ; physiopathology ; Male ; Nitric Oxide Synthase ; metabolism ; Penis ; abnormalities ; enzymology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Spectrophotometry

The present study was undertaken to investigate the role of nitric oxide (NO) in erectile physiology by correlating its action with the existence and activity of nitric oxide synthase (NOS), which produces NO. We applied Western blot analysis in both human and rat penile tissue. In the rat, reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining and spectrophotometric assay were also performed, in addition to in vivo electroerection study with pharmacological manipulation. Western blot analysis identified a protein of 155 KDa identical to the neural form of NOS in the human and rat penis. The NOS blot densities in the two species were similar, and both were lower than that in the rat cerebellum. Histochemical staining localized NOS to neurons innervating the corpora cavernosa, including the pelvic plexus, the cavernosal nerves and their terminal fibers within the corporeal erectile tissue, and dorsal penile nerves. NOS activity was also found in the cerebellum, urethra, penis, and urinary bladder, in decreasing order of intensity. Intracavernous injections of NOS inhibitor (L-NOARG or L-NAME in concentrations from 10(-6) M to 10(-3) M suppressed electrostimulation-induced erection in a concentration-dependent manner. Subsequent intracavernous injection of L-Arginine (10(-2) M) partially restored the erection. The neural form of constitutive NOS in the corpora cavernosa synthesizes NO, which mediates penile erection. Determination of cavernosal NOS expression or activity may permit characterization of certain pathological conditions that cause impotence.
Animal ; Human ; Male ; Nitric Oxide/physiology* ; Nitric-Oxide Synthase/metabolism ; Penile Erection/physiology* ; Penis/enzymology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the expression of Rho-kinase and heme oxygenase and the interaction among NOS/NO, HO/CO and RhoA/Rho-kinase in the corpus cavernosum of spontaneous hypertensive rats (SHRs).

METHODSA series of electric stimuli were applied to the corpus cavernosum nerves of 7 SHRs, the changes of ICP/MAP observed continuously and the expressions of ROCK2, HO-2 and eNOS analyzed by Western blot and immunohistochemistry. Another 7 WKY rats were taken as controls.

RESULTSCompared with the controls, ICP/MAP did not rise obviously (P < 0.05), HO-2 dropped sharply (P = 0.006) and the expression of the ROCK2 protein was elevated markedly (P = 0.017) in the SHRs. Immunohistochemistry showed HO-2 to be distributed in the smooth muscle cells and nervous cells of the corpus cavernosum, and eNOS mainly in the vascular endothelial cells. The expressions of HO-2 and eNOS were obviously reduced in the SHRs.

CONCLUSIONNOS/NO, HO/CO and RhoA/Rho-kinase are related with erectile dysfunction in SHRs and may interact on one another.

Animals ; Blotting, Western ; Erectile Dysfunction ; enzymology ; physiopathology ; Heme Oxygenase (Decyclizing) ; metabolism ; Hypertension ; enzymology ; physiopathology ; Immunohistochemistry ; Male ; Penis ; enzymology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; rho-Associated Kinases ; metabolism

OBJECTIVETo investigate the expressions of cystathionine gamma-lyase (CSE) and cystathionine beta-synthase (CBS) in the corpus cavernosum of spontaneous hypertensive rats (SHR) and their relationship with erectile dysfunction.

METHODSThis study included 10 male SHRs and 10 healthy male Wistar-Kyoto (WKY) rats as controls, all aged 12 weeks. We applied a series of electric stimuli to the major pelvic ganglions of the rats, observed changes in the ratio of intracavernosal to mean arterial blood pressure (ICP/MAP), measured the levels of serum testosterone (T) and endogenous H2S, and determined the expressions of CSE and CBS in the corpus cavernosum by Western blot and immunohistochemistry.

RESULTSNo obvious difference was found in the serum T level between the two groups. Compared with the WKY rats, the SHRs showed significant reduction in the ICP/MAP ratio, the contents of plasma H2S ([21.92 +/- 2.75] micromol/L vs [10.49 +/- 1.35] micromol/L, P < 0.05) and endogenous corpus cavernosal H2S ([87.67 +/- 2.12] nmol/mg prot vs [52.60 +/- 3.44] nmol/mg prot, P < 0.05), the level of endogenous H2S synthesis ([4.35 +/- 0.32] nmol/mg per min vs [1.14 +/- 0.07] nmol/mg per min, P < 0.05) and the expressions of CBS and CSE (P < 0.05). Immunohistochemistry showed that CSE and CBS were distributed mainly in the smooth muscle cells and vascular endothelial cells of the corpus cavernosum. The ICP/MAP ratio was highly positively correlated with the expressions of CSE (r = 0.977, P < 0.05) and CBS (r = 0.955, P < 0.05) in the corpus cavernosal tissue.

CONCLUSIONHypertension inhibits endogenous H2S synthesis by suppressing the expressions of CSE and CBS in the corpus cavernosum, which might be related with hypertension-induced reduction of erectile function.

Animals ; Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Gene Expression Regulation ; Hydrogen Sulfide ; blood ; Hypertension ; metabolism ; Male ; Penis ; enzymology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY

OBJECTIVETo investigate the effects of growth hormone (GH) on the erectile function and the number of neuronal nitric oxide synthase (nNOS) -containing nerve fibers in the penis of aged rats.

METHODSTwenty-four aged male SD rats (18 months) were randomized into 2 groups: GH intervention group and control group. After four and eight weeks, a half of each group were selected and tested for erectile function after apomorphine (APO) injection and then sacrificed for the detection of nNOS-containing nerve fibers in the penis by streptavidin-peroxidase conjugated method (SP method).

RESULTSAfter four weeks, the erectile function and the number of nNOS-containing nerve fibers showed no significant difference between the GH intervention group and the control group (P > 0.05). After eight weeks, the erection frequency was significantly different (P < 0.05) between the two groups, while the erection rate was not. The number of nNOS-containing nerve fibers in the GH intervention group was significantly larger than that in the control group (P < 0.01).

CONCLUSIONGH enhances the regeneration of nNOS-containing nerve fibers in the penis and improves the erectile function of the aged rat.

Animals ; Apomorphine ; pharmacology ; Human Growth Hormone ; pharmacology ; Immunohistochemistry ; Male ; Nerve Fibers ; enzymology ; physiology ; Nerve Regeneration ; drug effects ; Nitric Oxide Synthase Type I ; analysis ; Penile Erection ; drug effects ; Penis ; enzymology ; innervation ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the mechanism of erectile dysfunction (ED) in rat models with chronic renal failure (CRF).

METHODSChronic renal failure was induced by adult male Sprague-Dawley rats, which were subjected to an excisional 5/6 nephrectomy. The rats in NCRF group and CRF group were divided into three groups randomly. Injected with apomorphine(APO, 80 microg/kg), penile erections of three groups were observed and noted by the 2nd week, 4th week respectively and 6th week from the 14th day of 5/6 nephrectomy and experimental models of ED with CRF were selected; NOS activity was examined and the microstructures of penile were observed under optical microscope with computer configuration image analysis system in selected rat models.

RESULTSCompared with the controls, the areas of smooth muscle and NOS activity in the penile cavernous tissue of ED rats with CRF decreased significantly (P < 0.01 or P < 0.05) , and collagen fibers slightly increased, and these alterations had close correlations with the duration of CRF. The

CONCLUSIONSPenile erection is seriously affected in rats with CRF. The decreases of areas of blood sinus had no obvious changes. the number of smooth muscles and NOS activity might be the most important factors.

Animals ; Disease Models, Animal ; Erectile Dysfunction ; enzymology ; pathology ; Kidney Failure, Chronic ; complications ; pathology ; Male ; Muscle, Smooth ; diagnostic imaging ; Nephrectomy ; Nitric Oxide Synthase ; metabolism ; Penis ; diagnostic imaging ; enzymology ; Rats ; Rats, Sprague-Dawley ; Ultrasonography

UNLABELLEDOCTOBER: To explore the effects of the glucagon-like peptide 1 (GLP-1) liraglutide on the penile erectile function of rats with diabetic erectile dysfunction (DED) by observing the impact of liraglutide on the expression of eNOS in the corpus cavernosum of diabetic rats.

METHODSWe randomly divided 30 six-week-old male SD rats into a normal control (n = 10) and an experimental group (n = 20) , established models of diabetes mellitus (DM) in the experimental rats, and subdivided them into a DM (n = 8) and a GLP-1 group (n = 8) to receive intramuscular injection of normal saline and liraglutide at 5 mg per kg of the body weight per day, respectively. After 12 weeks of intervention, we obtained the levels of FPG, FINS, TG, TC, HDL-C, LDL-C, testosterone, and IL-6 and the indexes of Homa-IR and Homa-β, detected the expressions of Akt/p-Akt and eNOS/p-eNOS in the corpus cavernosum by Western blot, and compared the erectile function between different groups.

RESULTSThe frequency and rate of penile erection were significantly lower in the DM group than in the GLP-1 and normal control groups (P < 0.05) and also lower in the GLP-1 group than in the normal controls (P < 0.05). Immunofluorescence staining showed the expression of eNOS mainly in the cytoplasm of the cavernosal vessels and sinusoidal endothelial cells, markedly lower in the DM and GLP-1 groups than in the normal rats (P < 0.05), but higher in the GLP-1 than in the DM group (P < 0.05). The level of eNOS/p-eNOS in the penile tissue was significantly decreased in the DM and GLP-1 groups in comparison with the normal controls (P < 0.01 or P < 0.05), while that of p-eNOS was markedly increased in the GLP-1 group as compared with the DM group (P < 0.05). No statistically significant differences were observed in the Akt level among the three groups of animals (P > 0.05). The expression of p-Akt was remarkably reduced in the DM and GLP-1 groups in comparison with the control rats (P < 0.01 or P < 0.05), but higher in the GLP-1 than in the DM group (P < 0.05).

CONCLUSIONGLP-1 can protect the function of endothelial cells in the corpus cavernosum and improve the erectile function of DED rats by regulating the Akt/ eNOS signaling pathway, which indicates that GLP-1 could be an important option for the treatment and prevention of DED.

Animals ; Blotting, Western ; Diabetes Mellitus, Experimental ; Erectile Dysfunction ; drug therapy ; enzymology ; Hypoglycemic Agents ; pharmacology ; Liraglutide ; pharmacology ; Male ; Nitric Oxide Synthase Type III ; metabolism ; Penile Erection ; drug effects ; Penis ; drug effects ; enzymology ; physiopathology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Testosterone ; blood