OBJECTIVETo study the effect of endogenous carbon monoxide (CO) on the smooth muscle function of the dog penile corpus cavernosum in vitro.

METHODSTissue bioassay was used to measure the corpus cavernosum muscle contraction and relaxation. The production of CO was induced in the corpus cavernosum smooth muscle, and the effect of CO on the penile corpus cavernosum smooth muscle pre-contracted by phenylephrine (PE) was determined.

RESULTSChlorinous hemoglobin could relax the smooth muscle stripes pre-contracted by 10 micromol/L PE. A dose-dependent relaxation was observed. The relaxation responses by 10 -100 micromol/L chlorinous hemoglobin were significant compared with the control group (P < 0. 01). The pretreatment of the muscle stripes with ZnPP-IX or methylthioninium significantly reduced the relaxing effect of chlorinous hemoglobin (P < 0.01).

CONCLUSIONThe relaxing effect of endogenous CO on the smooth muscle of the penile corpus cavernosum depends on the concentration of endogenous CO. The underlying mechanism may involve the pathway from CO to cGMP production.

Animals ; Carbon Monoxide ; physiology ; Dogs ; Dose-Response Relationship, Drug ; Hemin ; pharmacology ; In Vitro Techniques ; Male ; Muscle, Smooth ; drug effects ; physiology ; Penile Erection ; drug effects ; physiology ; Penis ; drug effects ; physiology

To investigate the role of ligustrazine on relaxation of the isolated rabbit corpus cavernosum tissue in vitro, the effects of ligustrazine on the corpus cavernosum were observed by using experimental method of smooth muscle strips. Concentration-responses to phenylephine (PE) and KCl were recorded. The results showed that ligustrazine concentration-dependently depressed the contraction response of smooth muscle strips induced by PE. The maximum percentage relaxation of cavernosal strips by ligustrazine was 74.1% +/- 6.2% (compared with control: 21.9% +/- 5.6%, P < 0.01). Ligustrazine concentration-dependently reduced the amplitude of the contraction induced by cumulative doses of PE or KCl, shifted the cumulative concentration response curves of PE and KCI to the right and depressed their maximal responses. It was concluded that ligustrazine could significantly relax the cavernosal muscle contraction induced by PE in vitro. The results suggested that ligustrazine inhibited calcium ion influx.
Calcium Channels/drug effects ; Muscle Contraction/*drug effects ; Muscle Relaxation/*drug effects ; Muscle, Smooth/*drug effects ; Muscle, Smooth/physiology ; Penis/*drug effects ; Penis/physiology ; Phenylephrine/pharmacology ; Potassium Chloride/pharmacology ; Pyrazines/*pharmacology

SS-cream (Severance Secret cream) is made up of extracts from 9 natural products for treating premature ejaculation (PE). SS-cream has been proved to be effective in the treatment of PE in pilot clinical studies. It has also been found to have a potentiating effect of their erectile capacity in some patients. Therefore, we investigated the pharmacological actions of SS-cream and the extracts of its individual components in rabbit corpus cavernosal smooth muscle to realize the effect of SS-cream on penile erection. Extracts of Bufonis Venenum induced a dose-related contraction of rabbit corpus cavernosal muscle, which was significantly inhibited by phentolamine. Extracts of Caryophylli Flos induced a dose-related relaxation in the muscle strips precontracted with phenylephrine (5 x 10(-6)M; PHE). Caryophylli Flos caused a dose-dependent inhibition of the PHE induced contraction and also inhibited the contractility of Bufonis Venenum. Other extracts, when used individually or in a mixture, induced a dose-related relaxation in the precontracted muscle strips with PHE. SS-cream began to exert a relaxing effect at the concentration of 0.05 mg/ml in the muscle strips precontracted muscle strips with PHE (5 x 10(-6)M); causing dose-dependent relaxation with a maximal effect at 0.2 mg/ml. The relaxation effect of SS-cream was partially inhibited by endothelial disruption and by pretreatment with methylene blue, pyrogallol, atropine, and indomethacin, although they were not statistically significant. The results show that SS-cream has a relaxing effect on cavernosal smooth muscle. And it is partly related with enhancing the NO/cyclic GMP pathway although the relaxation mechanism in detail remains to be elucidated. Therefore, SS-cream may be effective for future treatment of mild erectile dysfunction, in addition to its role for premature ejaculation.
Animal ; Ejaculation/drug effects ; In Vitro ; Male ; Muscle Contraction/drug effects ; Muscle, Smooth/drug effects ; Penile Erection/drug effects ; Penis/*drug effects/physiology ; Plant Extracts/*pharmacology ; Rabbits

Ethanol has various effects on male sexual activity under the influence of direct and indirect, in acute and chronic alcohol ingestion. However, whether acetaldehyde, a principal metabolite of ethanol, may affect penile erection directly has still not been elucidated. This present study was, therefore, designed to clarify the pharmacologic effects of the acetaldehyde on corpus cavernosal smooth muscle. Corpus cavernosal strips were prepared from rabbit penises. Isometric tension changes of rabbit corpus cavernosal strips to various drugs and electrical field stimulation (EFS) in an organ chamber were recorded with a pressure transducer after active muscle tone had been induced by phenylephrine (10(-5) mol/L). At the concentrations employed, acetaldehyde had no effect on the pH of the bathing medium. Acetaldehyde in each concentration did not significantly affect resting tone of the smooth muscle during 30 min incubation. Acetaldehyde suppressed contractility induced by phenylephrine and KCI at 10(-4) mol/L, and relaxation induced by EFS and bethanechol at 10(-3) mol/L and 10(-4) mol/L respectively, but acetaldehyde enhanced relaxation induced by ATP at high acetaldehyde level. Sodium nitroprusside-induced relaxation was not affected at any employed acetaldehyde concentration. This suggests that increasing the acetaldehyde level may contribute to male erectile dysfunction mainly by the inhibition of nitric oxide formation.
Acetaldehyde/pharmacology* ; Animal ; Bethanechol/pharmacology ; In Vitro ; Male ; Muscle Contraction/drug effects ; Muscle Relaxation/drug effects ; Muscle, Smooth/physiology ; Muscle, Smooth/drug effects* ; Nitroprusside/pharmacology ; Penis/physiology ; Penis/drug effects* ; Phenylephrine/pharmacology ; Potassium Chloride/pharmacology ; Rabbits

Ethanol has various effects on male sexual activity under the influence of direct and indirect, in acute and chronic alcohol ingestion. However, whether acetaldehyde, a principal metabolite of ethanol, may affect penile erection directly has still not been elucidated. This present study was, therefore, designed to clarify the pharmacologic effects of the acetaldehyde on corpus cavernosal smooth muscle. Corpus cavernosal strips were prepared from rabbit penises. Isometric tension changes of rabbit corpus cavernosal strips to various drugs and electrical field stimulation (EFS) in an organ chamber were recorded with a pressure transducer after active muscle tone had been induced by phenylephrine (10(-5) mol/L). At the concentrations employed, acetaldehyde had no effect on the pH of the bathing medium. Acetaldehyde in each concentration did not significantly affect resting tone of the smooth muscle during 30 min incubation. Acetaldehyde suppressed contractility induced by phenylephrine and KCI at 10(-4) mol/L, and relaxation induced by EFS and bethanechol at 10(-3) mol/L and 10(-4) mol/L respectively, but acetaldehyde enhanced relaxation induced by ATP at high acetaldehyde level. Sodium nitroprusside-induced relaxation was not affected at any employed acetaldehyde concentration. This suggests that increasing the acetaldehyde level may contribute to male erectile dysfunction mainly by the inhibition of nitric oxide formation.
Acetaldehyde/pharmacology* ; Animal ; Bethanechol/pharmacology ; In Vitro ; Male ; Muscle Contraction/drug effects ; Muscle Relaxation/drug effects ; Muscle, Smooth/physiology ; Muscle, Smooth/drug effects* ; Nitroprusside/pharmacology ; Penis/physiology ; Penis/drug effects* ; Phenylephrine/pharmacology ; Potassium Chloride/pharmacology ; Rabbits

AIMTo evaluate the relaxant effect of verapamil on human corpus cavernosum in vitro and to assess the drug's potential as a treatment for erectile dysfunction (ED).

METHODSPreparations of the human corpus cavernosum were obtained from recently deceased young men who had had normal erectile function. The isometric tension and detailed curves were recorded when contractions induced by 10 micromol/L phenylephrine were reduced by different doses of verapamil or the vehicle control (sterile water). The tension of human corpus cavernosum preparations are described as a percentage of their top tension before adding verapamil or the vehicle. ANOVA and least significant difference tests were used for statistical analysis.

RESULTSDoses of 1 micromol/L, 10 micromol/L and 100 micromol/L verapamil resulted in relaxation of (35.28+/-7.96)%, (55.91+/-6.41)%, (85.68+/-4.16)% after 30 min, respectively. The vehicle control at the same time point produced relaxation of (-0.06+/-10.57)% (P<0.05).

CONCLUSIONVerapamil is significantly effective in relaxing normal human corpus cavernous smooth muscle induced by phenylephrine in vitro and the relaxant effect depends on the concentration of verapamil.

Adult ; Humans ; In Vitro Techniques ; Male ; Muscle Relaxation ; drug effects ; Muscle, Smooth, Vascular ; drug effects ; physiology ; Penis ; drug effects ; physiology ; Verapamil ; pharmacology

OBJECTIVETo investigate the effects of alcohol intake on penile structure and function in rats.

METHODSThirty adult male Wistar rats were randomly divided into two groups: control group and alcohol intake group. They were administered with 2 mL of normal saline and 40% alcohol solution respectively through gastric tubes every day. Three months later, the animal model of alcohol intake was evaluated by modified Nayagida's method, and the effects of alcohol on the rats were studied by sexual behavior, the number of apomorphine-induced penile erection, level of testosterone in the sera, and the content of penile smooth muscle.

RESULTSThe scores of animal model of alcohol intake evaluated by Nayagida's method were 0.66 +/- 2.05 in the control group and 9.26 +/- 5.50 in the alcohol intake group (P < 0.05), which indicated that an animal model of alcohol intake was successfully established. Sexual behavior, the number of apomorphine-induced penile erection, testosterone level in the sera, and the content of penile smooth muscle of the alcohol intake group were all statistically different as compared with the control group (P < 0.05).

CONCLUSIONAlcohol intake induces sexual dysfunction in rats, which may be due to the decline of testosterone level in the sera and decline of penile smooth muscle.

Animals ; Ethanol ; adverse effects ; Female ; Male ; Penis ; anatomy & histology ; drug effects ; physiology ; Rats ; Rats, Wistar ; Sexual Behavior, Animal ; Testosterone ; blood

OBJECTIVETo investigate the ultrasonographic indexes in the evaluation of complete penile erection after oral administration of sildenafil citrate in men with normal erectile function.

METHODSThe subjects lay supine, with the penis raised upwards, its back clinging to the abdomen. The probe was placed at the base of the ventral side of the penis for longitudinal and transverse section scanning. Observations were made on the corpus cavernosum, deep artery and deep dorsal vein of the penis at the time of flaccidity and complete erection after oral administration of sildenafil citrate, respectively.

RESULTSThe examinations were acceptable to all the subjects both physically and psychologically, and all were completed successfully with no complications. Compared with the flaccid state of the penis, obvious changes were observed in the state of complete erection, including marked increases in the diameter of the corpus cavernosum ([18.57 +/- 2.50] mm, increased by [106.8 +/- 62.1]%), the inside diameter of the deep artery ([1.18 +/- 0.26] mm, increased by [54.9 +/- 29.0]%), the peak systolic velocity ([32.5 +/- 10.7] cm/s, increased by [209.3 +/- 112.9]%), and the systolic acceleration ([5.71 +/- 2.71] cm/s2, increased by [179.3 +/- 138.2]%).

CONCLUSIONOral administration of sildenafil citrate followed by ultrasonography is a new approach to the objective evaluation of penile erection, characterized by convenience, safety, non-invasiveness, non-complication, easy acceptability and easy clinical application.

Adult ; Humans ; Male ; Penile Erection ; drug effects ; physiology ; Penis ; diagnostic imaging ; Piperazines ; pharmacology ; Purines ; pharmacology ; Sildenafil Citrate ; Sulfones ; pharmacology ; Ultrasonography

OBJECTIVETo evaluate the application of intracavernous pressure (ICP) monitoring in the electrophysiologic and pharmacologic induction of penile erection.

METHODSThe penile dorsal nerves (DN) of 8 anesthetized adult male rats were isolated and the corpora cavernosa exposed. A heparinized 25-gauge angiocath (intravenous catheter) was inserted into the right corpus cavernosum to monitor the ICP and a 30-gauge needle was inserted into the left corpus cavernosum for intracavernosal drug administration. Penile erection was induced by electrical stimulation of the dorsal nerve (16 Hz frequency, 0.5 ms pulse width, 20 s duration, 4 volts) and intracavernous papaverine hydrochloride injection (0.4 mg). ICP was recorded with the SMUP-PC biological signal process system.

RESULTSIn the anesthetized rats, the baseline level of ICP was (12.3 +/- 3.1) mm Hg and the electrical stimulation of the DN significantly increased ICP[(36.4 +/- 2.3) mm Hg, P < 0.05], which slowly returned to baseline pressure after termination of the electrical stimulation. The intravavernosal administration of papaverine also induced a significant increase in ICP [(28.4 +/- 6.1) mm Hg, P < 0.05].

CONCLUSIONICP monitoring in rats provides a useful scientific tool for in vivo studies of penile erection in experimental rat models. It is of great significance for further studying the physiology of penile erection and the pathogenesis of erectile dysfunction as well as for evaluating the efficacy of novel therapies for erectile dysfunction.

Animals ; Electric Stimulation ; Injections ; Male ; Papaverine ; administration & dosage ; pharmacology ; Penile Erection ; drug effects ; physiology ; Penis ; innervation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the relaxants effects of six extractions from Chinese Herbs (neferine, tetrandrine, kakonein, scutellarin, ginsenoside Rgl and ginsenoside Rb1) on the corpus cavernosum tissue of rabbit in vitro.

METHODSIsolated stripes of rabbit corpus cavernosum tissue were precontracted with 10(-5) mol/L phenylephrine (PE). Relaxation in response to cumulative doses of six extracts at (10(-8) - 10(-3)) mol/L was determined.

RESULTSOn rabbit cavernosal muscle stripes precontracted with PE, neferine, tetrandrine, kakonein and scutellarin showed dose dependent relaxation. IC50 values were 4.60 x 10(-6), 3.73 x 10(-5), 8.03 x 10(-4) and 3.33 x 10(-3) mol/L, respectively. However, in the meantime, it was found that the relaxant effects of ginsenoside Rgl and ginsenoside Rbl less significant to stripes precontracted with PE. When the final concentration was 10(-3) mol/L, the relaxations were only (16.32 +/- 5.45)% and (11.21 +/- 3.10)%.

CONCLUSIONAmong the six extracts which showed relaxant effects to rabbit cavernosal muscle stripes precontracted with PE, neferine had greater functions than the other five extracts.

Animals ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; pharmacology ; In Vitro Techniques ; Male ; Muscle Contraction ; drug effects ; Penis ; drug effects ; physiology ; Rabbits