Animals ; In Vitro Techniques ; Muscle Contraction ; drug effects ; Muscle, Smooth ; drug effects ; physiology ; Progesterone ; pharmacology ; Rabbits ; Trachea ; drug effects

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

OBJECTIVETo investigate the effect of growth hormone secretagogue(ghrelin) on the contraction and relaxation of small intestinal smooth muscle in rats and its mechanism.

METHODSTwenty-four vagotomized rats were injected intraperitoneally with different concentrations of ghrelin (0, 20, 40, 80 μg/kg). The small intestinal transit were observed. The effect of ghrelin(0.01, 0.1, 0.5, 1.0 μmol/L) on the contraction and relaxation of rat small intestinal smooth muscle strips was observed in vitro in the presence of carbachol(50 nmol/L), the locations of ghrelin receptors(GHS-R1a) on different cells in small intestinal muscle layers were detected by immunofluorescence.

RESULTSWith the increase of concentrations, ghrelin elevated the percentage of small intestinal transit[(25.4±1.0)%, (33.7±1.9)%, (39.3±2.4)%, (44.7±2.1)%] in a dose-dependent manner, and the differences were statistically significant among groups(P<0.05). Ghrelin could also enhance the contraction [(67.0±2.4)%,(149.5±3.3)%, (187.1±4.7)%, (213.5±3.4)%] and relaxation[(35.3±1.1)%, (62.9±3.8)%, (79.6±2.7)%, (94.6±2.2)%] of smooth muscle strips mediated by Cch in a dose-dependent manner, and the differences were statistically significant among groups(P<0.05). Immunofluorescence revealed that ghrelin receptors mainly located on membrane of the nerve cells in the muscle layers, while no receptors were observed on membrane of the smooth muscle cells.

CONCLUSIONGhrelin may enhance the effect of the contraction and relaxation of the rat small intestinal smooth muscle mediated by cholinergic neurotransmitters by activating the nerve cells in the enteric plexus.

Animals ; Gastrointestinal Motility ; Ghrelin ; pharmacology ; Intestine, Small ; drug effects ; physiology ; Male ; Muscle Contraction ; drug effects ; physiology ; Muscle, Smooth ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley

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

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

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

Acetylcholine ; metabolism ; physiology ; Animals ; Cholinergic Agonists ; pharmacology ; Male ; Muscle Contraction ; drug effects ; physiology ; Muscle Relaxation ; drug effects ; physiology ; Muscle, Smooth ; drug effects ; pathology ; physiopathology ; Rabbits ; Random Allocation ; Receptors, Cholinergic ; physiology ; Synaptic Transmission ; drug effects ; Urinary Bladder ; drug effects ; innervation ; physiopathology

Animals ; Intestines ; cytology ; drug effects ; physiology ; Meperidine ; pharmacology ; Mice ; Mice, Inbred Strains ; Muscle, Smooth ; drug effects ; physiology ; 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