Supplementation with Spirulina platensis Prevents Damage to Rat Erections in a Model of Erectile Dysfunction Promoted by Hypercaloric Diet-Induced Obesity.

Erectile dysfunction (ED) is the inability to achieve and/or maintain a penile erection sufficient for sexual satisfaction. Currently, many patients do not respond to the pharmacotherapy. The effects of a supplementation with Spirulina platensis, were evaluated in a model of ED induced by hypercaloric diet consumption. Wistar rats were divided into groups fed with standard diet (SD) or hypercaloric diet (HD) and supplemented with this alga at doses of 25, 50 or 100 mg/kg. Experimental adiposity parameters and erectile function were analyzed. In SD groups, Spirulina platensis reduced food intake, final body mass and adiposity index, and increased the total antioxidant capacity (TAC) of adipose tissue. However, no change was observed in erectile function. In the HD group, without Spirulina supplementation, a decrease in food intake was observed, in addition to an increase of final body mass, weight gain, adipose reserves, and adiposity index. Additionally, reduction in the number and increase in the latency of penile erection and adipose malondialdehyde levels, as well as a reduction in TCA was noted. Furthermore, cavernous contractility was increased, and the relaxing response was decreased. Interestingly, these deleterious effects were prevented by the algae at doses of 25, 50 and/or 100 mg/kg. Therefore, the supplementation with S. platensis prevents damages associated to a hypercaloric diet consumption and emerges as an adjuvant the prevention of ED.

Essential oil from Xylopia frutescens Aubl. reduces cytosolic calcium levels on guinea pig ileum: mechanism underlying its spasmolytic potential.

BACKGROUND: Xylopia frutescens Aubl. (embira, semente-de-embira or embira-vermelha), is used in folk medicine as antidiarrheal. The essential oil from its leaves (XF-EO) has been found to cause smooth muscle relaxation. Thus, the aim of this study was to investigate the spasmolytic action by which XF-EO acts on guinea pig ileum. METHODS: The components of the XF-EO were identified by gas chromatography-mass spectrometry. Segments of guinea pig ileum were suspended in organ bath containing modified Krebs solution at 37 °C, bubbled with carbogen mixture under a resting tension of 1 g. Isotonic contractions were registered using kymographs and isometric contractions using force transducer coupled to an amplifier and computer. Fluorescence measurements were obtained with a microplate reader using Fluo-4. RESULTS: Forty-three constituents were identified in XF-EO, mostly mono- and sesquiterpenes. XF-EO has been found to cause relaxation on guinea pig ileum. The essential oil inhibited in a concentration-dependent manner both CCh- and histamine-induced phasic contractions, being more potent on histamine-induced contractions as well as antagonized histamine-induced cumulative contractions in a non-competitive antagonism profile. XF-EO relaxed in a concentration-dependent manner the ileum pre-contracted with KCl and histamine. Since the potency was smaller in organ pre-contracted with KCl, it was hypothesized that XF-OE would be acting as a K(+) channel positive modulator. In the presence of CsCl (non-selective K(+) channel blocker), the relaxant potency of XF-OE was not altered, indicating a non-participation of these channels. Moreover, XF-EO inhibited CaCl2-induced cumulative contractions in a depolarizing medium nominally without Ca(2+) and relaxed the ileum pre-contracted with S-(-)-Bay K8644 in a concentration-dependent manner, thus, was confirmed the inhibition of Ca(2+) influx through Cav1 by XF-EO. In cellular experiments, the viability of longitudinal layer myocytes from guinea pig ileum was not altered in the presence of XF-OE and the Fluo-4-associated fluorescence intensity in these intestinal myocytes stimulated by histamine was reduced by the essential oil, indicating a [Ca(2+)]c reduction. CONCLUSION: Spasmolytic action mechanism of XF-EO on guinea pig ileum can involve histaminergic receptor antagonism and Ca(2+) influx blockade, which results in [Ca(2+)]c reduction leading to smooth muscle relaxation.

A review of the pathophysiology and the role of ion channels on bronchial asthma.

Asthma is one of the main non-communicable chronic diseases and affects a huge portion of the population. It is a multifactorial disease, classified into several phenotypes, being the allergic the most frequent. The pathophysiological mechanism of asthma involves a Th2-type immune response, with high concentrations of allergen-specific immunoglobulin E, eosinophilia, hyperreactivity and airway remodeling. These mechanisms are orchestrated by intracellular signaling from effector cells, such as lymphocytes and eosinophils. Ion channels play a fundamental role in maintaining the inflammatory response on asthma. In particular, transient receptor potential (TRP), stock-operated Ca2+ channels (SOCs), Ca2+-activated K+ channels (IKCa and BKCa), calcium-activated chloride channel (TMEM16A), cystic fibrosis transmembrane conductance regulator (CFTR), piezo-type mechanosensitive ion channel component 1 (PIEZO1) and purinergic P2X receptor (P2X). The recognition of the participation of these channels in the pathological process of asthma is important, as they become pharmacological targets for the discovery of new drugs and/or pharmacological tools that effectively help the pharmacotherapeutic follow-up of this disease, as well as the more specific mechanisms involved in worsening asthma.

Erectile Dysfunction: Key Role of Cavernous Smooth Muscle Cells.

Erectile dysfunction is increasingly affecting men, from the elderly to young adults, being a sexual disorder related to the inability to generate or maintain a penile erection. This disorder is related to psychosocial factors such as anxiety, depression, and low self-esteem, to organic factors such as the presence of preexisting conditions like hypertension, diabetes and dyslipidemia. The pathophysiology of the disease is related to changes in the neurotransmission of the autonomic or the non-cholinergic non-adrenergic nervous system, as well as the release of local mediators, such as thromboxane A2 and endothelin, and hormonal action. These changes lead to impaired relaxation of cavernous smooth muscle, which reduces local blood flow and impairs penile erection. Currently, therapy is based on oral vasodilation, such as sildenafil, tadalafil, vardenafil and iodenafil, or by direct administration of these agents into the corpus cavernosum or by intraurethral route, such as alprostadil and papaverine. Despite this, studies that consolidate the understanding of its pathophysiological process contribute to the discovery of new more efficient drugs for the treatment of erectile dysfunction. In this sense, in the present work an extensive survey was carried out of the mechanisms already consolidated and the most recent ones related to the development of erectile dysfunction.

Essential oil from Lippia microphylla Cham. modulates nitric oxide pathway and calcium influx to exert a tocolytic effect in rat uterus.

The essential oil of Lippia microphylla (LM-OE) presents several pharmacological activities. This work evaluates the tocolytic effect of LM-OE on rats. LM-OE inhibited phasic contractions and relaxed tonic contractions on rat uterus. Considering that nitric oxide (NO) pathway regulates uterine contraction, LM-OE potency was attenuated in the presence of NO synthase (NOS) inhibitor and this reduction was reversed in the presence of a NOS substrate. Similarly, the relaxant potency of LM-OE was reduced in the presence of soluble guanylyl cyclase (sGC) and protein kinase G (PKG) inhibitors. LM-OE also demonstrates a positive modulation of large and small conductance calcium-activated, voltage-gated and adenosine triphosphate-sensitive potassium channels and inhibited curves to CaCl2 as well as relaxed the uterus pre-contracted by S-(-)-Bay K8644, suggesting voltage-gated calcium channels type-1 (CaV1) blockade. Thus, the tocolytic effect of LM-OE on rat involves positive modulation of NO/NOS/sGC/PKG/K+-channels pathway and Ca2+ influx blockade through CaV1.[Formula: see text].

Oceanapia magna Sponge Presents Dual Effect on the Gastrointestinal Motility of Rodents: In Vitro and In Vivo Assays.

Oceanapia magna Santos-Neto, Nascimento, Cavalcanti and Pinheiro sponges are distributed across tropical worldwide seas. Some studies of marine products have shown interesting activities in smooth muscle models. Hence, we assessed the effect of the ethanolic extract of Oceanapia magna. (OC-EtOH) on acute toxicity and gastrointestinal motility (in vitro and in vivo) in rodent models. On guinea pig ileum, OC-EtOH induced a concentration dependent contraction on basal tonus, which was not inhibited by atropine, but in the presence of pyrilamine or verapamil, the effect was antagonized. Contrastingly, on KCl- or histamine-induced contractions, OC-EtOH presented a transient contraction followed by a concentration-dependent relaxation. Moreover, OC-EtOH presented a relaxant profile on cumulative curves to CaCl2 and tonic contraction induced by S-(-)-BayK8644, through Cav blockade. The acute toxicity assay showed that OC-EtOH (2,000 mg/kg, p.o.) did not present any sign of toxicity in female mice. Additionally, OC-EtOH presented antidiarrheal effect in mice, increased the intestinal normal transit and reduced the castor oil-induced intestinal transit. Thus, OC-EtOH presented a dual effect on guinea pig ileum promoting contraction through activation of H1 and CaV, and relaxation through CaV blockade, besides the effect on upper gastrointestinal transit in mice, showing a potential medicinal use of this sponge in intestinal diseases such as diarrhea.

Toxicological and Pharmacological Activities of Leptohyptis macrostachys (Benth.) Harley and J.F.B.Pastore (Lamiaceae) on Intestinal Smooth Muscle.

Leptohyptis macrostachys, previously known as Hyptis macrostachys Benth., is used in folk medicine to relieve the symptoms of asthma, cough, and bronchitis. Recently, we showed that the ethanol extract obtained from Leptohyptis macrostachys has selective spasmolytic activity on guinea pig ileum. Therefore, the aim of this study was to characterize the spasmolytic mechanism of this extract, investigated whether it presents toxicological and antidiarrheal activities. Therefore, the crude ethanolic extract of Leptohyptis macrostachys was analyzed by high-performance liquid chromatographic-diode array detection (HPLC-DAD). The spasmolytic effect was evaluated on guinea pig ileum, toxicological activity using rats and antidiarrheal activity using male and female mice. In HPLC-DAD analysis, Rosmarinic acid (5.44%) was the most abundant phenolic compound, being considered as a chemical marker. The spasmolytic potency of the extract on histamine-induced contraction was reduced in the presence of 1 mM TEA+, a selective big-conductance K+ channels blocker (BKCa). The extract produces a dose-dependent antidiarrheal activity, inhibiting equipotently defecation frequency and liquid stool formation. In addition, the extract has inhibited in a dose-dependent manner both castor oil-induced intestinal transit and intestinal fluid content. Thus, the spasmolytic activity of the extract involves positive modulation of BKCa and its antidiarrheal activity is related to inhibition of intestinal motility and secretion.

A Guinea Pig Model of Airway Smooth Muscle Hyperreactivity Induced by Chronic Allergic Lung Inflammation: Contribution of Epithelium and Oxidative Stress.

Asthma is a heterogeneous disease of the airways characterized by chronic inflammation associated with bronchial and smooth muscle hyperresponsiveness. Currently, different murine models for the study of asthma show poor bronchial hyperresponsiveness due to a scarcity of smooth muscle and large airways, resulting in a failure to reproduce smooth muscle hyperreactivity. Thus, we aimed to standardize a guinea pig model of chronic allergic lung inflammation mimicking airway smooth muscle hyperreactivity observed in asthmatics (Asth). Animals were randomly divided into a control group (Ctrl), which received saline (0.9% NaCl), and the Asth group, subjected to in vivo sensitization with ovalbumin (OVA) nebulization. Morphological analysis was performed by hematoxylin-eosin staining. Bronchial hyperresponsiveness was evaluated by nebulization time in the fifth, sixth, and seventh inhalations (NT5-7) and tracheal isometric contractions were assessed by force transducer. Total antioxidant capacity was measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and protein expression by Western blot. Histologically, the Asth group developed peribronchial cellular infiltrate, epithelial hyperplasia and smooth muscle thickening. After the fourth nebulization, the Asth group developed bronchial hyperreactivity. The trachea from the Asth group contracted after in vitro stimulation with OVA, differing from the Ctrl group, which showed no response. Additionally, airway smooth muscle hyperreactivity to carbachol and histamine was observed in the Asth group only in intact epithelium preparations, but not to KCl, and this effect was associated with an augmented production of reactive oxygen species. Moreover, lung inflammation impaired the relaxant potency of isoproterenol only in intact epithelium preparations, without interfering with nifedipine, and it was found to be produced by transforming growth factor-ß negative modulation of ß adrenergic receptors and, furthermore, big-conductance Ca2+-sensitive K+ channels. These effects were also associated with increased levels of phosphatidylinositol 3-kinases but not extracellular signal-regulated kinases 1/2 or phosphorylation, and augmented α-actin content as well, explaining the increased smooth muscle mass. Furthermore, pulmonary antioxidant capacity was impaired in the Asth group. Therefore, we developed a standardized and easy-to-use, reproducible guinea pig model of lung inflammation that mimics airway smooth muscle hypercontractility, facilitating the investigation of the mechanisms of bronchial hyperresponsiveness in asthma and new therapeutic alternatives.

Hypercaloric Diet Establishes Erectile Dysfunction in Rat: Mechanisms Underlying the Endothelial Damage.

Obesity is characterized by an excessive increase in body mass, leading to endothelial damage that may favor the development of erectile dysfunction (ED). ED is defined as the inability to achieve or maintain a penile erection long enough to have a sexual intercourse. In this context, different ED models were developed, however the high price of special animals or the long period to establish the disease has limited studies in this field. Therefore, this study proposed to establish and characterize a novel model of ED in rats associated to a hypercaloric diet consumption. Animals were randomly divided into control group (CG), which received a standard diet, and obese group (OG), fed with a hypercaloric diet during 8 weeks. Rat's erectile function was evaluated in vivo and in vitro. Food and caloric intake of OG were reduced compared to CG, due to an increased diet energy efficiency. However, OG presented an increased body mass, inguinal, retroperitoneal and epididymal adipose tissues, as well as body adiposity index at the end of experimental protocol. In erectile function analysis, there was a decrease in the number and the latency of penile erections in OG. Additionally, the contractile reactivity of corpus cavernosum was increased in OG, favoring penile detumescence and related to a reduced nitric oxide bioavailability and an increased in contractile prostaglandins levels as a consequence of endothelial damage. Moreover, the endothelium-relaxation reactivity of corpus cavernosum was attenuated in OG associated to the oxidative stress. Thus, it was provided a model for advances in sexual dysfunction field and drug discovery for ED treatment.

Acute Aerobic Swimming Exercise Induces Distinct Effects in the Contractile Reactivity of Rat Ileum to KCl and Carbachol.

Aerobic exercise promotes short-term physiological changes in the intestinal smooth muscle associated to the ischemia-reperfusion process; however, few studies have demonstrated its effect on the intestinal contractile function. Thus, this work describes our observations regarding the influence of acute aerobic swimming exercise in the contractile reactivity, oxidative stress, and morphology of rat ileum. Wistar rats were divided into sedentary (SED) and acutely exercised (EX-AC) groups. Animals were acclimated by 10, 10, and 30 min of swimming exercise in intercalated days 1 week before exercise. Then they were submitted to forced swimming for 1 h with a metal of 3% of their body weight attached to their body. Animals were euthanized immediately after the exercise section and the ileum was suspended in organ baths for monitoring isotonic contractions. The analysis of lipid peroxidation was performed in order to determinate the malondialdehyde (MDA) levels as a marker of oxidative stress, and intestinal smooth muscle morphology by histological staining. Cumulative concentration-response curves to KCl were altered in the EX-AC with an increase in both its efficacy and potency (E max = 153.2 ± 2.8%, EC 50 = 1.3 ± 0.1 × 10(-2) M) compared to the SED group (E max = 100%, EC 50 = 1.8 ± 0.1 × 10(-2) M). Interestingly, carbachol had its efficacy and potency reduced in the EX-AC (E max = 67.1 ± 1.4%, EC 50 = 9.8 ± 1.4 × 10(-7) M) compared to the SED group (E max = 100%, EC 50 = 2.0 ± 0.2 × 10(-7) M). The exercise did not alter the MDA levels in the ileum (5.4 ± 0.6 µ mol/mL) in the EX-AC compared to the SED group (8.4 ± 1.7 µ mol/mL). Moreover, neither the circular nor the longitudinal smooth muscle layers thickness were modified by the exercise (66.2 ± 6.0 and 40.2 ± 2.6 µm, respectively), compared to the SED group (61.6 ± 6.4 and 34.8 ± 3.7 µm, respectively). Therefore, the ileum sensitivity to contractile agents is differentially altered by the acute aerobic swimming exercise, without affecting the oxidative stress and the morphology of ileum smooth muscle.

Involvement of ß adrenergic receptors in spasmolytic effect of caulerpine on guinea pig ileum.

Previously, we demonstrated that caulerpine has spasmolytic effect on guinea pig ileum. The aim of this study was to investigate pathways of its spasmolytic action. We test caulerpine against phasic contractions induced by carbachol in the circular layer of guinea pig ileum and this alkaloid did not inhibit these contractions, indicating that caulerpine did not interfering with the mobilisation of Ca2+ from intracellular stores. Additionally, the spasmolytic effect of caulerpine did not involve K+ channels. Furthermore, we observed that α2-adrenergic receptors were not involved in the spasmolytic effect of caulerpine, since the relaxation curve induced by caulerpine was not shifted in the presence of yohimbine (α2-adrenergic antagonist). However, in the presence of propranolol (ß-adrenergic antagonist), the relaxation curve induced by caulerpine was right-shifted, resulting in a fivefold increase in EC50. Thus, a possible mechanism for the spasmolytic action of caulerpine is the activation of ß-adrenergic receptors.

Croton grewioides Baill. (Euphorbiaceae) Shows Antidiarrheal Activity in Mice.

UNLABELLED: Based on chemotaxonomy, we decided to investigate the possible antidiarrheal activity in mice of a crude ethanolic extract obtained from aerial parts of Croton grewioides (CG-EtOH). We tested for any possible toxicity in rat erythrocytes and acute toxicity in mice. Antidiarrheal activity was assessed by determining the effect of CG-EtOH on defecation frequency, liquid stool, intestinal motility and intestinal fluid accumulation. CG-EtOH showed no in vitro cytotoxicity and was not orally lethal. In contrast, the extract given intraperitoneally (at 2000 mg/kg) was lethal, but only in females. CG-EtOH produced a significant and equipotent antidiarrheal activity, both in defecation frequency (ED50 = 106.0 ± 8.1 mg/kg) and liquid stools (ED50 = 105.0 ± 9.2 mg/kg). However, CG-EtOH (125 mg/kg) decreased intestinal motility by only 22.7% ± 4.4%. Moreover, extract markedly inhibited the castor oil-induced intestinal contents (ED50 = 34.6 ± 5.4 mg/kg). We thus conclude that CG-EtOH is not orally lethal and contains active principles with antidiarrheal activity, and this effect seems to involve mostly changes in intestinal secretion. SUMMARY: CG-EtOH showed no in vitro cytotoxicity and was not orally lethal. In contrast, the extract given intraperitoneally (at 2000 mg/kg) was lethal, but only in females.CG-EtOH probably contains active metabolites with antidiarrheal activity.CG-EtOH reduced the frequency and number of liquid stools.Metabolites presents in the CG-EtOH act mainly by reducing intestinal fluid and, to a lesser extent, reducing intestinal motility. Abbreviations Used: CG-EtOH: crude ethanolic extract obtained from the aerial parts of C. grewioides; WHO: World Health Organization; ED50: dose of a drug that produces 50% of its maximum effect; Emax: maximum effect.

Chronic aerobic swimming exercise promotes functional and morphological changes in rat ileum.

Several studies have reported the gastrointestinal (GI) effects promoted by the physical exercise. Thus, we aimed to evaluate the influence of swimming exercise on the contractile reactivity, lipid peroxidation and morphology of rat ileum. Wistar rats were divided into sedentary (SED) and groups exercised for two (EX2), four (EX4), six (EX6) or eight (EX8) weeks, 5 days/week. Animals were killed; the ileum was removed and suspended in organ baths where the isotonic contractions were recorded. Lipid peroxidation was evaluated by MDA (malondialdehyde) measurement with TBARS (thiobarbituric acid reactive substances) assay and morphology by histological staining. Cumulative concentration-response curves to KCl were attenuated, as the Emax values were changed from 100% (SED) to 63.1±3.9 (EX2), 48.8±3.8 (EX4), 19.4±1.8 (EX6) and 59.4±2.8% (EX8). Similarly, cumulative concentration-response curves to carbamylcholine hydrochloride (CCh) were attenuated, as the Emax values were changed from 100% (SED) to 74.1±5.4 (EX2), 75.9±5.2 (EX4) and 62.9±4.6 (EX6), but not in the EX8 (89.7±3.4%). However, CCh potency was increased in this latter, as the EC50 was altered from 1.0±0.1×10(-6) (SED) to 2.1±0.4×10(-7) (EX8). MDA concentration was altered only in EX4 (44.3±4.4) compared with SED (20.6±3.6 µmol/l). Circular layer was reduced in SED when compared with the exercised groups. Conversely, longitudinal layer was increased. In conclusion, chronic swimming exercise reduces the ileum contraction, equilibrates the oxidative damage and promotes changes in tissue size to establish an adaptation to the exercise.

Antidiarrheal activity of Solanum asterophorum in mice

Several species of Solanum are used in folk medicine to treat diarrhea. Therefore, the aim of this study was to investigate and compare possible antidiarrheal activity of methanol extracts from roots (Sast-MeOH R) and leaves (Sast-MeOH L) of Solanum asterophorum Mart., Solanaceae, in mice. Sast-MeOH R was shown to significantly and dose-relatedly inhibit the frequency of both solid (ED50 309.6±28.5 mg/kg) and liquid (ED50 152.1±32.5 mg/kg) stools. Conversely, Sast-MeOH L significantly inhibited solid stool frequency only when dosed at 500 and 750 mg/kg (48.7±7.4 and 42.3±9.8 percent, respectively), but also significantly and dose-relatedly inhibited liquid stools (ED50 268.4±35.2 mg/kg). Thus, Sast-MeOH R was twice as potent as Sast-MeOH L in diarrhea inhibition. Neither extracts (when dosed up to 500 mg/kg) inhibited intestinal transit. However, both extracts significantly and dose-relatedly inhibited intestinal fluids, and Sast-MeOH R (ED50 38.3±10.4 mg/kg) was again twice as potent as Sast-MeOH L (ED50 78.6±6.4 mg/kg). Results suggest that antidiarrheal effects of Sast-MeOH R and Sast-MeOH L involve changes on intestinal secretion. In addition, active metabolites with antidiarrheal activity may be more concentrated in the roots of this species. However further studies are needed to elucidate the action mechanism involved in this activity.