Novel p38 Mitogen-Activated Protein Kinase Inhibitor Reverses Hypoxia-Induced Pulmonary Arterial Hypertension in Rats.

Mitogen-activated protein kinase (MAPK) signaling is strongly implicated in cardiovascular remodeling in pulmonary hypertension (PH) and right ventricle (RV) failure. The effects of a newly designed p38 inhibitor, LASSBio-1824, were investigated in experimentally induced PH. Male Wistar rats were exposed to hypoxia and SU5416 (SuHx), and normoxic rats were used as controls. Oral treatment was performed for 14 days with either vehicle or LASSBio-1824 (50 mg/kg). Pulmonary vascular resistance and RV structure and function were assessed by echocardiography and catheterization. Histological, immunohistochemical and Western blot analysis of lung and RV were performed to investigate cardiovascular remodeling and inflammation. Treatment with LASSBio-1824 normalized vascular resistance by attenuating vessel muscularization and endothelial dysfunction. In the heart, treatment decreased RV systolic pressure, hypertrophy and collagen content, improving cardiac function. Protein content of TNF-α, iNOS, phosphorylated p38 and caspase-3 were reduced both in lung vessels and RV tissues after treatment and a reduced activation of transcription factor c-fos was found in cardiomyocytes of treated SuHx rats. Therefore, LASSBio-1824 represents a potential candidate for remodeling-targeted treatment of PH.

Antinociceptive Effect of Lodenafil Carbonate in Rodent Models of Inflammatory Pain and Spinal Nerve Ligation-Induced Neuropathic Pain.

INTRODUCTION: New therapeutic alternatives for pain relief include the use of phosphodiesterase-5 (PDE5) inhibitors, which could prevent the transmission of painful stimuli by neuron hyperpolarization via nitric oxide (NO)/cyclic 3',5'-guanosine monophosphate (cGMP) pathway. The present work investigated the antinociceptive activity of a new PDE5 inhibitor, lodenafil carbonate, in inflammatory and neuropathic pain models. METHODS AND RESULTS: Although no effect was detected on neurogenic phase of formalin test in mice, oral administration of lodenafil carbonate dose-dependently reduced reactivity in the inflammatory phase (200.6 ± 39.1 to 81.9 ± 18.8 s at 10 µmol/kg, p= 0.0172) and this effect was totally blocked by NO synthase inhibitor, L-Nω-nitroarginine methyl ester (L-NAME). Lodenafil carbonate (10 µmol/kg p.o.) significantly reduced nociceptive response as demonstrated by increased paw withdrawal latency to thermal stimulus (from 6.8 ± 0.7 to 10.6 ± 1.3 s, p= 0.0006) and paw withdrawal threshold to compressive force (from 188.0 ± 14.0 to 252.5 ± 5.3 g, p<0.0001) in carrageenan-induced paw inflammation model. In a spinal nerve ligation-induced neuropathic pain, oral lodenafil carbonate (10 µmol/kg) also reversed thermal hyperalgesia and mechanical allodynia by increasing paw withdrawal latency from 17.9 ± 1.5 to 22.8 ± 1.9 s (p= 0.0062) and paw withdrawal threshold from 26.0 ± 2.8 to 41.4 ± 2.9 g (p= 0.0196). These effects were reinforced by the reduced GFAP (3.4 ± 0.5 to 1.4 ± 0.3%, p= 0.0253) and TNF-alpha (1.1 ± 0.1 to 0.4 ± 0.1%, p= 0.0111) stained area densities as detected by immunofluorescence in ipsilateral dorsal horns. CONCLUSION: Lodenafil carbonate demonstrates important analgesic activity by promoting presynaptic hyperpolarization and preventing neuroplastic changes, which may perpetuate chronic pain, thus representing a potential treatment for neuropathic pain.

Therapeutic Benefit of the Association of Lodenafil with Mesenchymal Stem Cells on Hypoxia-induced Pulmonary Hypertension in Rats.

Pulmonary arterial hypertension (PAH) is characterized by the remodeling of pulmonary arteries, with an increased pulmonary arterial pressure and right ventricle (RV) overload. This work investigated the benefit of the association of human umbilical cord mesenchymal stem cells (hMSCs) with lodenafil, a phosphodiesterase-5 inhibitor, in an animal model of PAH. Male Wistar rats were exposed to hypoxia (10% O2) for three weeks plus a weekly i.p. injection of a vascular endothelial growth factor receptor inhibitor (SU5416, 20 mg/kg, SuHx). After confirmation of PAH, animals received intravenous injection of 5.105 hMSCs or vehicle, followed by oral treatment with lodenafil carbonate (10 mg/kg/day) for 14 days. The ratio between pulmonary artery acceleration time and RV ejection time reduced from 0.42 ± 0.01 (control) to 0.24 ± 0.01 in the SuHx group, which was not altered by lodenafil alone but was recovered to 0.31 ± 0.01 when administered in association with hMSCs. RV afterload was confirmed in the SuHx group with an increased RV systolic pressure (mmHg) of 52.1 ± 8.8 normalized to 29.6 ± 2.2 after treatment with the association. Treatment with hMSCs + lodenafil reversed RV hypertrophy, fibrosis and interstitial cell infiltration in the SuHx group. Combined therapy of lodenafil and hMSCs may be a strategy for PAH treatment.

New Benzofuran N-Acylhydrazone Reduces Cardiovascular Dysfunction in Obese Rats by Blocking TNF-Alpha Synthesis.

INTRODUCTION: Diabetic obese patients are susceptible to the development of cardiovascular disease, including hypertension and cardiac dysfunction culminating in diabetic cardiomyopathy (DC), which represents a life-threatening health problem with increased rates of morbidity and mortality. The aim of the study is to characterize the effects of a new benzofuran N-acylhydrazone compound, LASSBio-2090, on metabolic and cardiovascular alterations in Zucker diabetic fatty (ZDF) rats presenting DC. METHODS: Male non-diabetic lean Zucker rats (ZL) and ZDF rats treated with vehicle (dimethylsulfoxide) or LASSBio-2090 were used in this study. Metabolic parameters, cardiovascular function, left ventricle histology and inflammatory protein expression were analyzed in the experimental groups. RESULTS: LASSBio-2090 administration in ZDF rats reduced glucose levels to 85.0 ± 1.7 mg/dL (p < 0.05). LASSBio-2090 also lowered the cholesterol and triglyceride levels from 177.8 ± 31.2 to 104.8 ± 5.3 mg/dL and from 123.0 ± 11.4 to 90.9 ± 4.8 mg/dL, respectively, in obese diabetic rats (p < 0.05). LASSBio-2090 normalized plasma insulin, insulin sensitivity and endothelial function in aortas from diabetic animals (p < 0.05). It also enhanced systolic and diastolic left-ventricular function and reverted myocardial remodeling by blocking the threefold elevation of TNF-α levels in hearts from ZDF rats. CONCLUSION: LASSBio-2090 alleviates metabolic disturbance and cardiomyopathy in an obese and diabetic rat model, thus representing a novel strategy for the treatment of cardiovascular complications in obesity-associated type 2 diabetes mellitus.

Antinociception induced by a novel α2A adrenergic receptor agonist in rodents acute and chronic pain models.

The mechanisms and antinociceptive effects of a novel α2A adrenoceptor agonist, 3-(2-chloro-6-fluorobenzil)-imidazolinide-2,4-dione (PT-31) were investigated using animal models of acute and chronic pain. The effects of PT-31 on pain responses were examined using hot plate and formalin tests in mice and spinal nerve ligation (SNL)-induced hyperalgesia in rats. The effects of antagonists acting on α adrenoceptor were assessed to investigate the interaction of these pathways upon PT-31 induced antinociception. PT-31 effects on motor activity/skills and on hemodynamic parameters were also evaluated. PT-31 had dose-dependent antinociception effects on hot-plate and formalin-injection induced pain responses. Thermal hyperalgesia and mechanical allodynia were reduced following a 7 d treatment with PT-31 (1, 5, and 10mg/kg/d, p.o.), and those effects were attenuated by yohimbine (5mg/kg), atropine (2mg/kg), L-nitro arginine methyl ester (L-NAME; 30mg/kg), or naloxone (2mg/kg). In contrast to clonidine, PT-31 did not have locomotor or hemodynamic effects in rats. The present results suggest that PT-31 represents a candidate for pain treatment with advantages over clonidine, namely no locomotor or hemodynamic impairments.

The Hypnotic, Anxiolytic, and Antinociceptive Profile of a Novel µ-Opioid Agonist.

5'-4-Alkyl/aryl-1H-1,2,3-triazole derivatives PILAB 1-12 were synthesized and a pharmacological screening of these derivatives was performed to identify a possible effect on the Central Nervous System (CNS) and to explore the associated mechanisms of action. The mice received a peritoneal injection (100 µmol/kg) of each of the 12 PILAB derivatives 10 min prior to the injection of pentobarbital and the mean hypnosis times were recorded. The mean hypnosis time increased for the mice treated with PILAB 8, which was prevented when mice were administered CTOP, a µ-opioid antagonist. Locomotor and motor activities were not affected by PILAB 8. The anxiolytic effect of PILAB 8 was evaluated next in an elevated-plus maze apparatus. PILAB 8 and midazolam increased a percentage of entries and spent time in the open arms of the apparatus compared with the control group. Conversely, a decrease in the percentages of entries and time spent in the closed arms were observed. Pretreatment with naloxone, a non-specific opioid antagonist, prior to administration of PILAB 8 exhibited a reverted anxiolytic effect. PILAB 8 exhibited antinociceptive activity in the hot plate test, and reduced reactivity to formalin in the neurogenic and the inflammatory phases. These data suggest that PILAB 8 can activate µ-opioid receptors to provoke antinociceptive and anti-inflammatory effects in mice.

Synthesis, solubility, plasma stability, and pharmacological evaluation of novel sulfonylhydrazones designed as anti-diabetic agents.

Neuropathy is a serious complication of diabetes that has a significant socioeconomic impact, since it frequently demands high levels of health care consumption and compromises labor productivity. Recently, LASSBio-1471 (3) was demonstrated to improve oral glucose tolerance, reduce blood glucose levels, and display an anti-neuropathy effect in a murine streptozotocin-induced diabetes model. In the present work, we describe the design, synthesis, solubility, plasma stability, and pharmacological evaluation of novel sulfonylhydrazone derivatives (referred to herein as compounds 4-9), which were designed by molecular modification based on the structure of the prototype LASSBio-1471 (3). Among the compounds tested, better plasma stability was observed with 4, 5, and 9 in comparison to compounds 6, 7, and 8. LASSBio-1773 (7), promoted not only hypoglycemic activity but also the reduction of thermal hyperalgesia and mechanical allodynia in a murine model of streptozotocin-induced diabetic neuropathic pain.

Treatment with Adenosine Receptor Agonist Ameliorates Pain Induced by Acute and Chronic Inflammation.

Rheumatoid arthritis is an inflammatory autoimmune condition, and tumor necrosis factor-α (TNF-α) plays an important role in its pathophysiology. In vitro, (E)-N'-(3,4-dimethoxybenzylidene)-N-methylbenzohydrazide (LASSBio-1359) has exhibited anti-TNF-α properties, and in vivo these effects are mediated via activation of adenosine receptor. This work investigates the antinociceptive action of LASSBio-1359 in murine models of acute and chronic inflammatory pain. Male mice received an intraperitoneal injection of LASSBio-1359 and then were evaluated in formalin- and carrageenan-induced paw edema assays. Complete Freund's adjuvant (CFA) was used to induce a mouse model of monoarthritis. These mice were treated with LASSBio-1359 by oral gavage to evaluate thermal and mechanical hyperalgesia. TNF-α and inducible nitric oxide synthase (iNOS) expression as well as histologic features were analyzed. The time of reactivity to formalin in the neurogenic phase was reduced from 56.3 ± 6.0 seconds to 32.7 ± 2.2 seconds and 23.8 ± 2.6 seconds after treatment with LASSBio-1359 at doses of 10 mg/kg and 20 mg/kg, respectively. A reversal of the antinociceptive action of LASSBio-1359 was observed in the inflammatory phase after treatment with ZM 241385 [4-(2-[7-amino-2-(2-furly)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol], an adenosine A2A antagonist. Carrageenan-induced thermal and mechanical hyperalgesia were reduced after treatment with LASSBio-1359. Similarly, CFA-induced thermal and mechanical hyperalgesia were reduced after treatment with LASSBio-1359 (25 and 50 mg/kg). Levels of TNF-α and iNOS expression increased in the monoarthritis model and were normalized in animals treated with LASSBio-1359, which was also associated with beneficial effects in the histologic analysis. These results suggest that LASSBio-1359 represents an alternative treatment of monoarthritis.

Novel agonist of adenosine receptor induces relaxation of corpus cavernosum in guinea pigs: an in vitro and in vivo study.

OBJECTIVE: To test the relaxation effect of a new adenosine receptor agonist N-acylhydrazone derivative, 3,4-dimethoxyphenyl-N-methyl-benzoylhydrazide (LASSBio-1359), on in vitro and in vivo preparation of corpus cavernosum (CC), and its interaction with type-5 phosphodiesterase enzyme inhibitor, sildenafil. METHODS: For in vitro study, an increasing concentration of LASSBio-1359 was added in the solution at the plateau isometric tension recording of isolated guinea pig CC induced by phenylephrine (30 µM). Concentration-response curve was repeated in the presence of A2A receptor antagonist, ZM 241385 (10 µM). Sildenafil-induced CC relaxing effect was compared with that of LASSBio-1359. Isobolographic analysis was performed to identify possible synergistic interaction between LASSBio-1359 and sildenafil. For in vivo study, blood pressure response in the CC of guinea pig was measured after administration of LASSBio-1359 (10 mg/kg intravenously) or sildenafil (10 mg/kg intravenously). RESULTS: LASSBio-1359 caused relaxation of phenylephrine-induced contraction of isolated CC in a concentration-dependent manner (IC50 = 10.1 ± 1.8 µM), which was shifted to the right in the presence of ZM 241385 (IC50 = 27.1 ± 1.4 µM; P <.05). Isobolographic analysis showed synergistic interaction between LASSBio-1359 and sildenafil. As sildenafil, LASSBio-1359 increased blood pressure oscillation in the CC confirming its systemic efficacy. CONCLUSION: CC relaxing effects induced by the adenosine A2A receptor agonist, LASSBio-1359, demonstrated in vitro and in vivo experimental protocols, represent a promise therapeutic option for the treatment of erectile dysfunction. Synergistic interaction of LASSBio-1359 with sildenafil suggests a combined use to reach a higher population of patients with erectile dysfunction.

Novel orally active analgesic and anti-inflammatory cyclohexyl-N-acylhydrazone derivatives.

The N-acylhydrazone (NAH) moiety is considered a privileged structure, being present in many compounds with diverse pharmacological activities. Among the activities attributed to NAH derivatives anti-inflammatory and analgesic ones are recurrent. As part of a research program aiming at the design of new analgesic and anti-inflammatory lead-candidates, a series of cyclohexyl-N-acylhydrazones 10-26 were structurally designed from molecular modification on the prototype LASSBio-294, representing a new class of cycloalkyl analogues. Compounds 10-26 and their conformationally restricted analogue 9 were synthetized and evaluated as analgesic and anti-inflammatory agents in classical pharmacologic protocols. The cyclohexyl-N-acylhydrazones 10-26 and the cyclohexenyl analogue 9 showed great anti-inflammatory and/or analgesic activities, but compound 13 stood out as a new prototype to treat acute and chronic painful states due to its important analgesic activity in a neuropathic pain model.

Laceration in rat gastrocnemius. Following-up muscle repairing by ultrasound biomicroscopy (in vivo), contractility test (ex vivo) and histopathology.

PURPOSE: Implement a laceration protocol of the rat lateral gastrocnemius (LG) and following-up its repair with ultrasound biomicroscopy (UBM), contractility tests and histology. METHODS: Sixty-three male Wistar rats were distributed into two groups. One, with sub-groups GI, GII and GIII (n=12), each containing right LG lacerated (n=6), control and sham (n=3) animals. LG muscles in GI, GII and GIII were inspected by UBM (40 MHz) immediately after, 14 and 28 days post-surgery and thereafter excised with four (GI), 14 (GII) and 28 (GIII) days post-surgery for histology. Animals in second group were distributed into right LG lacerated and control sub-groups. LG muscles in lacerated sub-group were submitted to contractility tests at four (n=8), 14 (n=8) and 28 (n=8) days post-surgery, while in the control sub-group (n=5) were submitted to contractility tests along the course of the experiments. RESULTS: Descriptive findings agreed between the lesion model, muscle repair, UBM images and histology. Contractility results for right LG were different (p<0.05) between control and injured muscle with four and 14 days post-surgery, at tetanic stimulating frequencies (50 and 70 Hz). CONCLUSION: A laceration protocol of the lateral gastrocnemius was implemented and ultrasound biomicroscopy, contractility and histology findings agreed regarding the following-up of injured muscle repair.

Laceration in rat gastrocnemius. Following-up muscle repairing by ultrasound biomicroscopy (in vivo), contractility test (ex vivo) and histopathology

PURPOSE: Implement a laceration protocol of the rat lateral gastrocnemius (LG) and following-up its repair with ultrasound biomicroscopy (UBM), contractility tests and histology. METHODS: Sixty-three male Wistar rats were distributed into two groups. One, with sub-groups GI, GII and GIII (n=12), each containing right LG lacerated (n=6), control and sham (n=3) animals. LG muscles in GI, GII and GIII were inspected by UBM (40 MHz) immediately after, 14 and 28 days post-surgery and thereafter excised with four (GI), 14 (GII) and 28 (GIII) days post-surgery for histology. Animals in second group were distributed into right LG lacerated and control sub-groups. LG muscles in lacerated sub-group were submitted to contractility tests at four (n=8), 14 (n=8) and 28 (n=8) days post-surgery, while in the control sub-group (n=5) were submitted to contractility tests along the course of the experiments. RESULTS: Descriptive findings agreed between the lesion model, muscle repair, UBM images and histology. Contractility results for right LG were different (p<0.05) between control and injured muscle with four and 14 days post-surgery, at tetanic stimulating frequencies (50 and 70 Hz). CONCLUSION: A laceration protocol of the lateral gastrocnemius was implemented and ultrasound biomicroscopy, contractility and histology findings agreed regarding the following-up of injured muscle repair. .

Oral treatment with Euterpe oleracea Mart. (açaí) extract improves cardiac dysfunction and exercise intolerance in rats subjected to myocardial infarction.

BACKGROUND: This study was designed to evaluate the cardioprotective effects of Euterpe oleracea Mart., popularly known as "açaí", on rats subjected to myocardial infarction (MI). METHODS: Hydroalcoholic extracts of açaí were obtained from a decoction of the seeds. Two male Wistar rat groups were delineated: 1) the sham-operated group (control, n = 6), with no surgical amendment, and 2) the MI group (n = 12), in which the anterior descendent coronary artery was occluded during surgery. MI group was divided into two subgroups, in which rats were either treated with hydroalcoholic extract of Euterpe oleracea seeds (100 mg/kg/day p.o.) or received no treatment. Treatment began on the day of surgery, and lasted 4 weeks. Subsequently, rats were subject to an exercise test protocol, hemodynamic evaluation, and histological analysis of the left ventricle. Groups were compared using one-way analysis of variance (ANOVA), followed by Dunnett's test. RESULTS: The total running distance of sham rats was 1339.0 ± 276.6 m, MI rats was 177.6 ± 15.8 m (P < 0.05), and MI-açaí rats was 969.9 ± 362.2 m. Systolic arterial pressure was significantly decreased in MI rats (86.88 ± 4.62 mmHg) compared to sham rats (115.30 ± 7.24 mmHg; P < 0.05). Açaí treatment prevented a reduction in systolic arterial pressure (130.00 ± 8.16 mmHg) compared to MI rats (P < 0.05). Left ventricular (LV) end-diastolic pressure was significantly augmented in MI rats (17.62 ± 1.21 mmHg) compared to sham rats (4.15 ± 1.60 mmHg; P < 0.05), but was 3.69 ± 2.69 mmHg in açaí-treated rats (P < 0.05 vs. MI). The LV relaxation rate (-dp/dt) was reduced in MI rats compared to the sham group, whereas açaí treatment prevented this reduction. Açaí treatment prevented cardiac hypertrophy and LV fibrosis in MI rats. CONCLUSIONS: Euterpe oleracea treatment of MI rats prevented the development of exercise intolerance, cardiac hypertrophy, fibrosis, and dysfunction.

Vasodilator and antihypertensive effects of a novel N-acylhydrazone derivative mediated by the inhibition of L-type Ca²âº channels.

New bioactive N-acylhydrazone derivatives synthesized from safrole previously have been found to promote intense vasodilation and antihypertensive activity. In this study, we describe the synthesis and the cardiovascular effects of the new N-acylhydrazone derivative (E)-N-methyl-N'-(thiophen-3-ylmethylene)benzo[d][1,3]dioxole-5-carbohydrazide (LASSBio-1289). Thoracic aorta and left papillary muscles from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were prepared for isometric tension recording. LASSBio-1289 promoted relaxation of endothelium-intact and denuded aortic rings with respective pIC50 (-log IC50) values of 5.07 ± 0.09 and 4.26 ± 0.09 (P < 0.001) for WKY rats and 5.43 ± 0.05 and 5.58 ± 0.07 (P > 0.05) for SHR. The vasodilator activity of LASSBio-1289 was increased in the KCl-contracted aorta. LASSBio-1289 attenuated the contracture elicited by Ca(2+) in depolarized aorta from both WKY rats and SHR. In endothelium-intact aorta from WKY rats, LASSBio-1289-induced relaxation was unchanged after incubation with propranolol, ZM 241385, atropine, diphenhydramine, and HOE140, but was significantly reduced by L-NAME and ODQ. LASSBio-1289 decreased papillary muscles contractility only at concentrations above 200 µm. Acute intravenous injection of LASSBio-1289 (3 mg/kg) produced a significant hypotensive response in SHR but not in WKY rats, suggesting its antihypertensive profile. The antihypertensive effect was also observed in SHR during 14 days of intraperitoneal and oral administration. In conclusion, our data demonstrated that LASSBio-1289 induces both endothelium-independent vasorelaxation involving the inhibition of Ca(2+) influx through L-type Ca(2+) channels in aorta from WKY rats and SHR, and endothelium-dependent relaxation mediated by the NO/cyclic GMP pathway in WKY rats.

N-acylhydrazone improves exercise intolerance in rats submitted to myocardial infarction by the recovery of calcium homeostasis in skeletal muscle.

AIMS: This work investigated the effects of 3,4-methylenedioxybenzoyl-2-thienylhydrazone (LASSBio-294) treatment on the contractile response of soleus (SOL) muscle from rats submitted to myocardial infarction (MI). MAIN METHODS: Following coronary artery ligation, LASSBio-294 (2mg/kg, i.p.) or vehicle was administrated once daily for 4 weeks. KEY FINDINGS: The run time to fatigue for sham rats was 17.9 ±2.6 min, and it was reduced to 3.3 ± 0.8 min (P<0.05) in MI rats. In MI rats treated with LASSBio-294, the time to fatigue was 15.1 ± 3.6 min. During the contractile test, SOL muscles from sham rats showed a response of 7.12 ± 0.54N/cm(2) at 60 Hz, which was decreased to 5.45 ± 0.49 N/cm(2) (P<0.05) in MI rats. The contractility of SOL muscles from the MI-LASSBio-294 group was increased to 9.01 ± 0.65N/cm(2). At 16 mM caffeine, the contractility was reduced from 2.31 ± 0.33 to 1.60 ± 0.21 N/cm(2) (P<0.05) in the MI group. In SOL muscles from MI-LASSBio-294 rats, the caffeine response was increased to 2.62 ± 0.33 N/cm(2). Moreover, SERCA2a expression in SOL muscles was decreased by 0.31-fold (31%) in the MI group compared to the Sham group (P<0.05). In the MI-LASSBio-294 group, it was increased by 1.53-fold (153%) compared to the MI group (P<0.05). Meanwhile, the nuclear density in SOL muscles was increased in the MI group compared to the Sham group. Treatment with LASSBio-294 prevented this enhancement of cellular infiltrate. SIGNIFICANCE: LASSBio-294 treatment prevented the development of muscular fatigue and improved exercise intolerance in rats submitted to MI.

Vasodilator activity of the essential oil from aerial parts of Pectis brevipedunculata and its main constituent citral in rat aorta.

The essential oil of Pectis brevipedunculata (EOPB), a Brazilian ornamental aromatic grass, is characterized by its high content of citral (81.9%: neral 32.7% and geranial 49.2%), limonene (4.7%) and α-pinene (3.4%). Vasodilation induced by EOPB and isolated citral was investigated in pre-contracted vascular smooth muscle, using thoracic aorta from Wistar Kyoto (WKY) rats which was prepared for isometric tension recording. EOPB promoted intense relaxation of endothelium-intact and denuded aortic rings with the concentration to induce 50% of the maximal relaxation (IC50) of 0.044% ± 0.006% and 0.093% ± 0.015% (p < 0.05), respectively. The IC50 values for citral in endothelium-intact and denuded rings were 0.024% ± 0.004% and 0.021% ± 0.004%, respectively (p > 0.05). In endothelium-intact aorta, EOPB-induced vasorelaxation was significantly reduced by L-NAME, a nitric oxide synthase inhibitor. The vasodilator activity of citral was increased in the KCl-contracted aorta and citral attenuated the contracture elicited by Ca2+ in depolarized aorta. EOPB and citral elicited vasorelaxation on thoracic aorta by affecting the NO/cyclic GMP pathway and the calcium influx through voltage-dependent L-type Ca2+ channels, respectively.

A novel Ca2+ channel antagonist reverses cardiac hypertrophy and pulmonary arteriolar remodeling in experimental pulmonary hypertension.

This work investigates the actions of LASSBio-1289, (E)-N-methyl-N'-(thiophen-3-methylene)benzo[d][1,3]dioxole-5-carbohydrazide, on monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats. Two weeks following the MCT injection, LASSBio-1289 (50 or 75mg/kg, p.o.) or vehicle was administrated once daily for 14 days. LASSBio-1289 (75 mg/kg) treatment caused a significant decrease in right ventricular systolic pressure (31.89±0.82 mmHg) compared to the MCT-vehicle group (52.74±6.19 mmHg; P<0.05). Oral treatment with LASSBio-1289 (50 or 75 mg/kg) effectively decreased pulmonary artery diameter and right ventricle (RV) area, assessed by echocardiography. LASSBio-1289 (75 mg/kg) reduced RV area (10.00±0.58 mm(2)) compared to the MCT-vehicle group (20.50±1.44 mm(2); P<0.05). LASSBio-1289 (75 mg/kg) also partially recovered the pulmonary artery acceleration time in MCT-treated rats. Oral treatment with LASSBio-1289 (50mg/kg) decreased the pulmonary arteriolar wall thickness (68.57±2.21%) compared to the MCT-vehicle group (81.07±1.92%; P<0.05). In experiments with isolated pulmonary arteries, the concentration of LASSBio-1289 necessary to produce 50% relaxation in the phenylephrine- or KCl-induced contraction was 27.31±6.94 and 2.72±0.99 µM, respectively, P<0.05. In the presence of LASSBio-1289 (50 µM), the maximal contraction induced by 10mM CaCl2 was reduced to 36.00±8.28% of the maximal contraction of the control curve (P<0.05). LASSBio-1289 was effective in attenuating MCT-induced PAH in rats, and its beneficial effects were likely mediated by the inhibition of extracellular Ca(2+) influx through L-type voltage-gated Ca(2+) channels in the pulmonary artery.

Antihypertensive profile of 2-thienyl-3,4-methylenedioxybenzoylhydrazone is mediated by activation of the A2A adenosine receptor.

Several N-acylhydrazone derivatives synthesized from safrole have been found to promote intense vasodilation and antihypertensive activity. The present work describes the synthesis and antihypertensive profile of 2-thienyl-3,4-methylenedioxybenzoylhydrazone (LASSBio-1027), a new analogue of the lead compound 3,4-methylenedioxybenzoyl-2-thienylhydrazone. Thoracic aortas from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were prepared for isometric tension recording. Noninvasive blood pressure measurements were made during 14 days of intraperitoneal (10 mg/kg) or oral (20 mg/kg) administration of LASSBio-1027. LASSBio-1027 exhibited partially endothelium-dependent vasorelaxant activity, which was attenuated in the presence of l-NAME, glibenclamide, or ZM 241385. LASSBio-1027 exhibited an antihypertensive effect in SHR during 14 days of intraperitoneal or oral administration, but did not induce a hypotensive effect in normotensive WKY rats. LASSBio-1027-induced vascular relaxation of aortas from WKY rats was mediated by the activation of A(2A) adenosine receptors. Docking studies and binding assays suggested that LASSBio-1027 has affinity for A(2A) and A(3) adenosine receptors. This new N-acylhydrazone derivative represents a potential strategy for the treatment of arterial hypertension.

Benzenesulfonamide attenuates monocrotaline-induced pulmonary arterial hypertension in a rat model.

In this study, we examined the effects of LASSBio-965 (N-[2-(3,4-dimethoxyphenyl) ethyl]-benzenesulfonamide), a compound designed as a simplified structure of a non-selective phosphodiesterase 4 inhibitor, on vascular smooth muscle in vitro as well as in a rat model of monocrotaline (MCT)-induced pulmonary arterial hypertension. LASSBio-965 (50 mg/kg) treatment caused a significant decrease in right systolic ventricular pressure (32.47 ± 3.09 mmHg) compared to the MCT-vehicle group (51.88 ± 3.23 mmHg; P<0.05) and in the ratio of right ventricular weight to left ventricular weight plus septum (0.42 ± 0.03 g compared to 0.59 ± 0.06 g, respectively; MCT-vehicle group; P<0.05). LASSBio-965 induced a concentration-dependent relaxation of rat aortic rings, which was decreased by mechanical removal of the endothelium. Milrinone, rolipram, and sildenafil reduced the maximum relaxation (100%) to 22.4 ± 5.8, 69.5 ± 5.6 and 80.1 ± 10.7%, respectively (P<0.05). Maximum relaxation responses of aortic and pulmonary artery rings were decreased in the MCT-vehicle group (54.80 ± 5.69 and 35.87 ± 4.78, respectively) compared to the control (91.51 ± 4.79 and 54.32 ± 2.39, respectively) but improved with LASSBio-965 treatment (50mg/kg; 88.43 ± 4.54 and 59.36 ± 4.83, respectively). These results indicate that LASSBio-965 can attenuate the pulmonary arterial hypertension in an animal model most likely through the nonselective inhibition of phosphodiesterases 3, 4, and 5.

Vasodilatory activity and antihypertensive profile mediated by inhibition of phosphodiesterase type 1 induced by a novel sulfonamide compound.

LASSBio-985 is a sulfonamide compound designed as a simplified structure of a nonselective phosphodiesterase type 4 (PDE-4) inhibitor that promotes vasodilatory activity in vitro. PDE are enzymes responsible for the hydrolysis of cyclic adenosine 3',5'- monophosphate and cyclic guanosine 3',5'-monophosphate. Five different isozymes of PDE are found in vascular smooth muscle (PDE1-PDE5). Aortic rings, with or without endothelium, from male normotensive and spontaneously hypertensive rats (SHR) were prepared for isometric tension recording. Blood pressure was measured in Wistar Kyoto (WKY) rats and SHR during intravenous infusion of LASSBio-985 (10 mg/kg/min) during 15 min. LASSBio-985 induced a concentration-dependent vasodilation in aortic rings from normotensive and SHR, which was almost completely inhibited in endothelium-denuded vessels. Vasodilatory activity was also reduced in endothelium-intact aortic rings that had been pretreated with N(ω)-nitro-L-arginine methyl ester hydrochloride (L-NAME), a nitric oxide synthase inhibitor and 1H-[1,2,4]oxadiazolod[4,3-a]quinoxalin-1-one (ODQ), a guanylate cyclase inhibitor. LASSBio-985-induced vasodilation was also inhibited by sildenafil (100 µm) and SQ 22536, a PDE5 inhibitor and adenylate cyclase inhibitor, respectively. To evaluate the involvement of some endothelial receptors, atropine, diphenhydramine, HOE 140, naloxone, propranolol, indomethacin, and wortmannin were tested, but none inhibited the effects of LASSBio-985. The residual effect observed on endothelium-denuded aortic rings was abolished by nicardipine, a voltage-sensitive-Ca(2+)-channel blocker. Intravenous infusion of LASSBio-985 (10 mg/kg/min) significantly reduced systolic and diastolic pressures in both WKY and SHR. LASSBio-985 is a compound with vasodilatory activity, which could be consequent to PDE1 inhibition and voltage-sensitive-Ca(2+)-channel blockade.