Warifteine, a bisbenzylisoquinoline alkaloid, induces relaxation by activating potassium channels in vascular myocytes.

The present study used functional and electrophysiological approaches to investigate the mechanisms by which warifteine, a bisbenzylisoquinoline alkaloid isolated from Cissampelos sympodialis Eichl., causes vasorelaxation of the rat thoracic aorta. Warifteine (1 pmol/L-10 µmol/L) induced concentration-dependent relaxation (pD(2) = 9.40 ± 0.06; n = 5) of endothelium-intact aortic rings precontracted with noradrenaline (10-100 µmol/L). The relaxation effects were not attenuated by removal of the endothelium. Warifteine also induced the relaxation of prostaglandin F(2α) (1-10 mmol/L)-precontracted rings (pD(2) = 9.2 ± 0.2; n = 8). In contrast, the relaxant activity of warifteine was nearly abolished in high K(+) (80 mmol/L)-precontracted aortic rings. In preparations incubated with 20 mmol/L KCl or with the K(+) channel blockers tetraethylammonium (1, 3 and 5 mmol/L), iberiotoxin (20 nmol/L), 4-aminopyridine (1 mmol/L) or glibenclamide (10 µmol/L), the vasorelaxant activity of warifteine was markedly reduced. However, BaCl(2) (1 mmol/L) had no effect on the relaxant effects of warifteine. In vascular myocytes, warifteine (100 nmol/L) significantly increased whole-cell K(+) currents (at 70 mV). Under nominally Ca(2+) -free conditions, warifteine did not reduce extracellular Ca(2+) -induced contractions in rings precontracted with high K(+) or noradrenaline (100 µmol/L). Together, the results of the present study indicate that warifteine induces potent concentration-dependent relaxation in the rat aorta via an endothelium-independent mechanism that involves the activation of K(+) channels.

Vasorelaxation induced by amodiaquine in rat superior mesenteric arteries: in vivo and in vitro studies.

The aim of this study was to investigate the mechanisms underlying vasorelaxation induced by amodiaquine (AMQ) in rat superior mesenteric arteries. In normotensive, conscious rats, AMQ at 1-20 mg/kg i.v. produced hypotension and dose-dependent bradycardia. In mesenteric rings pre-contracted with phenylephrine (PHE) (10(-5) M), AMQ caused concentration-dependent relaxation [IC50 = (1.34 +/- 0.04) x 10(-5) M, Emax = 67.5 +/- 0.8%]. Vasorelaxation induced by AMQ was unaffected after removal of the endothelium (Emax = 66.9 +/- 0.3%, p > 0.05), and in the presence of ouabain (10(-4) M) (Emax = 65.4 +/- 1.9%, p > 0.05). In contrast, vasorelaxation evoked by AMQ was significantly inhibited after pre-treatments with 4-aminopyridine (10(-3) M), tetraethylammonium (10(-3) M) and glibenclamide (10(-5) M), blockers of voltage-dependent K+ (Kv), large and intermediate conductance Ca2+ -activated K+ (BK(Ca)) and K(ATP), channels, respectively. Additionally, AMQ reduced CaCl2-induced contractions in Ca2+ -free solution containing KCl, probably due to its non-selective opening of K+ channels or may be acting as Ca2+ -antagonist. Furthermore, AMQ did not interfere with Ca2+ release from intracellular stores mediated by either phenylephrine (10(-5) M) or caffeine (0.02 M). Collectively, these results provide functional evidence that AMQ-induced hypotensive and bradycardic effects may involve the opening of K+ channels sensitive to 4-aminopyridine, tetraethylammonium and glibenclamide or the blockade of extracellular Ca2+ influx.

Influência do grau de bipartição escrotal sobre parâmetros reprodutivos de caprinos / Influence of the scrotum bipartite on the reproductive parameters in goats

Avaliou-se a influência do grau de bipartição escrotal sobre os parâmetros reprodutivos em caprinos. Foram utilizados 30 animais, distribuídos em três grupos: Grupo I, animais que apresentavam escroto sem bipartição (n =10); Grupo II, animais com bipartição escrotal até 50 por cento do comprimento dos testículos (n=10); e Grupo III, caprinos com bipartição escrotal acima de 50 por cento do comprimento testicular (n=10). Os parâmetros avaliados foram peso corporal, perímetro escrotal, comprimento testicular, características físicas e morfológicas do sêmen, concentração plasmática de testosterona e libido dos animais, comparando caprinos com escroto bipartido e não bipartido. Os animais que apresentavam bipartição escrotal expressaram maior peso corporal e comprimento testicular, quando comparados com os animais do grupo sem escroto bipartido, sendo que estes apresentaram maior número de células espermáticas defeituosas. Conclui-se que a bipartição escrotal influencia positivamente alguns parâmetros biométricos bem como a qualidade do sêmen em caprinos.

The influence of scrotum division on the reproductive parameters in goats was evaluated. Thirty animals were divided into three groups of 10 animals each as follows. Group I: animals with simple scrotum (n=10); Group II: animals with 50 percent of scrotum bipartite (n=10); and Group III: animals with more than 50 percent of scrotum bipartite (n=10). It was evaluated: body weight, scrotum perimeter and the testicular length, the seminal characteristic, plasmatic concentration of testosterone, and the libido of the animals with different degrees of scrotum division. Animals with divided scrotum had higher weight and testicular length when compared with animals from the first group that had a higher percentage of spermatic defects. It is possible to conclude that there was a positive influence of scrotal bipartition on the biometric parameters and the sperm quality in goats.

Hypotensive and endothelium-independent vasorelaxant effects of methanolic extract from Curcuma longa L. in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Curcuma longa L. (CL) is a yellow rhizome that is used in African traditional medicine to treat palpitation, hypertension or other related blood circulation disorders. AIM OF THE STUDY: To justify the use of CL in ethnomedicine, we investigated the vasorelaxant effect of methanolic extract of CL (CLME) and its underlying mechanisms in isolated rat mesenteric artery. MATERIALS AND METHODS: The effect of CLME on the mean arterial pressure (MAP) and heart rate (HR) (pulse interval) were determined in vivo in non-anaesthetized rats. Superior mesenteric rings were isolated, suspended in organ baths containing Tyrode solution at 37 degrees C and gassed with 95% O(2)+5% CO(2), under a resting tension of 0.75 g. The vasorelaxant effects of CLME were studied by means of isometric tension recording experiments. RESULTS: In normotensive rats, CLME (10, 20 and 30 mg/kg, i.v.) induced dose-dependent hypotension (2.0+/-0.5%; 27.1+/-5.0% and 26.7+/-4.6%, respectively), and pronounced bradycardia (5.8+/-1.2%, 19.3+/-3.2% and 22.9+/-4.6%, respectively). CLME (1-1000 microg/mL) induced concentration-dependent relaxation of tonic contractions evoked by phenylephrine (Phe) (10 microM) and KCl (80 mM) in rings with intact-endothelium (E(max)=82.3+/-3.2% and 97.7+/-0.7%) or denuded-endothelium (E(max)=91.4+/-1.0% and 97.8+/-1.1%). Also, in a depolarized, Ca(2+) free medium, CLME inhibited CaCl(2) (1 microM-30 mM)-induced contractions and caused a concentration-dependent rightward shift of the response curves, indicating that CLME inhibited the contractile mechanisms involving extracellular Ca(2+) influx. In addition, in Ca(2+) free media containing EGTA (1 mM), CLME inhibited the transient contraction of denuded rings constricted with Phe, but not those evoked by caffeine (20 mM). In contrast, neither glibenclamide, BaCl(2), tetraethylammonium nor 4-aminopyridine affected CLME-induced relaxation. CONCLUSIONS: These results demonstrate the hypotensive and bradycardic effects of CLME, as well as its potent vasodilation of rat mesenteric arteries. These effects, may in part, be due to the inhibition of extracellular Ca(2+) influx and/or inhibition of intracellular Ca(2+) mobilization from Phe-sensitive stores.

Aspectos biológicos e moleculares de amostras uropatogênicas de Escherichia coli isoladas na Cidade do Rio de Janeiro / Biological and molecular characteristics of uropathogenic Escherichia coli strains isolated in the city of Rio de Janeiro

Amostras uropatogênicas de Escherichia coli isoladas de indivíduos moradores de localidades distintas na Cidade do Rio de Janeiro, foram caracterizadas quanto o sorotipo, propriedades hemolíticas e hemaglutinantes, susceptibilidade a antimicrobianos e perfil isoenzimático. O método molecular empregado associado com a investigação de marcadores de urovirulência, permitiu detectar uma grande diversidade entre os isolados. Entretanto, foi observada uma relação mais estreita entre amostras de Escherichia coli epidemiologicamente relacionadas.

Uropathogenic Escherichia coli strains isolated from individuals living in different areas of the city of Rio de Janeiro were characterized according to serotype, hemolytic properties, hemagglutination properties, antimicrobial susceptibility and isoenzymatic profile. The molecular approach used, together with investigation of urovirulence markers, enabled detection of great diversity among the isolates. However, closer relationships were observed between epidemiologically related Escherichia coli samples.

[Biological and molecular characteristics of uropathogenic Escherichia coli strains isolated in the city of Rio de Janeiro]. / Aspectos biológicos e moleculares de amostras uropatogênicas de Escherichia coli isoladas na Cidade do Rio de Janeiro.

Uropathogenic Escherichia coli strains isolated from individuals living in different areas of the city of Rio de Janeiro were characterized according to serotype, hemolytic properties, hemagglutination properties, antimicrobial susceptibility and isoenzymatic profile. The molecular approach used, together with investigation of urovirulence markers, enabled detection of great diversity among the isolates. However, closer relationships were observed between epidemiologically related Escherichia coli samples.