RESUMEN
Cardiovascular effects induced by snake venoms, in spite of having a crucial role in the outcome of the envenomation, have been less studied than other toxic activities displayed by these venoms. In this study we evaluated acute cardiovascular responses to Bothrops leucurus venom - Bl-V - both in vivo, in anesthetized rats, and in vitro, in isolated rat mesenteric resistance arteries. Bl-V (10-100 µg protein/kg) caused dose-dependent hypotension, followed by gradual recovery (2-20 min) to basal levels, and induced dose-dependent (1-20 µg/mL) vasodilation in pre-contracted arteries, what was more pronounced when the endothelium remained intact. These effects were partially counteracted by pre-treatment with indomethacin (cyclooxygenase inhibitor). Prior incubation of Bl-V with commercial pentavalent Bothrops antivenom also attenuated the cardiovascular effects induced by the venom, in spite of it not being among the venoms used for the development of the bothropic antivenom. Through an approach based on two chromatographic steps and mass spectrometry (MALDI-ToF and MALDI-ISD), a component with acute cardiovascular effects was isolated and identified as the basic phospholipase blD-PLA2, previously purified from the venom of B. leucurus. Taken together, our results show that, at low doses, the venom of B. leucurus induces transient, acute hypotension in anesthetized rats following systemic vasodilation in a dose-dependent way. In addition, we provide clear evidence of the involvement of the enzymatic activity of blD-PLA2 in this cardiovascular response, acting via the production of vasodilating prostanoids.
Asunto(s)
Bothrops , Venenos de Crotálidos/toxicidad , Fosfolipasas A2/metabolismo , Animales , Hipotensión/inducido químicamente , Ratas , Venenos de SerpienteRESUMEN
The most poisonous fish species found along the Brazilian coast is the spotted scorpionfish Scorpaena plumieri. Though hardly ever life-threatening to humans, envenomation by S. plumieri can be quite hazardous, provoking extreme pain and imposing significant socioeconomic costs, as the victims may require days to weeks to recover from their injuries. In this review we will walk the reader through the biological features that distinguish this species as well as the current epidemiological knowledge related to the envenomation and its consequences. But above all, we will discuss the challenges involved in the biochemical characterization of the S. plumieri venom and its compounds, focusing then on the successful isolation and pharmacological analysis of some of the bioactive molecules responsible for the effects observed upon envenomation as well as on experimental models. Despite the achievement of considerable progress, much remains to be done, particularly in relation to the non-proteinaceous components of the venom. Therefore, further studies are necessary in order to provide a more complete picture of the venom's chemical composition and physiological effects. Given that fish venoms remain considerably less studied when compared to terrestrial venoms, the exploration of their full potential opens a myriad of possibilities for the development of new drug leads and tools for elucidating the complex physiological processes.
RESUMEN
Fish venom cytolysins are multifunctional proteins that in addition to their cytolytic/hemolytic effects display neurotoxic, cardiotoxic and inflammatory activities, being described as "protein lethal factors". A pore-forming cytolysin called Sp-CTx (Scorpaena plumieriCytolytic Toxin) has been recently purified from the venom of the scorpionfish Scorpaena plumieri. It is a glycoprotein with dimeric constitution, comprising subunits of approximately 65 kDa. Previous studies have revealed that this toxin has a vasorelaxant activity that appears to involve the L-arginine-nitric oxide synthase pathway; however its cardiovascular effects have not been fully comprehended. The present study examined the cardiovascular effects of Sp-CTx in vivo and in vitro. In anesthetized rats Sp-CTx (70 µg/kg i.v) produced a biphasic response which consisted of an initial systolic and diastolic pressure increase followed by a sustained decrease of these parameters and the heart rate. In isolated rats hearts Sp-CTx (10(-9) to 5 × 10(-6) M) produced concentration-dependent and transient ventricular positive inotropic effect and vasoconstriction response on coronary bed. In papillary muscle, Sp-CTx (10(-7) M) also produced an increase in contractile isometric force, which was attenuated by the catecholamine releasing agent tyramine (100 µM) and the ß-adrenergic antagonist propranolol (10 µM). On isolated ventricular cardiomyocytes Sp-CTx (1 nM) increased the L-type Ca(2+) current density. The results show that Sp-CTx induces disorders in the cardiovascular system through increase of sarcolemmal calcium influx, which in turn is partially caused by the release of endogenous noradrenaline.
Asunto(s)
Cardiotoxinas/toxicidad , Circulación Coronaria/efectos de los fármacos , Venenos de los Peces/química , Corazón/efectos de los fármacos , Músculos Papilares/efectos de los fármacos , Perciformes , Perforina/toxicidad , Animales , Presión Sanguínea/efectos de los fármacos , Brasil , Cardiotoxinas/administración & dosificación , Cardiotoxinas/aislamiento & purificación , Células Cultivadas , Proteínas de Peces/administración & dosificación , Proteínas de Peces/aislamiento & purificación , Proteínas de Peces/toxicidad , Glicoproteínas/administración & dosificación , Glicoproteínas/aislamiento & purificación , Glicoproteínas/toxicidad , Corazón/fisiología , Frecuencia Cardíaca/efectos de los fármacos , Técnicas In Vitro , Inyecciones Intravenosas , Masculino , Contracción Muscular/efectos de los fármacos , Miocitos Cardíacos/citología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Músculos Papilares/fisiología , Técnicas de Placa-Clamp , Perforina/administración & dosificación , Perforina/aislamiento & purificación , Ratas Wistar , Vasoconstrictores/administración & dosificación , Vasoconstrictores/aislamiento & purificación , Vasoconstrictores/toxicidadRESUMEN
The most poisonous fish species found along the Brazilian coast is the spotted scorpionfish Scorpaena plumieri. Though hardly ever life-threatening to humans, envenomation by S. plumieri can be quite hazardous, provoking extreme pain and imposing significant socioeconomic costs, as the victims may require days to weeks to recover from their injuries. In this review we will walk the reader through the biological features that distinguish this species as well as the current epidemiological knowledge related to the envenomation and its consequences. But above all, we will discuss the challenges involved in the biochemical characterization of the S. plumieri venom and its compounds, focusing then on the successful isolation and pharmacological analysis of some of the bioactive molecules responsible for the effects observed upon envenomation as well as on experimental models. Despite the achievement of considerable progress, much remains to be done, particularly in relation to the non-proteinaceous components of the venom. Therefore, further studies are necessary in order to provide a more complete picture of the venoms chemical composition and physiological effects. Given that fish venoms remain considerably less studied when compared to terrestrial venoms, the exploration of their full potential opens a myriad of possibilities for the development of new drug leads and tools for elucidating the complex physiological processes.(AU)
Asunto(s)
Animales , Venenos de los Peces/análisis , Venenos de los Peces/química , Venenos de los Peces/farmacología , Venenos de los Peces/toxicidad , Sinergismo FarmacológicoRESUMEN
The most poisonous fish species found along the Brazilian coast is the spotted scorpionfish Scorpaena plumieri. Though hardly ever life-threatening to humans, envenomation by S. plumieri can be quite hazardous, provoking extreme pain and imposing significant socioeconomic costs, as the victims may require days to weeks to recover from their injuries. In this review we will walk the reader through the biological features that distinguish this species as well as the current epidemiological knowledge related to the envenomation and its consequences. But above all, we will discuss the challenges involved in the biochemical characterization of the S. plumieri venom and its compounds, focusing then on the successful isolation and pharmacological analysis of some of the bioactive molecules responsible for the effects observed upon envenomation as well as on experimental models. Despite the achievement of considerable progress, much remains to be done, particularly in relation to the non-proteinaceous components of the venom. Therefore, further studies are necessary in order to provide a more complete picture of the venom's chemical composition and physiological effects. Given that fish venoms remain considerably less studied when compared to terrestrial venoms, the exploration of their full potential opens a myriad of possibilities for the development of new drug leads and tools for elucidating the complex physiological processes.(AU)
Asunto(s)
Animales , Péptido Hidrolasas , Venenos de los Peces/toxicidad , Peces , InflamaciónRESUMEN
The most poisonous fish species found along the Brazilian coast is the spotted scorpionfish Scorpaena plumieri. Though hardly ever life-threatening to humans, envenomation by S. plumieri can be quite hazardous, provoking extreme pain and imposing significant socioeconomic costs, as the victims may require days to weeks to recover from their injuries. In this review we will walk the reader through the biological features that distinguish this species as well as the current epidemiological knowledge related to the envenomation and its consequences. But above all, we will discuss the challenges involved in the biochemical characterization of the S. plumieri venom and its compounds, focusing then on the successful isolation and pharmacological analysis of some of the bioactive molecules responsible for the effects observed upon envenomation as well as on experimental models. Despite the achievement of considerable progress, much remains to be done, particularly in relation to the non-proteinaceous components of the venom. Therefore, further studies are necessary in order to provide a more complete picture of the venoms chemical composition and physiological effects. Given that fish venoms remain considerably less studied when compared to terrestrial venoms, the exploration of their full potential opens a myriad of possibilities for the development of new drug leads and tools for elucidating the complex physiological processes.
Asunto(s)
Animales , Venenos de los Peces/análisis , Venenos de los Peces/farmacología , Venenos de los Peces/química , Venenos de los Peces/toxicidad , Sinergismo FarmacológicoRESUMEN
Previously, a potent hemolytic toxin (Sp-CTx - 121 kDa) was isolated from Atlantic Scorpionfish Scorpaena plumieri venom. In the present work, we aimed to elucidate the action mechanisms involved in the hemolytic activity induced by this toxin, but to achieve our goal we faced the need to optimize its purification procedure in order to improve its activity and protein recovery. In this new method, Sp-CTx was purified to homogeneity through a combination of sequential ammonium sulfate precipitation and two chromatographic steps: hydrophobic interaction (Butyl HP) and anion exchange (Synchropak SAX 300). Orbitrap mass spectrometry analysis revealed that the amino acids sequences determined to Sp-CTx peptides are shared by other hemolytic toxins from fish venoms. The hemolytic activity of Sp-CTx upon rabbit erythrocytes was attenuated in the presence of osmotic protectants (polyethylene glycol polymers), and molecules larger than 6 nm in diameter inhibited cell lysis. This result strongly suggests that Sp-CTx may be a pore-forming protein, since it lacks phospholipase A2 activity. All these results contribute to the better understanding of Sp-CTx molecular/cellular actions in envenomation caused by S. plumieri. The results are also in agreement with previous reports of structural and functional similarities among piscine hemolytic toxins.
Asunto(s)
Membrana Eritrocítica/efectos de los fármacos , Eritrocitos/efectos de los fármacos , Venenos de los Peces/química , Perciformes , Perforina/química , Animales , Fenómenos Químicos , Electroforesis en Gel de Poliacrilamida , Eritrocitos/citología , Hemólisis/efectos de los fármacos , Perforina/aislamiento & purificación , Fosfolipasas A2/metabolismo , ConejosRESUMEN
The Scorpaena plumieri fish venom induces a severe pain and edema, observed both clinically and experimentally. In order to understand more about the envenomation syndrome, the present study characterized experimentally the local acute inflammatory response induced by S. plumieri venom (SpV) in a mouse model of tissue injury. Our results demonstrated that the local inflammatory response provoked after 2 h of SpV injection in footpad of mice is characterized by release of pivotal pro-inflammatory mediators (TNF, IL-6 and MCP-1). These mediators could be associated with histopathological changes observed into paw tissue, characterized by cellular infiltration, mainly neutrophils. Additionally, an investigation of edema formation pathways involved in inflammatory response was performed. SpV-induced edema was reduced significantly by previous administration of aprotinin or icatibant (HOE-140). However, the pre-treatment with diclofenac sodium and promethazine had less effect on this response. These results demonstrate that the kallikrein-kinin system (KKS) plays a major role in the edema formation. Despite the whole venom hydrolyzed the kallikrein synthetic substrate S-2302 (Pro-Phe-Arg-pNA), its main pro-inflammatory fraction was devoid of kininogenase activity. Our results demonstrate that SpV evokes a complex inflammatory reaction stimulating a secretion of TNF, IL-6, MCP-1 and leukocytes recruitment at the site of venom injection. In addition provide clear evidence of the involvement of the KKS in inflammatory response induced by S. plumieri venom.
Asunto(s)
Peces , Inflamación/inducido químicamente , Toxinas Marinas/toxicidad , Animales , Antiinflamatorios/uso terapéutico , Quimiocinas/metabolismo , Citocinas/metabolismo , Inflamación/tratamiento farmacológico , Masculino , RatonesRESUMEN
Several studies have demonstrated that gonadal hormones show significant effects on the brain and signaling pathways of effector organs/cells that respond to neurotransmitters. Since little information is available concerning the impact of male and female gonadal hormones on the renal and peripheral sympathetic system, the objective of this study was to further assess whether and how the renal content and plasma concentration of catecholamines are influenced by gender and the estrous cycle in rats. To achieve this, males Wistar rats were divided into 4 groups: (i) sham (i.e., control), (ii) gonadectomized, (iii) gonadectomized and nandrolone decanoate replacement at physiological levels or (iv) gonadectomized and nandrolone decanoate replacement at high levels. Female Wistar rats were divided into 6 groups: (i) ovariectomized (OVX), (ii) estrogen replacement at physiological levels and (iii) estrogen replacement at at high levels, (iv) progesterone replacement at physiological levels and (v) progesterone replacement at at high levels, and (vi) sham. The sham group was subdivided into four subgroups: (i) proestrus, (ii) estrus, (iii) metaestrus, and (iv) diestrus. Ten days after surgery, the animals were sacrificed and their plasma and renal catecholamine levels measured for intergroup comparisons. Gonadectomy led to an increase in the plasma catecholamine concentration in females, as well as in the renal catecholamine content of both male and female rats. Gonadectomized males also showed a lower level of plasma catecholamine than the controls. The urinary flow, and the fractional excretion of sodium and chloride were significantly increased in gonadectomized males and in the OVX group when compared with their respective sham groups.
Asunto(s)
Catecolaminas/sangre , Catecolaminas/metabolismo , Ciclo Estral/sangre , Ciclo Estral/metabolismo , Riñón/metabolismo , Animales , Cloruros/orina , Relación Dosis-Respuesta a Droga , Estradiol/administración & dosificación , Estradiol/farmacología , Femenino , Hormonas Gonadales/administración & dosificación , Hormonas Gonadales/farmacología , Riñón/efectos de los fármacos , Riñón/fisiopatología , Masculino , Nandrolona/administración & dosificación , Nandrolona/análogos & derivados , Nandrolona/farmacología , Nandrolona Decanoato , Orquiectomía/métodos , Orquiectomía/estadística & datos numéricos , Ovariectomía/métodos , Ovariectomía/estadística & datos numéricos , Progesterona/administración & dosificación , Progesterona/farmacología , Ratas , Ratas Wistar , Caracteres Sexuales , Sodio/orina , Micción/efectos de los fármacos , Micción/fisiologíaRESUMEN
Venomous fish are often involved in human accidents and symptoms of envenomation include local (intense pain and swelling) and systemic effects (cardiovascular and neurological disorders). However the only commercially available antivenom is against the Indo-Pacific stonefish Synanceja trachynisStonefish Antivenom (SFAV). The aim of the present study was to evaluate the potential of SFAV in neutralising the in vivo effects of some toxic activities of scorpionfish Scorpaena plumieri venom (SpV), and the in vitro immuno cross-reactivity. The SpV (7.5-100 µg/animal) caused nociceptive and dose-dependent edematogenic responses in the mice footpad. In rats SpV (300 µg/kg, i.v.) produced immediate and transient increase in arterial blood pressure and decrease in heart rate. Prior incubation of SpV with SFAV (1 µg SpV/1 U SFAV) abolished the inflammatory response, and significantly attenuated the cardiovascular effects induced by SPV. Western blotting analysis on two-dimensional SDS-PAGE of S plumieri venom proteins using SFAV proved that the epitopes recognized by SFAV are shared with the â¼98 kDa proteins. This is the first report of venom similarities between Indo-Pacific and Atlantic venomous fish, suggesting that the SpV compound responsible for inflammatory and cardiovascular effects possesses similar biochemical and antigenic properties to those found in stonefish venom.
Asunto(s)
Antivenenos/uso terapéutico , Enfermedades Cardiovasculares/tratamiento farmacológico , Venenos de los Peces/antagonistas & inhibidores , Peces Venenosos , Inflamación/tratamiento farmacológico , Animales , Antivenenos/química , Presión Sanguínea/efectos de los fármacos , Enfermedades Cardiovasculares/inducido químicamente , Relación Dosis-Respuesta a Droga , Frecuencia Cardíaca/efectos de los fármacos , Inflamación/inducido químicamente , Masculino , Ratones , Ratas , Ratas WistarRESUMEN
The aim of the present study was to investigate the cardiovascular activity of Scorpaena plumieri venom in both in vivo and in vitro models. In anesthetized rats, doses of the venom (14-216 microg protein/kg) induced a transient increase in the mean arterial pressure. However at higher dose (338 microg protein/kg) this effect was followed by a sudden hypotension and the animal evolved to death. The heart rate was temporarily increased and followed by bradycardia using doses > or =108 microg/kg. In isolated rat hearts the crude venom (5-80 microg protein) produced dose-dependent positive ventricular chronotropic, inotropic, lusitropic and coronary vasoconstriction responses. Partial purification of an active fraction (CF, cardiovascular fraction) which reproduced the cardiovascular effects induced by crude venom on isolated hearts was achieved by conventional gel filtration chromatography. Adrenergic blockades, prazosin and propranolol, significantly attenuated these responses. The coronary vasoconstriction response to CF was also attenuated by chemical endothelium denudation. In conclusion, the data showed that S. plumieri fish venom induces disorders in the cardiovascular system. It also suggests that alpha(1) and beta-adrenergic receptors, and the vascular endothelium, are involved at least partially, in these cardiac effects.