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Cardiovascular effects of Sp-CTx, a cytolysin from the scorpionfish (Scorpaena plumieri) venom
- Source :
- Toxicon. 118:141-148
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- 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 β-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.
- Subjects :
- Fish Proteins
Male
0301 basic medicine
medicine.medical_specialty
Patch-Clamp Techniques
Blood Pressure
Venom
Propranolol
In Vitro Techniques
Biology
Toxicology
Cardiotoxins
03 medical and health sciences
chemistry.chemical_compound
Fish Venoms
Heart Rate
In vivo
Coronary Circulation
Internal medicine
medicine
Scorpaena
Animals
Vasoconstrictor Agents
Myocytes, Cardiac
Rats, Wistar
Cells, Cultured
Glycoproteins
030102 biochemistry & molecular biology
Perforin
Heart
Papillary Muscles
Tyramine
biology.organism_classification
Perciformes
Endocrinology
chemistry
Injections, Intravenous
Catecholamine
Cytolysin
medicine.symptom
Brazil
Vasoconstriction
Muscle Contraction
medicine.drug
Subjects
Details
- ISSN :
- 00410101
- Volume :
- 118
- Database :
- OpenAIRE
- Journal :
- Toxicon
- Accession number :
- edsair.doi.dedup.....4a5028523cf971921ca7cd1bb746ba0e