Barietin, a snake venom vascular endothelial growth factor from puff adder Bitis arietans venom, increases the heart rate with minor effect on blood pressure in rats

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  Barietin, a snake venom vascular endothelial growth factor from puff adder Bitis arietans venom, increases the heart rate with minor effect on blood pressure in rats ABSTRACT Snake venom vascular endothelial growth factors (svVEGFs) are homodimeric proteins comprising two equal subunits bound by two intermolecular disulfide bonds. The main biological effects of svVEGFs are local vasodilatation, increasing of vascular permeability, and hypotension. Barietin, a svVEGF purified from the venom of puff adder Bitis arietans , differs from other representatives of this toxin family by its shortened C-terminal amino acid sequence. No data about barietin effects on hemodynamics are available. Studying those in rats we found that barietin at a dose of 1 mg/kg significantly increased heart rate, exerting only a minor influence on blood pressure. In this respect, it differs from other svVEGFs having a significant effect on blood pressure. We aimed to find the barietin active fragment which m...

Under pressure: mapping the distribution of medically important Tityus Koch, 1836 (Buthidae) scorpions in Brazil using a century of Instituto Butantan records

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Under pressure: mapping the distribution of medically important Tityus Koch, 1836 (Buthidae) scorpions in Brazil using a century of Instituto Butantan records

Abstract

The buthid scorpions Tityus serrulatus, T. bahiensis, T. obscurus, and T. stigmurus are considered the most medically significant species in Brazil. Since the early 1900s, their identification and distribution have been central to the zoological collections of the Instituto Butantan (IBSP). In this study, we map the distribution of these species using 7241 presence-only records from the IBSP collected since 1905. Species richness and record density were analyzed using 2° grid cells, and spatial overlap was assessed via a Jaccard similarity index. Based on our dataset of species records, Tityus serrulatus showed the broadest distribution, present in nearly all Brazilian states except Rio Grande do Norte, Maranhão, Amapá, and Roraima, with the highest densities in São Paulo and northern Paraná. Tityus bahiensis had the second widest range, with dense occurrences largely restricted to São Paulo. Mesoregions in São Paulo (Macrometropolitana Paulista, Metropolitana de São Paulo) and Paraná (Noroeste, Norte-Central) have the highest probability of encountering medically significant Tityus species, considering the density of records obtained from the IBSP collection. Also, we emphasize the importance of implementing long-term monitoring programs and conducting new species surveys, especially in high-risk areas and current species distribution gaps.
Goldoni, P. A., Brescovit, A. D., Castro-Souza, R. A., Cequinel, J., Marques-da-Silva, E., & Iniesta, L. F. (2025). Under pressure: Mapping the distribution of medically important Tityus Koch, 1836 (Buthidae) scorpions in Brazil using a century of Instituto Butantan records. Toxicon, 268, 108627. https://doi.org/10.1016/j.toxicon.2025.108627