Activity of sarafotoxin/endothelin peptides in the heart and brain of lower vertebrates

T. Zigdon-Arad, A. Bdolah, E. Kochva*, Z. Wollberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

The effects of sarafotoxin-b (SRTX-b) and endothelin-1 (ET-1) were tested in the fish tilapia (Ore niloticus × O. aureus hybrids) and torpedo (Torpedo ocellata), the toad (Bufo viridis), the agama lizard (Agama stellio) and water snake (Natrix tessellata). In isolated heart preparations of the fish and agama, peptide doses of 0.05-0.5 μg/ml induced positive inotropic effects, reduction of the contraction rate and arrhythmia, leading to cardiac arrest. In the toad, a negative inotropic effect and a reduction of the contraction rate were observed, whereas the water snake was hardly affected by either SRTX-b or ET-1. In the agama, an i.v. injection of 15 μg of SRTX-b caused changes in the ECG, culminating in A-V block that led to cardiac arrest, while in the toad an injection of 45 μg induced only transient disturbances in the ECG. Binding studies with 125I-SRTX-b revealed specific binding sites for SRTX-b and ET-1 in the heart and brain preparations of fish (tilapia and torpedo) and agama, whereas no specific binding could be demonstrated in the toad or in the snake. These results suggest that most vertebrates tested are sensitive to SRTX/ET, while the snake may possess receptors that are of a different structure.

Original languageEnglish
Pages (from-to)439-448
Number of pages10
JournalToxicon
Volume30
Issue number4
DOIs
StatePublished - Apr 1992

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