Changes in the arterial blood pressure, heart rate and normal ECG parameters of rat after envenomation with Egyptian cobra (Naja haje) venom

Isolation and characterization of renin-like aspartic-proteases from Echis ocellatus venom

Three aspartic proteases (SVAPs) have been isolated from venom of the saw-scaled viper, Echis ocellatus. In confirmation of prior transcriptomic predictions, all three forms match to sequences of either of the two SVAP transcripts (EOC00051 and EOC00123), have a molecular weight of 42 kDa and possess a single N-glycan. The SVAPs act in a renin-like manner, specifically cleaving human and porcine angiotensinogen into angiotensin-1 and possess no general protease activity. Their activity is completely inhibited by the aspartyl protease inhibitor Pepstatin A.

Synthetic peptide antigens derived from long-chain alpha-neurotoxins: Immunogenicity effect against elapid venoms

Three-finger toxins (3FTXs), especially α-neurotoxins, are the most poorly neutralized elapid snake toxins by current antivenoms. In this work, the conserved structural similarity and motif arrangements of long-chain α-neurotoxins led us to design peptides with consensus sequences. Eight long-chain α-neurotoxins (also known as Type II) were used to generate a consensus sequence from which two peptides were chemically synthesized, LCP1 and LCP2. Rabbit sera raised against them were able to generate partially-neutralizing antibodies, which delayed mice mortality in neutralization assays against Naja haje, Dendrospis polylepis and Ophiophagus hannah venoms.

Proteomic analysis of Moroccan cobra Naja haje legionis venom using tandem mass spectrometry

The proteome of the venom of Naja haje legionis, the only medically important elapid species in Morocco, has been elucidated by using a combination of proteomic techniques that includes size exclusion chromatography, reverse-phase HPLC, Tricine/SDS-Page, tryptic digestion, Q-TOF tandem mass spectrometry and database search. The sequence analysis of venom fractions revealed a highly complex venom proteome which counts a total of 76 proteins identified from database that can be assigned into 9 proteins families. We report the identification of: cobra venom factor (CVF), l-amino-acid oxidases (LAAO), acetylcholinesterase (AChE), snake venom metalloproteinases (SVMP), cysteine rich secretory proteins (CRISP), venom nerve growth factor (vNGF), phospholipases A2 (PLA2), vespryns, kunitz-type inhibitor, short neurotoxins, long neurotoxins, weak neurotoxins, neurotoxin like proteins, muscarinic toxins, cardiotoxins and cytotoxins. Comparison of these proteins showed high sequence homology with proteins from other African and Asian cobras. Further works are needed to assess the contribution of individual toxins in venom toxicity.

BIOLOGICAL SIGNIFICANCE

Naja haje legionis is one of the medically important snakes implicated in the pathogenesis of snake bite in Morocco. The absence of information about venom composition and clinical manifestations of envenomation by this cobra represents an obstacle for the management of this environmental disease in the country. The elucidation of Moroccan cobra venom composition will provide a reasonable guidance for clinician to understand the pathophysiological conditions associated with cobra envenomation and the elaboration of better management strategies.

Measurement of invasive blood pressure in rats

Blood pressure (BP) is one of the vital parameters used to assess the cardiovascular functions of a mammal. BP is commonly recorded using invasive, noninvasive, and radio telemetry methods, but invasive blood pressure (IBP) recording is considered the gold standard. IBP provides a direct indication of the effect of the investigational products on the circulatory system. Recording the IBP in rodents is an essential part of the preliminary screening of any product to determine its effect on the cardiovascular system. The present article describes the measurement of the IBP in Wistar rats/Sprague Dawley rats.

Weak neurotoxin from Naja kaouthia cobra venom affects haemodynamic regulation by acting on acetylcholine receptors

Recent in vitro studies of weak neurotoxins from snake venoms have demonstrated their ability to interact with both muscle-type and neuronal alpha7 nicotinic acetylcholine receptors (nAChR). However, the biological activity in vivo of weak neurotoxins remains largely unknown. We have studied the influence of weak neurotoxin (WTX) from the venom of cobra Naja kaouthia on arterial blood pressure (BP) and heart rate (HR) in rats and mice. It was found that intravenous injection of WTX induced a dose-dependent decrease in BP and an increase in HR in both species, the rats being more sensitive to WTX. Application of WTX following blockade of nAChRs or muscarinic acetylcholine receptors (mAChR) by hexamethonium or atropine, respectively, showed that both nAChRs and mAChRs are involved in the haemodynamic effects of WTX. Blockade of either nAChRs or mAChRs affected WTX action differently in rats and mice, thus reflecting interspecies differences in haemodynamic regulation.