First report on an inotropic peptide activating tetrodotoxin-sensitive, "neuronal" sodium currents in the heart.

Background: New therapeutic approaches to improve cardiac contractility without severe risk would improve the management of acute heart failure. Increasing systolic sodium influx can increase cardiac contractility, but most sodium channel activators have proarrhythmic effects that limit their clinical use. Here, we report the cardiac effects of a novel positive inotropic peptide isolated from the toxin of the Black Judean scorpion that activates neuronal tetrodotoxin-sensitive sodium channels.

The sea anemone toxin AdE-1 modifies both sodium and potassium currents of rat cardiomyocytes.

AdE-1, a cardiotonic peptide recently isolated from the sea anemone Aiptasia diaphana, contains 44 amino acids and has a molecular mass of 4907 Da. It was previously found to resemble other sea anemone type 1 and 2 Na+ channel toxins, enhancing contractions of rat cardiomyocytes and slowing their twitch relaxation; however, it did not induce spontaneous twitches. AdE-1 increased the duration of the cardiomyocyte action potential and decreased its amplitude and its time-to-peak in a concentration-dependent manner, without affecting its threshold and cell resting potential.

AdE-1, a new inotropic Na(+) channel toxin from Aiptasia diaphana, is similar to, yet distinct from, known anemone Na(+) channel toxins.

Heart failure is one of the most prevalent causes of death in the western world. Sea anemone contains a myriad of short peptide neurotoxins affecting many pharmacological targets, several of which possess cardiotonic activity. In the present study we describe the isolation and characterization of AdE-1 (ion channel modifier), a novel cardiotonic peptide from the sea anemone Aiptasia diaphana, which differs from other cnidarian toxins.

Gene construction, expression and functional testing of an inotropic peptide from the venom of the black scorpion Hottentotta judaicus.

Anti-insect depressant toxins represent a subfamily of scorpion venom-derived β-toxins that are polypeptides composed of 61-65 amino acid residues stabilized by four disulfide bridges. These toxins affect the activation of voltage-sensitive sodium channels (NaScTx) and exhibit the preferential ability to induce flaccid paralysis in insect larvae. Here we demonstrate the recombinant expression of the novel cardiac inotropic peptide (Bj-IP) that was classified as an anti-insect depressant βNaScTx isolated from the venom of Hottentotta judaicus.

The tale of a resting gland: transcriptome of a replete venom gland from the scorpion Hottentotta judaicus.

cDNA libraries are increasingly being used for high-throughput interrogation of animal venomes. Most previous studies have focused on discovery of new venom toxins, whereas the dynamics of toxin transcription and associated cellular processes have received much less attention. Here we provide, for the first time, an analysis of a transcriptome from the venom gland of a scorpion (Hottentotta judaicus) that is not actively engaged in regenerating its venom.