Pharmacological kinetics of BmK AS, a sodium channel site 4-specific modulator on Nav1.3

The Significant Therapeutic Effects of Chinese Scorpion: Modern Scientific Exploration of Ion Channels

Chinese scorpion (CS), a traditional animal-based medicine used for over a millennium, has been documented since AD 935-960. It is derived from the scorpion Buthus martensii Karsch and is used to treat various ailments such as stroke, epilepsy, rheumatism, and more. Modern research has identified the pharmacological mechanisms behind its traditional uses, with active components like venom and proteins showing analgesic, antitumor, antiepileptic, and antithrombotic effects. Studies reveal that CS affects ion channels, crucial for cellular functions, through interactions with sodium, potassium, and calcium channels, potentially explaining its therapeutic effects. Future research aims to elucidate the precise mechanisms, target specific ion channel subtypes, and validate clinical efficacy and safety, paving the way for novel therapies based on these natural compounds.

Spider and scorpion knottins targeting voltage-gated sodium ion channels in pain signaling

In sensory neurons that transmit pain signals, whether acute or chronic, voltage-gated sodium channels (VGSCs) are crucial for regulating excitability. NaV1.1, NaV1.3, NaV1.6, NaV1.7, NaV1.8, and NaV1.9 have been demonstrated and defined their functional roles in pain signaling based on their biophysical properties and distinct patterns of expression in each subtype of sensory neurons. Scorpions and spiders are traditional Chinese medicinal materials, belonging to the arachnid class. Most of the studied species of them have evolved venom peptides that exhibit a wide variety of knottins specifically targeting VGSCs with subtype selectivity and conformational specificity. This review provides an overview on the exquisite knottins from scorpion and spider venoms targeting pain-related NaV channels, describing the sequences and the structural features as well as molecular determinants that influence their selectivity on special subtype and at particular conformation, with an aim for the development of novel research tools on NaV channels and analgesics with minimal adverse effects.

Peptides with Diverse Functions from Scorpion Venom: A Great Opportunity for the Treatment of a Wide Variety of Diseases

Toxicology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

The venom glands are a rich source of biologically important peptides with pharmaceutical properties. Scorpion venoms have been identified as a reservoir for components that might be considered as great candidates for drug development. Pharmacological properties of the venom compounds have been confirmed in the treatment of different disorders. Ion channel blockers and AMPs are the main groups of scorpion venom components. Despite the existence of several studies about scorpion peptides, there are still valuable components to be discovered. Additionally, owing to the improvement of proteomics and transcriptomics, the number of peptide drugs is steadily increasing, which reflects the importance of these medications. This review evaluates available literatures on some important scorpion venom peptides with pharmaceutical activities. Given that the last three years have been dominated by the COVID-19 from the medical/pharmaceutical perspective, scorpion compounds with the potential against the coronavirus 2 (SARS-CoV-2) are discussed in this review.

Scorpion Venom: Detriments and Benefits

Scorpion venom may cause severe medical complications and untimely death if injected into the human body. Neurotoxins are the main components of scorpion venom that are known to be responsible for the pathological manifestations of envenoming. Besides neurotoxins, a wide range of other bioactive molecules can be found in scorpion venoms. Advances in separation, characterization, and biotechnological approaches have enabled not only the development of more effective treatments against scorpion envenomings, but have also led to the discovery of several scorpion venom peptides with interesting therapeutic properties. Thus, scorpion venom may not only be a medical threat to human health, but could prove to be a valuable source of bioactive molecules that may serve as leads for the development of new therapies against current and emerging diseases. This review presents both the detrimental and beneficial properties of scorpion venom toxins and discusses the newest advances within the development of novel therapies against scorpion envenoming and the therapeutic perspectives for scorpion toxins in drug discovery.

Peptides with therapeutic potential in the venom of the scorpion Buthus martensii Karsch

The scorpion Buthus martensii Karsch (BmK) has generated significant interest due to the presence of biologically active peptides in its venom. In the past decade, dozens of different peptides from BmK have been identified. Most of the peptides are neurotoxins and are responsible for the toxicity of BmK venom. Other peptides, including neurotoxins and non-disulfide-bridged peptides, show potential anticancer, antimicrobial, analgesic, and anti-epileptic therapeutic effects. These peptides are attractive candidates for drug development, and peptide derivatives have also been designed to enhance their therapeutic potential, such as ADWX-1 and Kn2-7. In this review, we provide an overview of the most promising peptides found in BmK venom and of modified peptide derivatives showing therapeutic potential.

Modulatory effects of bufalin, an active ingredient from toad venom on voltage-gated sodium channels

Chan-su (toad venom) has been used as an analgesic agent in China from ancient to modern times. Bufalin, a non-peptide toxin extracted from toad venom, is considered as one of the analgesic components. The molecular mechanism underlying the anti-nociceptive effects of bufalin remains unclear so far. In this study, we investigated the pharmacological effects of bufalin on pain-related ion channels as well as animal models through patch clamping, calcium imaging and animal behavior observation. Using the whole-cell recording, bufalin caused remarkable suppressive effect on the peak currents of Nav channels (voltage gated sodium channels, VGSCs) of dorsal root ganglion neuroblastomas (ND7-23 cell) in a dose-dependent manner. Bufalin facilitated the voltage-dependent activation and induced a negative shift on the fast inactivation of VGSCs. The recovery kinetics of VGSCs were significantly slowed and the recovery proportion were reduced after administering bufalin. However, bufalin prompted no significant effect not only on Kv4.2, Kv4.3 and BK channels heterologously expressed in HEK293T cells, but also on the capsaicin and allyl isothiocyanate induced Ca²⁺ influx. What's more, bufalin could observably relieve formalin-induced spontaneous flinching and licking response as well as carrageenan-induced thermal and mechanical hyperalgesia in dose-dependent manner in agreement with the results of in vitro experiments. The present results imply that the remarkable anti-nociceptive effects produced by bufalin are probably ascribed to its specific regulation on Nav channels. Bufalin inhibits the Nav channels in a dose-dependent manner, which will provide references for the optimal dose selection of analgesia drugs.

Selective Voltage-Gated Sodium Channel Peptide Toxins from Animal Venom: Pharmacological Probes and Analgesic Drug Development

Voltage-gated sodium channels (Navs) play critical roles in action potential generation and propagation. Nav channelopathy as well as pathological sensitization contribute to allodynia and hyperalgesia. Recent evidence has demonstrated the significant roles of Nav subtypes (Nav1.3, 1.7, 1.8, and 1.9) in nociceptive transduction, and therefore these Navs may represent attractive targets for analgesic drug discovery. Animal toxins are structurally diverse peptides that are highly potent yet selective on ion channel subtypes and therefore represent valuable probes to elucidate the structures, gating properties, and cellular functions of ion channels. In this review, we summarize recent advances on peptide toxins from animal venom that selectively target Nav1.3, 1.7, 1.8, and 1.9, along with their potential in analgesic drug discovery.

Scorpion toxin peptide action at the ion channel subunit level

This review categorizes functionally validated actions of defined scorpion toxin (SCTX) neuropeptides across ion channel subclasses, highlighting key trends in this rapidly evolving field. Scorpion envenomation is a common event in many tropical and subtropical countries, with neuropharmacological actions, particularly autonomic nervous system modulation, causing significant mortality. The primary active agents within scorpion venoms are a diverse group of small neuropeptides that elicit specific potent actions across a wide range of ion channel classes. The identification and functional characterisation of these SCTX peptides has tremendous potential for development of novel pharmaceuticals that advance knowledge of ion channels and establish lead compounds for treatment of excitable tissue disorders. This review delineates the unique specificities of 320 individual SCTX peptides that collectively act on 41 ion channel subclasses. Thus the SCTX research field has significant translational implications for pathophysiology spanning neurotransmission, neurohumoral signalling, sensori-motor systems and excitation-contraction coupling. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'

Voltage-dependent blockade by bupivacaine of cardiac sodium channels expressed in Xenopus oocytes

Bupivacaine ranks as the most potent and efficient drug among class I local anesthetics, but its high potential for toxic reactions severely limits its clinical use. Although bupivacaine-induced toxicity is mainly caused by substantial blockade of voltage-gated sodium channels (VGSCs), how these hydrophobic molecules interact with the receptor sites to which they bind remains unclear. Nav1.5 is the dominant isoform of VGSCs expressed in cardiac myocytes, and its dysfunction may be the cause of bupivacaine-triggered arrhythmia. Here, we investigated the effect of bupivacaine on Nav1.5 within the clinical concentration range. The electrophysiological measurements on Nav1.5 expressed in Xenopus oocytes showed that bupivacaine induced a voltage- and concentration-dependent blockade on the peak of I Na and the half-maximal inhibitory dose was 4.51 μmol/L. Consistent with other local anesthetics, bupivacaine also induced a use-dependent blockade on Nav1.5 currents. The underlying mechanisms of this blockade may contribute to the fact that bupivacaine not only dose-dependently affected the gating kinetics of Nav1.5 but also accelerated the development of its open-state slow inactivation. These results extend our knowledge of the action of bupivacaine on cardiac sodium channels, and therefore contribute to the safer and more efficient clinical use of bupivacaine.

PKA phosphorylation reshapes the pharmacological kinetics of BmK AS, a unique site-4 sodium channel-specific modulator

Although modulation of the activity of voltage-gated sodium channels (VGSCs) by protein kinase A (PKA) phosphorylation has been investigated in multiple preparations, the pharmacological sensitivity of VGSCs to scorpion toxins after PKA phosphorylation has rarely been approached. In this study, the effects of BmK AS, a sodium channel-specific modulator from Chinese scorpion Buthus martensi Karsch, on the voltage-dependent activation and inactivation of Nav1.2 were examined before and after PKA activation. After PKA phosphorylation, the pattern of dose-dependent modulation of BmK AS, on both Nav1.2α and Nav1.2 (α + β1) was reshaped. Meanwhile, the shifts in voltage-dependency of activation and inactivation induced by BmK AS were attenuated. The results suggested that PKA might play a role in different patterns how β-like toxins such as BmK AS modulate gating properties and peak currents of VGSCs.