Snake Venom and Antivenom Pharmacology

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  SNAKE VENOM & ANTIVENOM Chemistry, Composition, Mechanisms and Pharmacology Abstract This integrated teaching session for Phase III MBBS students focused on the pharmacology and toxicology of snake venom and the principles of antivenom therapy. The lecture covered the chemistry, composition, mechanisms of action, and pharmacological effects of snake venoms and antivenoms. Rational use of antivenoms, indications, administration protocols, adverse reactions, and supportive management strategies were discussed. The session also highlighted the translational importance of venom-derived compounds in modern drug development. Recent advances in antivenom research, including recombinant human monoclonal antibodies, toxin-specific inhibitors, synthetic antibody technologies, and next-generation broad-spectrum antivenoms, were reviewed. Current discoveries and emerging approaches aimed at improving efficacy, safety, affordability, and accessibility of antivenom therapy were also explor...

Semi-hydraulic actuation in spider legs: The transport of the hemolymph does not hamper muscle driven leg joint flexion

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Semi-hydraulic actuation in spider legs: The transport of the hemolymph does not hamper muscle driven leg joint flexion

Abstract

Hemolymph channels (lacunae) in the legs of spiders are part of their open circulatory system. They are defined as hemolymph-filled spaces between tissues within the exoskeletal tubes of the legs which are otherwise largely filled with muscles. In two of the major leg joints, the leg segments are connected via hinge joints with axes that are located at their dorsal rims.
The lacunae are used to channel hemolymph, which acts as a hydraulic fluid, to the extensor-less joints during the extension of the legs. However, due to competing optimization criteria of muscle-driven flexion and drainage of the hemolymph, fluid drag in the lacunae may hinder movement and force generation during flexion. Numerical modelling of dynamic flexions of the tibia-metatarsus joint, considering anatomical and physiological properties identified in the hunting spider Cupiennius salei, was used to investigate the trade-off between muscular force and hemolymph-drainage. The results showed that the diameters of the hemolymph channels exhibit a broad optimum for quick flexion. Within a wide range of channel diameters flexion times are hardly affected. Muscle properties, especially the time of muscle activation, strongly dampen the effect of the reduced muscle cross-section available. With small loads of 0.1g, similar to the spiders’ common prey size, the radius of the observed effective lacunae seems to enable the fastest flexions. A change in the aspect ratio of the tibia while maintaining the proportionality of its radius and the radius of the effective hemolymph channels leads to an extension of the flexion time.
Blickhan, R., Siebert, T., & Weihmann, T. (2026). Semi-hydraulic actuation in spider legs: The transport of the hemolymph does not hamper muscle driven leg joint flexion. Journal of Theoretical Biology, 620, 112350. https://doi.org/10.1016/j.jtbi.2025.112350