Abstract
Leiurus quinquestriatus is one of the dangerous scorpions all over the world and represents a health hazards in Egypt. It has garnered a lot of attention after the isolation of a peptide called chlorotoxin from its venom which used for identification and treatment of gliomas. The present study was carried out to critically describe the morphology, histology, histochemistry and ultrastructure of its venom gland before and after milking to understand the mode of venom formation and secretion in this medically important scorpion. Microscopical examination revealed that the venom apparatus of L. quinquestriatus is composed of paired venom glands situated inside the telson's vesicle. Two venom ducts extend from these glands to open at the subterminal sides of the stinger. SEM revealed the presence of many sensory setae over the cuticle of venom apparatus. The venom epithelium is highly folded and has three types of cells: venom-producing cells, mucous (goblet) cells and supporting cells. Three types of distinct secretory granules were found in venom-producing cells that gave a variable positive response with histological and histochemical stains reflecting their constituent's richness. The herein results revealed also that these granules are distinct types and no transitional stages reflecting that they are at a maturation stage.The mode of venom secretion from venom glands of the studied species were found to be of apocrine type. Ultrastructural architecture of these cells and their granules were described.