Effects of ACL myotoxin, a Lys49 phospholipase A2 from Agkistrodon contortrix laticinctus snake venom, on water transport in the isolated toad urinary bladder

The role of extracellular calcium in the effect of a snake venom Lys49-phospholipase A<sub>2</sub> on water transport across epithelial membranes

“…These findings are particularly relevant to the present study, since toad bladder is a structure whose transport characteristics and response to hormones and drugs resemble those from the mammalian distal nephron [16][17]. Thus, it is possible to suggest that, in addition to the previously well-described effects of Lys49-PLA 2 s myotoxins on renal hemodynamics [3][4][5][6][7][8][9][10][11][12][13][14][15], the direct epithelial actions of these myotoxins may also contribute to their diuretic effect. However, research focusing on the effect of Lys49-PLA 2 s myotoxins on water transport across membranes of mammalian renal epithelial cells would be necessary to confirm this hypothesis.…”

“…The water flow across the bladder epithelium was measured by the gravimetric technique described by Leite et al [8]. All experiments were performed in bladder sacs isolated from Bufo marinus toads, which were kept in an animal room with plenty of food and water, at room temperature, in accordance with the Guide for Care and Use of Laboratory Animals.…”

“…ACLMT is a Lys49-PLA 2 myotoxin isolated from the venom of the snake Agkistrodon contortrix laticinctus [7]. Leite et al [8] demonstrated that ACLMT increases water transport and decreases AVP-stimulated water transport across toad bladder epithelium. The effect of this toxin on water transport is partially mediated by the increased cytosolic calcium, and this increase is a result of the mobilization of calcium from internal stores, as well as of calcium influx across plasma membrane.…”

Differential Myotoxic and Cytotoxic Activities of Pre‐synaptic Neurotoxins from Papuan Taipan (Oxyuranus scutellatus) and Irian Jayan Death Adder (Acanthophis rugosus) Venoms

“…Indeed, many snake venoms and isolated PLA 2 toxins display myotoxicity and cytotoxicity (e.g. Lys-49 phospholipase A 2 of Bothrops asper snake venom) [6][7][8][9][10] which induce membrane disruption and Ca 2+ influx.…”

Ação neurotoxica, miotoxica e citotoxica do veneno de Lachesi muta muta (surucucu)

“…Since our work showed that the LmTX-I induces no cell death or impairment of cell adhesion, it is possible that the decrease in R T induced by this enzyme reflects alterations of the membrane and/or junction permeabilities. Interestingly, previous works have documented that PLA 2 s can affect directly membrane permeability to water and ions (Alix and Woodbury, 1997;Leite et al 2004) and indirectly the tight junction permeability (Sawai et al 2002) in epithelia. Taken altogether, our data show that the LmTX-I is not cytotoxic but displays catalytic activity.…”