Biochemistry Studies Of The Stingrays (Potamotrygon motoro) Venom.

¹Magalhães, M. R., ²Ulhoa, C. J. and ¹Silva Jr., N. J.

1 Centro de Estudos e Pesquisas Biológicas, Univesidade Católica de Goiás; 2 Instituto de Ciências Biológicas, Universidade Federal de Goiás.

Stingrays have been regarded as the most important group of venomous fishes. In Brazil the accidents are frequent in Midwest and North regions, especially during the dry season, when humans seek the sandbanks of the rivers, for recreation, especially in the State of Goiás. The wound is inflicted by a sting on the dorsal posterior surface of a whiplike appendage on the caudal end of the animal. Pain is the first and often predominant symptom of the envenomation. The lesion presents local edema and progressive local necrosis, ulceration and even gangrene. The objective of this study is to contribute to the biochemical knowledge of the venom of freshwater stingrays since very little is known about its enzymatic characteristics and the envenomation. The venom of Potamotrygonmotoro extracted from the sting was tested  for  the following enzymatic activities: phosphodiesterase, acid and alkaline phosphomonoesterases, 5´-nucleotidase, phospholipase, hyaluronidase, proteolytic activity on casein, gelatin and elastin. The results were positive in 7 of the 9 assays performed, with hyaluronidase, 5´-nucleotidase, and proteolytic activity on elastin being the most significant. The activities of phosphodiesterase and alkaline phosphomonoesterase were not detected. The data presented suggest the participation of these enzymes in the envenomation by freswater stingrays of the specie Potamotrygonmotoro in a fashion not yet fully understood.

Correspondence to:  artarm@terra.com.br