Changes in carbohydrate expression in the cervical spinal cord of mice intoxicated with perivitellin PV2 from Pomacea canaliculata

FERNÁNDEZ, P.E.; FRASSA,V.; DREON, M.S.; GIMENO, E.; HERAS, H.

Poisoning by plants, mycotoxins and related toxins

CAB international

Lugar: Oxfordshire, UK; Año: 2011; p. 482 - 498

Pomacea canaliculata (Gastropoda: Ampullariidae) is a freshwater South American species, well adapted both to temperate regions, where thermal changes during the year are large  and to subtropical and tropical regions, where periods of drought may alternate with periods of excessive rainfall. They deposit their eggs above the waterline in a calcareous, coloured clutch and have developed a protective and nourishing perivitelline fluid surrounding the embryos. P. canaliculata eggs are provided with a multifunctional perivitellin called ovorubin which plays critical roles for embryo development such as photoprotection, antioxidant, trypsin inhibitor and nutrient provision and also provides the eggs with a pink-reddish colour.  Ovorubin functions are complemented by perivitellin PV2, which has been described as a source of nutrients during embryogenesis  and a potent neurotoxic activity. In a previous work, we identified PV2 perivitellin as the first mollusc neurotoxin genetically encoded outside the cone-snail family Conidae. Upon intraperitoneal injection the toxin provoked death showing signs suggesting neurological damage, we examined the possible effects of the purified toxin on the central nervous system. Clinical signs, histopathological and immunocytochemical studies revealed damage mostly in mice spinal cord. Experiments showed chromatolysis and a decreased response to the Ca-binding protein calbindin D-28K, associated with a significant increase of TUNEL-positive cells of the dorsal horn neurons. This was particularly evident in laminae II and III following the laminar model proposed by Paxinos and Watson, 1986. These results suggest that calcium buffering and apoptosis may play a role in the neurological disorders induced by the toxin in mammalian central nervous system. Further studies about the relationship between immunohistochemical and lectinhistochemical data, on the dorsal grey horn of mice spinal cord, are needed to elucidate the way in which the toxin affects the neuronal synapses and transmission of nociceptive stimulous. In addition, biophysical, molecular biology and pharmacological analyses of the toxin are currently in progress.