Histochemistry and Cell Biology

, Volume 132, Issue 4, pp 395–404

The neurotoxicological effects of mastoparan Polybia-MPII at the murine neuromuscular junction: an ultrastructural and immunocytochemical study

  • Thalita Rocha
  • Bibiana M. de Souza
  • Mario S. Palma
  • Maria Alice da Cruz-Höfling
  • John Buchanan Harris
Original Paper

DOI: 10.1007/s00418-009-0607-z

Cite this article as:
Rocha, T., de Souza, B.M., Palma, M.S. et al. Histochem Cell Biol (2009) 132: 395. doi:10.1007/s00418-009-0607-z

Abstract

Polybia-MPII (INWLKLGKMVIDAL-NH2), a mastoparan isolated from the crude venom of the swarming wasp Polybia paulista, was injected into the left hind limb of Swiss white mice. Between 3 h and 21 days later the mice were killed and the soleus muscles from both hind limbs were removed. Sections of the muscles were made for transmission electron microscopy and immunocytochemistry. Transmission electron microscopy showed that both the volume fraction occupied by synaptic vesicles and synaptic vesicle density was greatly reduced after exposure to Polybia-MPII, although there was no significant structural damage to the plasma membrane of the terminal boutons and mitochondria were indistinguishable from those in normal, control boutons. Immunocytochemistry revealed that in control muscles 99% of motor end plates identified by the positive labelling of acetylcholine receptors by TRITC-α-bungarotoxin co-labelled with anti-synaptophysin antibody, but this figure fell by 30% in muscles exposed to the toxin. These changes were transient. They were maximal at 6 h and fully reversed by 3 days. At no time was axonal labelling with anti-neurofilament antibodies affected by exposure to Polybia-MPII. We conclude that mastoparan Polybia-MPII is a minor neurotoxin and suggest that its neurotoxic activity is unlikely to be of clinical significance.

Keywords

WaspPolybia paulistaSynaptic vesiclesSynaptophysinNeurofilaments

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Thalita Rocha
    • 1
  • Bibiana M. de Souza
    • 2
  • Mario S. Palma
    • 2
  • Maria Alice da Cruz-Höfling
    • 1
  • John Buchanan Harris
    • 3
  1. 1.Department of Histology and EmbryologyInstitute of Biology, University of Campinas, UNICAMPCampinasBrazil
  2. 2.Department of BiologyInstitute of Biosciences, Center of Studies of Social Insects, São Paulo State University, UNESPRio ClaroBrazil
  3. 3.Medical Toxicology Centre, Institute of Neuroscience, The Medical SchoolNewcastle UniversityNewcastle upon TyneUK