Phospholipase A2-induced neurotoxicity in vitro and in vivo in rats

L. E. Clapp, K. L. Klette, M. A. DeCoster, E. Bernton, J. M. Petras, J. R. Dave, M. S. Laskosky, R. C. Smallridge, F. C. Tortella

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32 Scopus citations


The present study evaluated the neurotoxic potential of phospholipase A2 (PLA2) in vitro (primary neuronal cultures) and in vivo (EEG and behavior) rat models of CNS excitability. In vitro, PLA2 (0.0038-5.8 nM) or melittin (a potent activator of endogenous PLA2; 100-5000 nM), were highly neurotoxic, causing approximately 500 units/ml LDH release. The neurotoxic EC50s for PLA2 and melittin were 1.8 (1.4-2.3) and 848 (501-1280) nM, respectively. Neurotoxic concentrations of PLA2 stimulated neuronal release of [3H]AA. Preliminary in vitro experiments evaluating changes in neuronal calcium flux indicated that PLA2 caused transient, and melittin sustained, increases in [Ca2+]i. In vivo, PLA2 (0.5-5 μg i.c.v.) or melittin (2.5-20 μg i.c.v.) produced nonconvulsive EEG seizures, which generalized to status epilepticus. While the onset of seizure development was markedly delayed for PLA2 (1.5-4.5 h), the seizure inducing effects of melittin were evident within 3.5 ± 0.2 min and more severe. Both PLA2 and melittin were lethal, exhibiting LD50s of 0.62 μg and 8.4 μg, respectively. Pretreatment with (+)-MK801 (5 μg, i.c.v.) significantly attenuated melittin, but not PLA2, in vivo neurotoxicity. PLA2 induced neuropathology in surviving rats revealed extensive cortical and subcortical injury to forebrain neurons and fibre pathways. Collectively, these results demonstrate the potent neurotoxic potential of PLA2, the delayed clinical nature of its in vivo neurotoxicity and the applicability of these model systems to future studies on mechanisms of PLA2 neurotoxicity and the development of potential PLA2 antagonists.

Original languageEnglish (US)
Pages (from-to)101-111
Number of pages11
JournalBrain Research
Issue number1-2
StatePublished - Sep 25 1995


  • Melittin
  • Neuronal culture
  • Neurotoxicity
  • Phospholipase A
  • Rat
  • Seizure
  • [Ca]

ASJC Scopus subject areas

  • General Neuroscience
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology


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