A brief, but repeated, swimming protocol is sufficient to overcome amyloid beta-protein inhibition of hippocampal long-term potentiation

Eur J Neurosci. 2007 Sep;26(5):1289-98. doi: 10.1111/j.1460-9568.2007.05760.x.

Abstract

Alzheimer's disease starts as an almost imperceptible malady, first observed clinically as a mild memory problem. Accumulating genetic and biochemical data have suggested that amyloid beta-protein (Abeta) plays an important role in this memory loss, and Abeta has been shown to suppress long-term potentiation (LTP), a cellular model for memory and learning. Here we show that a very brief (3 min) swimming, twice daily for 2 weeks, rescues LTP inhibition in the CA1 region of hippocampal slices caused by Abeta(42) or Abeta(40) carrying the Arctic mutation using a theta burst stimulation (TBS) protocol. Whereas the input-output curve was not affected, the paired-pulse ratio was reduced in mice receiving our repeated swimming protocol, suggesting a possible involvement of presynaptic facilitation. Similar to swimming, Abeta's inhibition of LTP could be rescued with the adenylyl cyclase, forskolin. Interestingly, this swimming protocol produced conditions in which a weak-TBS could invoke LTP not observed in naïve mice, which again was mimicked by forskolin. In contrast, the protein kinase A (PKA) inhibitor, H89, blocked both the forskolin and swimming potentiation of LTP; these data implicate cAMP/PKA signaling in the protective effect of swimming and mediating Abeta' detrimental effects. Our data add a new simple behavior paradigm that shows the importance of an environmental factor in reversing the pathophysiological effects of Abeta, and suggest new therapeutic avenues.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Peptides / pharmacology*
  • Animals
  • Animals, Newborn
  • Behavior, Animal
  • Colforsin / pharmacology
  • Dose-Response Relationship, Immunologic
  • Electric Stimulation / methods
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • Excitatory Postsynaptic Potentials / radiation effects
  • Female
  • Hippocampus / drug effects*
  • In Vitro Techniques
  • Isoquinolines / pharmacology
  • Long-Term Potentiation / drug effects*
  • Long-Term Potentiation / physiology
  • Long-Term Potentiation / radiation effects
  • Male
  • Mice
  • Neural Inhibition / drug effects*
  • Neural Inhibition / physiology*
  • Peptide Fragments / pharmacology*
  • Protein Kinase Inhibitors / pharmacology
  • Sulfonamides / pharmacology
  • Swimming*
  • Time Factors

Substances

  • Amyloid beta-Peptides
  • Isoquinolines
  • Peptide Fragments
  • Protein Kinase Inhibitors
  • Sulfonamides
  • amyloid beta-protein (1-40)
  • Colforsin
  • N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide