Ryanodine produces a low frequency stimulation-induced NMDA receptor-independent long-term potentiation in the rat dentate gyrus in vitro

J Physiol. 1996 Sep 15;495 ( Pt 3)(Pt 3):755-67. doi: 10.1113/jphysiol.1996.sp021631.


1. The induction of long-term potentiation (LTP) was investigated in the rat dentate gyrus in the presence of ryanodine, an agent which is known to selectively bind to the ryanodine receptor (RyR) Ca2+ channels which regulate Ca2+ release from intracellular Ca2+ stores. 2. In control media, high frequency stimulation (HFS) induced LTP, and prolonged low frequency stimulation (LFS) induced long-term depression (LTD), of field excitatory postsynaptic potentials (EPSPs) and patch clamped excitatory postsynaptic currents (EPSCs). 3. In the presence of ryanodine, at a threshold concentration of about 1 microM, HFS-induced LTP was inhibited, whereas LFS (5 Hz, 900 pulses) now induced LTP. 4. The N-methyl-D-aspartate receptor (NMDAR) antagonist D-2-amino-phosphonopentanoate (D-AP5), at both 50 and 200 microM, did not prevent the induction of LTP by 5 Hz LFS in the presence of ryanodine. This demonstrates the NMDAR independence of LTP induction in the presence of ryanodine. Furthermore, D AP5 reversed the block of HFS-induced LTP by ryanodine. 5. The induction of LTP by 5 Hz LFS in the presence of ryanodine was blocked by lowering extracellular Ca2+, or by rapidly buffering intracellular Ca2+ to very low levels with BAPTA. 6. The induction of LTP by 5 Hz LFS was inhibited by the L-type voltage-gated Ca2+ channel blocker nifedipine, and also by Ni2+ a commonly used T type voltage-gated Ca2+ channel blocker. 7. The 5 Hz LFS-induced LTP in the presence of ryanodine was inhibited by the metabotropic glutamate receptor (mGluR) antagonist (+)-alpha-methyl 4-carboxyphenylglycine (MCPG). 8. The 5 Hz LFS-induced LTP in the presence of ryanodine was blocked by Ruthenium Red, an agent known to block RyR channel opening, and also by thapsigargin, an agent known to block-ATP-dependent Ca2+ uptake into endoplasmic reticulum. 9. The results of the present studies emphasize the importance of intracellular Ca2+ stores in the induction of LTP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Amino-5-phosphonovalerate / pharmacology
  • Animals
  • Calcium / metabolism
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / drug effects
  • Calcium Channels / metabolism
  • Chelating Agents / pharmacology
  • Dentate Gyrus / drug effects*
  • Dentate Gyrus / physiology*
  • Egtazic Acid / analogs & derivatives
  • Egtazic Acid / pharmacology
  • Electric Stimulation
  • Excitatory Amino Acid Antagonists / pharmacology
  • In Vitro Techniques
  • Long-Term Potentiation / drug effects*
  • Muscle Proteins / drug effects
  • Muscle Proteins / metabolism
  • Nickel / pharmacology
  • Nifedipine / pharmacology
  • Rats
  • Rats, Wistar
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Ruthenium Red / pharmacology
  • Ryanodine / pharmacology*
  • Ryanodine Receptor Calcium Release Channel
  • Thapsigargin / pharmacology


  • Calcium Channel Blockers
  • Calcium Channels
  • Chelating Agents
  • Excitatory Amino Acid Antagonists
  • Muscle Proteins
  • Receptors, N-Methyl-D-Aspartate
  • Ryanodine Receptor Calcium Release Channel
  • Ruthenium Red
  • Ryanodine
  • Egtazic Acid
  • Thapsigargin
  • 2-Amino-5-phosphonovalerate
  • Nickel
  • Nifedipine
  • 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
  • Calcium