Spermine and philanthotoxin potentiate excitatory amino acid responses of Xenopus oocytes injected with rat and chick brain RNA

Neurosci Lett. 1990 Jun 22;114(1):51-6. doi: 10.1016/0304-3940(90)90427-b.

Abstract

The effects of spermine and a synthetic analogue (PhTX-343) of the polyamine amide toxin, delta-philanthotoxin, on the responses of Xenopus oocytes to application of amino acids were examined using voltage clamp. The oocytes were injected with either total rat brain RNA or chick cerebrum, poly(A+)RNA. The responses to N-methyl-D-aspartate and L-kainate were potentiated by low concentrations (10(-11)-10(-7) M) of PhTX-343 and by 10(-5)-10(-4) M spermine. There was variability between oocytes in terms of their responsiveness to these compounds and recovery from their effects was slow and often incomplete. Prolonged or repeated applications of PhTX-343 and spermine eventually resulted in inhibition. Higher concentrations of these compounds always inhibited the responses to acidic amino acids. Low concentrations of PhTX-343 and spermine also potentiated the responses to nicotine and gamma-aminobutyric acid. These results are discussed in terms of the postulated polyamine binding site on the N-methyl-D-aspartate receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / pharmacology*
  • Animals
  • Aspartic Acid / analogs & derivatives
  • Aspartic Acid / pharmacology
  • Bee Venoms / pharmacology*
  • Brain / physiology*
  • Chickens
  • Kainic Acid / pharmacology
  • Male
  • Membrane Potentials / drug effects
  • Microinjections
  • N-Methylaspartate
  • Neurotoxins / pharmacology*
  • Oocytes / drug effects
  • Oocytes / physiology*
  • Oxadiazoles / pharmacology
  • Poly A / administration & dosage
  • Poly A / genetics
  • Polyamines*
  • Quisqualic Acid
  • RNA / administration & dosage
  • RNA / genetics*
  • RNA, Messenger
  • Rats
  • Rats, Inbred Strains
  • Spermine / physiology*
  • Wasp Venoms / pharmacology*
  • Xenopus

Substances

  • Amino Acids
  • Bee Venoms
  • Neurotoxins
  • Oxadiazoles
  • Polyamines
  • RNA, Messenger
  • Wasp Venoms
  • Poly A
  • Spermine
  • Aspartic Acid
  • RNA
  • N-Methylaspartate
  • delta-philanthotoxin
  • Quisqualic Acid
  • Kainic Acid