Facilitated induction of hippocampal long-term potentiation in slices perfused with low concentrations of magnesium.
The generation of long-term potentiation of synaptic transmission in area CA1 of hippocampal slices of the guinea-pig has been examined in solutions containing low concentrations of magnesium ions. It was found that the induction of long-term potentiation is greatly facilitated in slices perfused with 0.1 mM magnesium but much less so with 0.5 mM magnesium solution. The long-term potentiation evoked by brief tetanization in 0.1 mM magnesium was prevented following application of the N-methyl-D-aspartate receptor antagonist 2-amino-5-phosphonovalerate. Moreover, the response to tetanization, recorded in the dendritic layer, contained a much greater than normal component blocked by 2-amino-5-phosphonovalerate. The latter represents current through postsynaptic N-methyl-D-aspartate receptor channels, suggesting that the facilitation of long-term potentiation is related to a facilitated opening of these channels. The results support the notion that the generation of long-term potentiation is related to current through N-methyl-D-aspartate receptor channels which is under the control of extracellular magnesium ions.
D015763:2-Amino-5-phosphonovalerate; D000818:Animals; D046508:Culture Techniques; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D006168:Guinea Pigs; D006624:Hippocampus / Q000502:physiology*; D008274:Magnesium / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D015763:2-Amino-5-phosphonovalerate; D014633:Valine; D008274:Magnesium