Presynaptic glycine receptors on hippocampal mossy fibers.
Presynaptic glycine receptors (GlyRs) have been implicated in the regulation of glutamatergic synaptic transmission. Here, we characterized presynaptic GlyR-mediated currents by patch-clamp recording from mossy fiber boutons (MFBs) in rat hippocampal slices. In MFBs, focal puff-application of glycine-evoked chloride currents that were blocked by the GlyR antagonist strychnine. Their amplitudes declined substantially during postnatal development, from a mean conductance per MFB of approximately 600 pS in young to approximately 130 pS in adult animals. Single-channel analysis revealed multiple conductance states between approximately 20 and approximately 120 pS, consistent with expression of both homo- and hetero-oligomeric GlyRs. Accordingly, estimated GlyRs densities varied between 8-17 per young, and 1-3 per adult, MFB. Our results demonstrate that functional presynaptic GlyRs are present on hippocampal mossy fiber terminals and suggest a role of these receptors in the regulation of glutamate release during the development of the mossy fiber--CA3 synapse.
Kubota
Hisahiko
H
Independent Hertie Research Group, Max-Planck Institute for Brain Research, D-60528 Frankfurt am Main, Germany.
Alle
Henrik
H
Betz
Heinrich
H
Geiger
Jörg R P
JR
D000818:Animals; D005998:Glycine / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects / Q000254:growth & development*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D018009:Receptors, Glycine / Q000378:metabolism / Q000502:physiology*; D017661:Receptors, Presynaptic / Q000378:metabolism / Q000502:physiology*; D013331:Strychnine / Q000494:pharmacology
D018009:Receptors, Glycine; D017661:Receptors, Presynaptic; D013331:Strychnine; D005998:Glycine