VIP enhances both pre- and postsynaptic GABAergic transmission to hippocampal interneurones leading to increased excitatory synaptic transmission to CA1 pyramidal cells.

Article date: 2004/10/27

PubMed ID: 603028

Journal name: British journal of pharmacology (ISSN: 0007-1188)


Vasoactive intestinal peptide (VIP) is present in the hippocampus in three subtypes of GABAergic interneurones, two of which innervate preferentially other interneurones, responsible for pyramidal cell inhibition. We investigated how pre- and postsynaptic modulation of GABAergic transmission (to both pyramidal cells and interneurones) by VIP could influence excitatory synaptic transmission in the CA1 area of the hippocampus. VIP (0.1-100 nM) increased [(3)H]GABA release from hippocampal synaptosomes (maximum effect at 1 nM VIP; 63.8 +/- 4.0%) but did not change [(3)H]glutamate release. VIP (0.3-30 nM) enhanced synaptic transmission in hippocampal slices (maximum effect at 1 nM VIP; field excitatory postsynaptic potentials (epsp) slope: 23.7 +/- 1.1%; population spike amplitude: 20.3 +/- 1.7%). The action on field epsp slope was fully dependent on GABAergic transmission since it was absent in the presence of picrotoxin (50 microM) plus CGP55845 (1 microM). VIP (1 nM) did not change paired-pulse facilitation but increased paired-pulse inhibition in CA1 pyramidal cells (16.0 +/- 0.9%), reinforcing the involvement of GABAergic transmission in the action of VIP. VIP (1 nM) increased muscimol-evoked inhibitory currents by 36.4 +/- 8.7% in eight out of ten CA1 interneurones in the stratum radiatum. This suggests that VIP promotes increased inhibition of interneurones that control pyramidal cells, leading to disinhibition of synaptic transmission to pyramidal cell dendrites. In conclusion, concerted pre- and postsynaptic actions of VIP lead to disinhibition of pyramidal cell dendrites causing an enhancement of synaptic transmission.

Author List: Cunha-Reis Diana, Sebasti√£o Ana M, Wirkner Kerstin, Illes Peter, Ribeiro Joaquim Alexandre

Publication Types: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't

Article Date: 2004/10/25

Substances mentioned in the article: Vasoactive Intestinal Peptide; gamma-Aminobutyric Acid;

Mesh terms: Animals; Excitatory Postsynaptic Potentials/drug effects; Hippocampus/drug effects; Interneurons/drug effects; Male; Presynaptic Terminals/drug effects; Pyramidal Cells/drug effects; Rats; Rats, Wistar; Synaptic Transmission/drug effects; Vasoactive Intestinal Peptide/pharmacology; gamma-Aminobutyric Acid/metabolism;

Citations: - 4296699

603028.txt · Last modified: 2018/11/20 14:25 (external edit)