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Neurotensin facilitates GABA release in rat hippocampus
Author(s) -
Li shanshan,
Lei Saobo
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a243
Subject(s) - afterhyperpolarization , neurotensin , neuroscience , hippocampus , gabaergic , hippocampal formation , chemistry , charybdotoxin , neurotransmission , inhibitory postsynaptic potential , biophysics , biology , endocrinology , receptor , neuropeptide , membrane potential , biochemistry
Neurotensin (NT) and NT receptors are expressed in multiple brain regions including the hippocampus. However, the functions of NT in the hippocampus have not been determined. We examined the effects of NT on GABAergic synaptic transmission in the hippocampus. Our results demonstrate that NT increased the frequency of sIPSCs recorded from CA1 pyramidal neurons without significantly altering sIPSC amplitude. NT did not change mIPSCs recorded in the presence of TTX nor did it alter the evoked IPSCs. NT also increased the firing frequency of spontaneous action potentials recorded from the interneurons in the stratum radiatum of CA1 region suggesting that NT acts by enhancing the excitability of interneurons to increase GABA release. NT failed to change the holding current recorded at ‐50 mV suggesting that NT is unlikely to increase action potential firing frequency by facilitating the resting K + conductance of the interneurons. Analysis of the action potential shape indicated that NT decreased the amplitude of afterhyperpolarization suggesting that NT inhibits Ca 2+ ‐activated K + channels (I K , Ca ). NT‐induced increases in sIPSC frequency were inhibited by the I K,Ca inhibitor, charybdotoxin, suggesting that the large conductance I K,Ca are involved. Our study provides a cellular basis to explain the functions of NT in the brain. (Supported by COBRE/NIH).