Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5737869 | Neuroscience | 2017 | 11 Pages |
Abstract
The intergeniculate leaflet (IGL) is a flat thalamic nucleus implicated in the modulation of circadian rhythmicity. In rat, two main GABAergic subpopulations can be distinguished in the IGL: neurons synthesizing neuropeptide Y (NPY), which directly innervates the suprachiasmatic nuclei, and enkephalinergic cells, which connect contralaterally located leaflets. The aim of this study was to evaluate possible effects of inner IGL neurotransmitters on the spontaneous and synaptic activity of IGL neurons. The data presented in this article provide evidence that enkephalin, and not NPY, could act upon the majority of IGL neurons. Moreover, we investigated the type of opioid receptor activated by enkephalin and showed that the μ-receptor is functionally predominant in the IGL. The application of met-enkephalin not only robustly hyperpolarized IGL neurons (both putatively NPY-synthesizing and putatively enkephalinergic neurons), but it also was able to inhibit GABAergic and glutamatergic synaptic transmission. Based on this and previous studies, we hypothesize that IGL enkephalinergic neurons may act as powerful interneurons that inhibit themselves and NPY-synthesizing neurons, also in the contralaterally located IGL.
Keywords
nAXGGTTTXAP-5SCNmEPSCMet-enkephalinaCSFNPYNALmIPSCEGTAA-type potassium currentBICT-type calcium currentHEPEStetrodotoxin citrate2-amino-5-phosphonopentanoic acid4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid6-Cyano-7-nitroquinoxaline-2,3-dioneethylene glycol tetraacetic acidγ-aminobutyric acidsynaptic transmissionstandard deviationEnkenkephalinISOIGLminiature inhibitory postsynaptic currentminiature excitatory postsynaptic currentintergeniculate leafletstandard error of the meanZeitgeber timeCNQXartificial cerebro-spinal fluidbicuculline methiodideSEMSuprachiasmatic nucleusPatch clampGABANeuropeptide Y
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Authors
K. Palus, L. Chrobok, M. Kepczynski, M.H. Lewandowski,