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Neuropeptide Y receptors differentially modulate G‐protein‐activated inwardly rectifying K + channels and high‐voltage‐activated Ca 2+ channels in rat thalamic neurons
Author(s) -
Sun QianQuan,
Huguenard John R.,
Prince David A.
Publication year - 2001
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2001.0067j.x
Subject(s) - g protein coupled inwardly rectifying potassium channel , chemistry , neuropeptide y receptor , patch clamp , receptor , biophysics , g protein , medicine , endocrinology , neuropeptide , neuroscience , biology , biochemistry
1 Using whole‐cell patch‐clamp recordings, infrared videomicroscopy and fast focal solution exchange methods, the actions of neuropeptide Y (NPY) were examined in thalamic slices of postnatal (10‐16 days) rats. 2 NPY activated a K + ‐selective current in neurons of the thalamic reticular nucleus (RT; 20/29 neurons) and ventral basal complex (VB; 19/25 neurons). The currents in both nuclei had activation and deactivation kinetics that were very similar to those of GABA B receptor‐induced currents, were totally blocked by 0.1 mM Ba 2+ and showed voltage‐dependent relaxation. These properties indicate that the NPY‐sensitive K + current is mediated by G‐protein‐activated, inwardly rectifying K + (GIRK) channels. 3 In RT neurons, NPY application reversibly reduced high‐voltage‐activated (HVA) currents to 33 ± 5 % ( n = 40 ) of the control level but did not affect the T‐type currents. Inhibition of Ca 2+ currents was voltage independent and was largely mediated by effects on N‐ and P/Q‐type channels. 4 NPY activation of GIRK channels was mediated via NPY 1 receptors, whereas inhibition of N‐ and P/Q‐type Ca 2+ channels was mediated by NPY 2 receptors. 5 These results show that neuropeptide Y activates K + channels and simultaneously inhibits HVA Ca 2+ channels via different receptor subtypes.