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Functional nicotinic ACh receptors on interneurones in the rat hippocampus
Author(s) -
Jones Susan,
Yakel Jerrel L.
Publication year - 1997
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.1469-7793.1997.603bd.x
Subject(s) - methyllycaconitine , mecamylamine , nicotinic agonist , neuroscience , dentate gyrus , nicotinic antagonist , inhibitory postsynaptic potential , hippocampus , acetylcholine , hippocampal formation , chemistry , muscarinic acetylcholine receptor , excitatory postsynaptic potential , acetylcholine receptor , neurotransmission , nicotinic acetylcholine receptor , biophysics , biology , receptor , pharmacology , biochemistry
1 Neuronal nicotinic ACh receptors (nAChRs) were studied in the rat hippocampal slice preparation using whole‐cell patch‐clamp recording techniques. 2 Responses to ACh (100 μ m ) were detected on inhibitory interneurones in the CA1 field of the hippocampus proper and in the dentate gyrus, but not on principal excitatory neurones in either region. The different neuronal types were identified based on their morphology and location. 3 ACh excited interneurones in the hippocampus and dentate gyrus in current‐clamp recordings. In voltage‐clamp recordings, ACh‐activated inward currents were recorded from interneurones in the presence of blockers of synaptic transmission and the muscarinic ACh receptor antagonist atropine. The zero current potential for this response to ACh was near 0 mV. 4 The effect of ACh was mimicked by the nAChR‐selective agonists nicotine (100 μ m ) and 1,1‐dimethyl‐4‐phenyl‐piperazinium iodide (DMPP, 100 μ m ). The response to ACh was reversibly antagonized by the neuronal nAChR antagonist mecamylamine (10 μ m ). The nAChR α7 subunit‐selective antagonists α‐bungarotoxin (100 n m ) and methyllycaconitine (10 n m ) also inhibited the response to ACh. 5 These observations demonstrate the presence of functional nAChRs on inhibitory interneurones in the rat hippocampus. Thus, a novel mechanism by which ACh can regulate neuronal activity in the hippocampus is revealed.