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Metabotropic glutamate receptor agonist ACPD inhibits some, but not all, muscarinic‐sensitive K + conductances in basolateral amygdaloid neurons
Author(s) -
Womble Mark D.,
Moises Hylan C.
Publication year - 1994
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.890170202
Subject(s) - metabotropic receptor , chemistry , basolateral amygdala , neuroscience , metabotropic glutamate receptor , afterhyperpolarization , muscarinic acetylcholine receptor , depolarization , agonist , excitatory postsynaptic potential , biophysics , inhibitory postsynaptic potential , biology , receptor , biochemistry , amygdala
Muscarinic agonists produce membrane depolarization and losses of spike frequency accommodation and the slow afterhyperpolarization (AHP) when applied to neurons of the basolateral amygdala (BLA). Underlying these changes are the muscarinic‐induced inhibitions of several K + conductances, including the voltage‐activated M‐current (I M ), a slowly decaying Ca 2 ‐activated current (I AHP ), a voltage‐insensitive leak current (I Leak ), and the hyperpolarization‐activated inward rectifier current (I IR ) Similar depolarizations and losses of the slow AHP have been observed in other neuronal cell types following stimulation of metabotropic glutamate receptors. Therefore, we tested the effects of the metabotropic glutamate receptor agonist, 1‐aminocyclopentanels, 3r‐dicarboxylic acid (ACPD), on pyramidal neurons impaled with a single microelectrode for current‐ and voltage‐clamp recordings in a brain slice preparation of the rat BLA. Application of ACPD (20 or 100 μM) to BLA neurons inhibited I M and I A HP , resulting in membrane depolarization and reductions in the amplitude and duration of the slow AHP. However, ACPD did not inhibit the muscarinic‐sensitive current I IR , nor was I Leak blocked in the majority of neurons examined. These findings suggest the possibility that muscarinic cholinergic and metabotropic glutamatergic receptor agonists may activate separate intracellular transduction pathways which have convergent inhibitory effects onto I M and I AHP in BLA pyramidal neurons. © 1994 Wiley‐hiss, Inc.