title: Muscarinic receptor control of pyramidal neuron membrane potential in the medial prefrontal cortex (mPFC) in rats.
abstract: Damage to the cholinergic input to the prefrontal cortex has been implicated in neuropsychiatric disorders. Cholinergic endings release acetylcholine, which activates nicotinic and/or G-protein-coupled muscarinic receptors. Muscarinic receptors activate transduction systems, which control cellular effectors that regulate the membrane potential in medial prefrontal cortex (mPFC) neurons. The mechanisms responsible for the cholinergic-dependent depolarization of mPFC layer V pyramidal neurons in slices obtained from young rats were elucidated in this study. Glutamatergic and GABAergic transmission as well as tetrodotoxin (TTX)-sensitive Na(+) and voltage-dependent Ca(++) currents were eliminated. Cholinergic receptor stimulation by carbamoylcholine chloride (CCh; 100 μM) evoked depolarization (10.0 ± 1.3 mV), which was blocked by M1/M4 (pirenzepine dihydrochloride, 2 μM) and M1 (VU 0255035, 5 μM) muscarinic receptor antagonists and was not affected by a nicotinic receptor antagonist (mecamylamine hydrochloride, 10 μM). CCh-dependent depolarization was attenuated by extra- (20 μM) or intracellular (50 μM) application of an inhibitor of the βγ-subunit-dependent transduction system (gallein). It was also inhibited by intracellular application of a βγ-subunit-binding peptide (GRK2i, 10μM). mPFC pyramidal neurons express Nav1.9 channels. CCh-dependent depolarization was abolished in the presence of antibodies against Nav1.9 channels in the intracellular solution and augmented by the presence of ProTx-I toxin (100 nM) in the extracellular solution. CCh-induced depolarization was not affected by the following reagents: intracellular transduction system blockers, including U-73122 (10 μM), chelerythrine chloride (5 μM), SQ 22536 (100 μM) and H-89 (2 μM); channel blockers, including Ba(++) ions (200 μM), apamin (100 nM), flufenamic acid (200 μM), 2-APB (200 μM), SKF 96365 (50 μM), and ZD 7288 (50 μM); and a Na(+)/Ca(++) exchanger blocker, benzamil (20 μM). We conclude that muscarinic M1 receptor-dependent depolarization in mPFC pyramidal neurons is evoked by the activation of Nav1.9 channels and that the signal transduction pathway involves G-protein βγ subunits.
authors.affiliation: Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, The Medical University of Warsaw, Banacha 1B, Warsaw 02-097, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Kurowski
authors.affiliation: Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, The Medical University of Warsaw, Banacha 1B, Warsaw 02-097, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Gawlak
authors.affiliation: Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, The Medical University of Warsaw, Banacha 1B, Warsaw 02-097, Poland. Electronic address: pawel.szulczyk@wum.edu.pl.
authors.forename: P
authors.initials: P
authors.lastname: Szulczyk
mesh_terms: D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001030:Apamin / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology; D004347:Drug Interactions; D005727:Ganglia, Spinal / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D062558:NAV1.9 Voltage-Gated Sodium Channel / Q000378:metabolism; D017397:Prefrontal Cortex / Q000166:cytology*; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011976:Receptors, Muscarinic / Q000378:metabolism*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D013830:Thiadiazoles / Q000494:pharmacology; D014966:Xanthenes / Q000494:pharmacology
chemical_list: D018679:Cholinergic Agonists; C542801:N-(3-oxo-3-(4-(pyridin-4-yl)piperazin-1-yl)propyl)benzo(c)(1,2,5)thiadiazole-4-sulfonamide; D062558:NAV1.9 Voltage-Gated Sodium Channel; D011976:Receptors, Muscarinic; C113705:Scn11a protein, rat; D026941:Sodium Channel Blockers; D013449:Sulfonamides; D013830:Thiadiazoles; D014966:Xanthenes; C013407:benzamil; D001030:Apamin; D013779:Tetrodotoxin; D000584:Amiloride; C007820:gallein; D002217:Carbachol
keywords: Nav1.9 channels; muscarinic receptors; prefrontal cortex; pyramidal neurons; rats; βγ subunits