Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Phasic cholinergic signaling in the hippocampus: Functional homology with the neocortex?

Phasic cholinergic signaling in the hippocampus: Functional homology with the neocortex? Acetylcholine (ACh) acts as a neurotransmitter in both the hippocampus and neocortex to facilitate learning, memory, and cognitive function. Here we show that transient muscarinic ACh receptor (mAChR) activation inhibits action potential generation in CA1, but not in CA3, pyramidal neurons via activation of an SK‐type calcium‐activated potassium conductance. Hyperpolarizing responses generated by focal ACh application near the somata of CA1 pyramidal neurons were blocked by atropine or the M1‐like mAChR antagonist pirenzepine, but not by the M2‐like mAChR antagonist methoctramine. Inhibitory cholinergic responses required intracellular calcium signaling, as evidenced by their sensitivity to depletion of internal calcium stores or internal calcium chelation. Cholinergic inhibition did not require GABAergic synaptic transmission, but was blocked by apamin, an SK channel antagonist. In contrast to inhibitory effects in CA1 neurons, ACh was primarily depolarizing, and enhanced action potential firing in CA3 pyramidal neurons. These results, when combined with recent data in neocortical neurons, suggest a functional homology in phasic cholinergic signaling in the hippocampus and neocortex whereby ACh preferentially inhibits those neurons in the lower cortical layers (CA1 and layer 5 neurons) that provide the majority of extracortical efferent projections. © 2007 Wiley‐Liss, Inc. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Hippocampus Wiley

Phasic cholinergic signaling in the hippocampus: Functional homology with the neocortex?

Hippocampus , Volume 17 (5) – Jan 1, 2007

Loading next page...
 
/lp/wiley/phasic-cholinergic-signaling-in-the-hippocampus-functional-homology-0r0J1HMamG

References (36)

Publisher
Wiley
Copyright
Copyright © 2007 Wiley Subscription Services
ISSN
1050-9631
eISSN
1098-1063
DOI
10.1002/hipo.20279
pmid
17407133
Publisher site
See Article on Publisher Site

Abstract

Acetylcholine (ACh) acts as a neurotransmitter in both the hippocampus and neocortex to facilitate learning, memory, and cognitive function. Here we show that transient muscarinic ACh receptor (mAChR) activation inhibits action potential generation in CA1, but not in CA3, pyramidal neurons via activation of an SK‐type calcium‐activated potassium conductance. Hyperpolarizing responses generated by focal ACh application near the somata of CA1 pyramidal neurons were blocked by atropine or the M1‐like mAChR antagonist pirenzepine, but not by the M2‐like mAChR antagonist methoctramine. Inhibitory cholinergic responses required intracellular calcium signaling, as evidenced by their sensitivity to depletion of internal calcium stores or internal calcium chelation. Cholinergic inhibition did not require GABAergic synaptic transmission, but was blocked by apamin, an SK channel antagonist. In contrast to inhibitory effects in CA1 neurons, ACh was primarily depolarizing, and enhanced action potential firing in CA3 pyramidal neurons. These results, when combined with recent data in neocortical neurons, suggest a functional homology in phasic cholinergic signaling in the hippocampus and neocortex whereby ACh preferentially inhibits those neurons in the lower cortical layers (CA1 and layer 5 neurons) that provide the majority of extracortical efferent projections. © 2007 Wiley‐Liss, Inc.

Journal

HippocampusWiley

Published: Jan 1, 2007

Keywords: ; ; ; ; ; ;

There are no references for this article.