Cholinergic nerve terminals establish classical synapses in the rat cerebral cortex: synaptic pattern and age-related atrophy

Turrini, Paolo; Casu, Maria Antonietta; Wong, Tak Pan; Ribeiro‐da‐Silva, Alfredo; Cuello, A. Claudio

doi:10.1016/s0306-4522(01)00172-5

Cited by 131 publications

(84 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Scale bar: 5 m. figured in conventional PSDs but rather are more distributed and respond to agonist supplied more diffusely. This would be consistent with suggestions that cholinergic innervation in the CNS, such as that provided by the septal input to the hippocampus, may be diffuse, delivering ACh at a distance for "volume transmission" (McKinney et al, 1983;Frotscher and Leranth, 1985;Descarries et al, 1997;Descarries, 1998;Zoli et al, 1999; but see Turrini et al, 2001). Because ␣7-nAChRs can also respond to choline as an agonist (Papke et al, 1996;Alkondon et al, 1997b), hydrolysis of ACh by extracellular acetylcholinesterase need not prevent distally released agonist from affecting the receptors.…”

Section: Postsynaptic/perisynaptic Sitessupporting

confidence: 81%

Nicotinic α7 receptors: Synaptic options and downstream signaling in neurons

2002

View full text Add to dashboard Cite

Nicotinic receptors are cation-ion selective ligand-gated ion channels that are expressed throughout the nervous system. Most have significant calcium permeabilities, enabling them to regulate calcium-dependent events. One of the most abundant is a species composed of the ␣7 gene product and having a relative calcium permeability equivalent to that of NMDA receptors. The ␣7-containing receptors can be found presynaptically where they modulate transmitter release, and postsynaptically where they generate excitatory responses. They can also be found in perisynaptic locations where they modulate other inputs to the neuron and can activate a variety of downstream signaling pathways. The effects the receptors produce depend critically on the sites at which they are clustered. Instructive preparations for examining ␣7-containing receptors are the rat hippocampus, where they are thought to play a modulatory role, and the chick ciliary ganglion, where they participate in throughput transmission as well as regulatory signaling. Relatively high levels of ␣7-containing receptors are found in the two preparations, and the receptors display a variety of synaptic options and functions in the two cases. Progress is starting to be made in understanding the mechanisms responsible for localizing the receptors at specific sites and in identifying components tethered in the vicinity of the receptors that may facilitate signal transduction and downstream signaling.

show abstract

Section: Postsynaptic/perisynaptic Sitessupporting

confidence: 81%

Nicotinic α7 receptors: Synaptic options and downstream signaling in neurons

2002

View full text Add to dashboard Cite

show abstract

“…Some studies reported that the significant part of cholinergic varicosities form conventional synapses with dendritic shafts and spines (Frotscher and Leranth, 1985;Smiley et al, 1997;Turrini et al, 2001), while others described the low incidence of synaptic specializations (Aoki and Kabak, 1992;Chedotal et al, 1994;Umbriaco et al, 1994Umbriaco et al, , 1995Vaucher and Hamel, 1995;Mechawar et al, , 2002. We revisited this issue by investigating the presence or absence of synapse-like specializations, including parallel membrane apposition of cholinergic varicosities and other neuronal elements, uniform cleft width between the apposed membranes, and thickening of the apposed membranes.…”

Section: Cholinergic Varicosities Rarely Make "Classical" Synapsesmentioning

confidence: 99%

“…Volume transmission is inferred from observations that cholinergic fibers are diffuse and rough in topographical organization (Zaborszky et al, 1999), are distributed at much lower densities than ACh receptor binding sites (reviewed by Herkenham, 1987), and make synaptic specialization only infrequently (Chedotal et al, 1994;Umbriaco et al, 1994Umbriaco et al, , 1995Vaucher and Hamel, 1995;Mechawar et al, 2000Mechawar et al, , 2002 for review, see Descarries and Mechawar, 2000). On the other hand, the possibility that the signaling mode is more specific than volume transmission is also suggested from phasic ACh rise in the prefrontal cortex of taskperforming rats (Parikh et al, 2007), transient mAChR-mediated modulation of cortical pyramidal cells (Gulledge and Stuart, 2005;Gulledge et al, 2009), and formation of "conventional" synapses by cholinergic fibers (Frotscher and Leranth, 1985;Smiley et al, 1997;Turrini et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Preferential Localization of Muscarinic M₁Receptor on Dendritic Shaft and Spine of Cortical Pyramidal Cells and Its Anatomical Evidence for Volume Transmission

Yamasaki¹,

Matsui²,

Watanabe³

2010

J. Neurosci.

188

176

View full text Add to dashboard Cite

Acetylcholine (ACh) plays important roles for higher brain functions, including arousal, attention, and cognition. These effects are mediated largely by muscarinic acetylcholine receptors (mAChRs). However, it remains inconclusive whether the mode of ACh-mAChR signaling is synaptic, so-called "wired," transmission mediated by ACh released into the synaptic cleft, or nonsynaptic, so-called "volume," transmission by ambient ACh. To address this issue, we examined cellular and subcellular distribution of M 1 , the most predominant mAChR subtype in the cerebral cortex and hippocampus, and pursued its anatomical relationship with cholinergic varicosities in these regions of adult mice. M 1 was highly expressed in glutamatergic pyramidal neurons, whereas it was low or undetectable in various GABAergic interneuron subtypes. M 1 was preferentially distributed on the extrasynaptic membrane of pyramidal cell dendrites and spines. Cholinergic varicosities often made direct contact to pyramidal cell dendrites and synapses. At such contact sites, however, synapse-like specialization was infrequent, and no particular accumulation was found at around contact sites for both M 1 and presynpatic active zone protein Bassoon. These features contrasted with those of the glutamatergic system, in which AMPA receptor GluA2 and metabotropic receptor mGluR5 were recruited to the synaptic or perisynaptic membrane, respectively, and Bassoon was highly accumulated in the presynaptic terminals. These results suggest that M 1 is so positioned to sense ambient ACh released from cholinergic varicosities at variable distances, and to enhance the synaptic efficacy and excitability of pyramidal cells. These molecular-anatomical arrangements will provide the evidence for volume transmission, at least in M 1 -mediated cortical cholinergic signaling.

show abstract

“…4.5 Ionic currents. Potassium (K + ) and Sodium (Na ++ ) currents I k and I Na in (1) are derived from Traub and Miles (2001), and are described as: (26) neurons (McCormick and Prince, 1985), and rat cortical layer 5 cells seem to be a preferential target for cholinergic innervation (Turrini et al, 2001). The known electrophysiological excitatory action is thought to be mediated by binding of ACh to muscarinic and/or nicotinic receptors on pyramidal neurons.…”

Section: Neurotransmitter Releasementioning

confidence: 99%