scholarly journals Acute Ethanol Exposure Elevates Muscarinic Tone in the Septohippocampal System

2010 ◽  
Vol 103 (1) ◽  
pp. 290-296 ◽  
Author(s):  
Mia Ericson ◽  
Michelle A Sama ◽  
Hermes H. Yeh
Keyword(s):  
Direct Action ◽  
Cholinergic Neurons ◽  
Medial Septum ◽  
Ethanol Exposure ◽  
Neuronal Firing ◽  
Firing Activity ◽  
Diagonal Band ◽  
Acute Ethanol ◽  
Septohippocampal System ◽  
Methyl Scopolamine

The septohippocampal system has been implicated in the cognitive deficits associated with ethanol consumption, but the cellular basis of ethanol action awaits full elucidation. In the medial septum/diagonal band of Broca (MS/DB), a muscarinic tone, reflective of firing activity of resident cholinergic neurons, regulates that of their noncholinergic, putatively GABAergic, counterparts. Here we tested the hypothesis that ethanol alters this muscarinic tone. The spontaneous firing activity of cholinergic and noncholinergic MS/DB neurons were monitored in acute MS/DB slices from C57Bl/6 mice. Exposing the entire slice to ethanol increased firing in both cholinergic and noncholinergic neurons. However, applying ethanol focally to individual MS/DB neurons increased firing only in cholinergic neurons. The differential outcome suggested different mechanisms of ethanol action on cholinergic and noncholinergic neurons. Indeed, with bath-perfused ethanol, the muscarinic antagonist methyl scopolamine prevented the increase in firing in noncholinergic, but not cholinergic, MS/DB neurons. Thus, the effect on noncholinergic neuronal firing was secondary to ethanol's direct action of acutely increasing muscarinic tone. We propose that the acute ethanol-induced elevation of muscarinic tone in the MS/DB contributes to the altered net flow of neuronal activity in the septohippocampal system that underlies compromised cognitive function.

scholarly journals The endomembrane system of cholinergic and non-cholinergic neurons in the medial septal nucleus and vertical limb of the diagonal band of Broca: a cytochemical and immunocytochemical study.

1990 ◽  
Vol 38 (4) ◽  
pp. 563-571 ◽  
Author(s):  
G Palacios
Keyword(s):  
Cholinergic Neurons ◽  
Medial Septum ◽  
Projection Neurons ◽  
Lamellar Bodies ◽  
Endomembrane System ◽  
Electron Microscopic ◽  
Diagonal Band ◽  
Diagonal Band Of Broca ◽  
Well Differentiated ◽  
Microscopic Morphology

Coronal vibratome sections of the rostral part of the medial septum (MS) and vertical limb of the diagonal band of Broca (VDB) nuclei were studied by an immunocytochemical technique using a monoclonal antibody against choline acetyltransferase (ChAT) and a double histochemical method for detection of acid phosphatase (AcPase) and nucleoside diphosphatase (NDPase) activity. The electron microscopic morphology of ChAT-immunoreactive and non-immunoreactive neurons was compared with similar neurons showing both AcPase and NDPase activity. ChAT-labeled and non-labeled neurons were well differentiated by the organization of the endomembrane system and especially by the structure of the rough endoplasmic reticulum (RER) and associated lamellar bodies. These results support the theory that the peculiar ultrastructure of the lamellar bodies in each neuron is related to the pattern of organization of the endomembrane system and its function. The significance of the lamellar bodies is discussed, and the data of the present work, together with findings described by other investigators. These data suggest that these bodies are predominant in efferent projection neurons in the basal forebrain nuclei.

Effects of Neonatal Ethanol Exposure on Cholinergic Neurons of the Rat Medial Septum

Alcohol ◽  
1998 ◽  
Vol 15 (3) ◽  
pp. 219-226 ◽  
Author(s):  
D.Blaine Moore ◽  
Pamela Lee ◽  
Michael Paiva ◽  
Don W Walker ◽  
Marieta Barrow Heaton
Keyword(s):  
Cholinergic Neurons ◽  
Medial Septum ◽  
Ethanol Exposure

scholarly journals Septal cholinergic input to CA2 hippocampal region controls social novelty discrimination via nicotinic receptor-mediated disinhibition

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Domenico Pimpinella ◽  
Valentina Mastrorilli ◽  
Corinna Giorgi ◽  
Silke Coemans ◽  
Salvatore Lecca ◽  
...  
Keyword(s):  
Social Memory ◽  
Ex Vivo ◽  
Hippocampal Slices ◽  
Cholinergic Neurons ◽  
Underlying Mechanism ◽  
Medial Septum ◽  
Principal Cells ◽  
Diagonal Band ◽  
Social Novelty Discrimination

Acetylcholine (ACh), released in the hippocampus from fibers originating in the medial septum/diagonal band of Broca (MSDB) complex, is crucial for learning and memory. The CA2 region of the hippocampus has received increasing attention in the context of social memory. However, the contribution of ACh to this process remains unclear. Here, we show that in mice, ACh controls social memory. Specifically, MSDB cholinergic neurons inhibition impairs social novelty discrimination, meaning the propensity of a mouse to interact with a novel rather than a familiar conspecific. This effect is mimicked by a selective antagonist of nicotinic AChRs delivered in CA2. Ex vivo recordings from hippocampal slices provide insight into the underlying mechanism, as activation of nAChRs by nicotine increases the excitatory drive to CA2 principal cells via disinhibition. In line with this observation, optogenetic activation of cholinergic neurons in MSDB increases the firing of CA2 principal cells in vivo. These results point to nAChRs as essential players in social novelty discrimination by controlling inhibition in the CA2 region.

scholarly journals Estimation of the Total Number of Cholinergic Neurons Containing Estrogen Receptor-α in the Rat Basal Forebrain

2002 ◽  
Vol 50 (7) ◽  
pp. 891-902 ◽  
Author(s):  
Riitta A. Miettinen ◽  
Giedrius Kalesnykas ◽  
Esa H. Koivisto
Keyword(s):  
Estrogen Receptor ◽  
Basal Forebrain ◽  
Cholinergic Neurons ◽  
Estrogen Receptor Α ◽  
Medial Septum ◽  
Nucleus Basalis ◽  
Cell Counting ◽  
Double Immunostaining ◽  
Diagonal Band ◽  
Diagonal Band Of Broca

This study was undertaken to estimate the total number of cholinergic cells and the percentage of cholinergic cells that contain estrogen receptor-α (ERα) in the rat basal forebrain. Double immunostaining for choline acetyltransferase (ChAT) and ERα was carried out on 50-μm-thick free-floating sections. Because routine mounting method causes considerable flattening of the sections, we embedded immunostained sections in Durcupan, an epoxy resin known to cause virtually no shrinkage. When this procedure was used the section thickness was well preserved, individual cells could be clearly identified, and subcellular localization of ERα immunoreactivity was easy to verify. Cell counting in these sections revealed that the rat basal forebrain contains 26,390 ± 1097 (mean ± SEM) cholinergic neurons. This comprises 9674 ± 504 in the medial septum-vertical diagonal band of Broca, 9403 ± 484 in the horizontal diagonal band of Broca, and 7312 ± 281 in the nucleus basalis. In these nuclei, 60%, 46%, and 14% of the cholinergic neurons were colocalized with ERα, respectively. We believe that our results are an improvement on existing data because of the better distinction of individual neurons that the Durcupan embedding method brings.

Development of GABAA receptors on medial septum/diagonal band (MS/DB) neurons after postnatal ethanol exposure

1998 ◽  
Vol 810 (1-2) ◽  
pp. 100-113 ◽  
Author(s):  
Shu-Huei Hsiao ◽  
Jolonda C Mahoney ◽  
James R West ◽  
Gerald D Frye
Keyword(s):  
Gabaa Receptors ◽  
Medial Septum ◽  
Ethanol Exposure ◽  
Diagonal Band
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