Cholinergic neurons location

The development of antibodies against ChAT allowed the distribution of neurons producing acetylcholine in the nervous system to be revealed (Mesulam et al., 1983 Armstrong et al., 1983 Jones Beaudet, 1987 Vincent Reiner, 1987). In the context of control of wakefulness and REM sleep two groups of cholinergic neurons are of primary importance. Neurons located in the basal forebrain and medial septum provide the cholinergic innervation of the cerebral... 

Varicosity showing processes of synthesis and storage of acetylcholine within a cholinergic neuron. Also shown are the release of acetylcholine (exocytosis) and the location of acetylcholinesterase, which inactivates acetylcholine. 

The vagus nerve is a major connection between central and peripheral components. It contains both afferent (80%) and efferent (20%) pathways from and to the upper GIT. These include both cholinergic and non-cholinergic nerve fibres the non-cholinergic neurones may have serotonin as transmitter. Two types of vagal afferent receptors are involved in the emetic response (1) mechanoreceptors, iocated in the muscular wall of the distal stomach and proximal duodenum, which are activated by distension or contraction of the gut wall and (2) chemoreceptors located in the gut mucosa of the upper small bowel. These monitor the... 

The terminals of cholinergic neurons contain large numbers of small membrane-bound vesicles concentrated near the synaptic portion of the cell membrane (Figure 6-3) as well as a smaller number of large dense-cored vesicles located farther from the synaptic membrane. The large vesicles contain a high concentration of peptide cotransmitters (Table 6-1), while the smaller clear vesicles contain most of the acetylcholine. Vesicles are initially synthesized in the neuron soma and transported to the terminal. They may also be recycled several times within the terminal. 

The nucleus basalis of Meynert, located in the basal forebrain, is the main location of the cholinergic neurons. The cholinergic neurons project to the amygdala, hippocampus and other parts of the neocortex. Additional cholinergic neurons in the reticular system also project to the cerebral cortex, the limbic system, the hypothalamus, and the thalamus. Acetylcholine is... 

Since the somata of the great majority of cortical cholinergic fibres are located subcortically (Hebb et al., 1963 Krnjevic and Silver, 1965), stimulation of the surface will activate only the terminals orthodromically, while stimulation of the reticular formation activates the cholinergic fibres trans-synaptically (Szerb, 1967). Atropine approximately doubled the ACh release due to surface stimulation but increased 4-5 times ACh release resulting from reticular formation stimulation (Fig. 1). These results can be interpreted as follows for the full effect of atropine on ACh output it is necessary that the somata of cholinergic neurones be synaptically activated either... 

Szerb For this we would need to know where the somata of the cortical cholinergic neurones lie and there is some uncertainty about their anatomical location. Indications are that part of them are in the septum, at least in the cat. If you ask me whether we can block their inhibitory input directly, the answer is no. 

Cholinergic neurons. Neurons in which choline acetyltransferase synthesizes acetylcholine, accumulates it in synaptic vesicles and releases it, upon depolarization, in the quantal mode. Those neurons located in the septal/ subcortical and cortical regions of the brain are responsible for cognitive and memory functions. Cholinergic motor neurons of anterior horns of medulla oblongata form neuro-muscular synapses responsible for voluntary movements of striated muscles. 

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