Cholinergic nerve fibres

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... 

Chole- Relating to the biliary system, cholestasis The failure of the normal bile flow to the intestine, causing cholestatic jaundice, cholinergic Nerve fibres that release ACETYLCHOLINE, cholinesterases Enzymes that hydrolyse choline esters, especially ACETYLCHOLINE of which there are two main forms acetylcholinesterase ( true cholinesterase ) is specific for acetylcholine, rapid in this action, and has a discrete distribution being especially located near cholinergic nerve terminals (and in erythrocytes) butyrylcholinesterase ( pseudo cholinesterase) is less selective and is able to hydrolyse some drugs (e.g. SUCCINYLCHOLINE CHLORIDE). Many drugs are known that inhibit the action of these enzymes. See anticholinesterases. chromatin A protein found in the nucleus which stains with basic dyes. It is used in the study of the behaviour of... 

A very substantial contribution to the identification of the cholinergic nerve elements in the hippocampal region was the demonstration by Shute and Lewis (1961) and Lewis and Shute (1967) that AChE disappears from the neuropil of this region after transection of the fimbria (Fig. 5). Corresponding results were obtained for ChAc (Lewis et al., 1967). The few perikarya that stained for AChE, retained their staining after the transection. AChE and ChAc accumulated in fibres in fimbria... 

Evidence that acetylcholine is a chemical mediator of synaptic transmission elsewhere in the central nervous system is circumstantial but convincing. Acetylcholine is the transmitter substance from motor nerves, preganglionic autonomic fibres and the postganglionic fibres of the parasympathetic system to their respective effector cells. In all these fibres, the activity of choline acetyltransferase (choline acetylase), the enzyme responsible for the synthesis of acetylcholine, is high. Conversely, its activity is negligibly low in sensory nerve fibres and transmission from these fibres is demonstrably non-cholinergic in nature . It is reasonable, therefore, to... 

A study of the distribution, in the mammalian central nervous system, of the various substances discussed in this review reveals that none—except y-aminobutyric acid which has general metabolic as well as humoral functions—is as widespread as acetylcholine and there is no general tendency for fibres deficient in acetylcholine to contain correspondingly large amounts of any of the other substances. This is an important point, since the non-cholinergic excitatory transmitter should be found in at least a number of acetylcholine-free nerve tracts. Instead, it appears that some areas of the nervous system contain a multiplicity of humoral substances while others have none at all. 

Hefti, F., Hartikka, J., Eckenstein, F., Gnahn, H., Heumann, R. and Schwab, M. (1985) Nerve growth factor increases choline acetyltransferase but not survival or fibre outgrowth of cultured fetal septal cholinergic neurons. Neuroscience 14 55-68. 

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