Cholinergic transmission

Cholinergic Transmission is the process of synaptic transmission which uses mainly acetylcholine as a transmitter. Cholinergic transmission is found widely in the peripheral and central nervous system, where acetylcholine acts on nicotinic and muscarinic receptors. 

Cholinergic neurotransmission ChEs terminate cholinergic transmission in the central nervous system (CNS), in NMJs and in the autonomic system (the parasympathetic system, somatic motor nerves and pre-ganglionic sympathetic nerves). A few sensory cells and the NMJ in nematodes also include ChEs. 

Traumatic brain injury is the most common cause of death in subjects under the age of 40, and an important risk factor for AD. Loss of hippocampal cells and depletion of ACh and of muscarinic receptors can be attenuated in injured experimental animals, improve blood perfusion in ischemic areas and increase cholinergic transmission in cortex and hippocampus the same mechanism invoked for treatment of VD. 

Cholinergic transmission, but nerve cell chain originates in the thoracolumbar part of the spinal cord and is therefore sympathetic, alpha, a beta, 3. 

Figure 13.3. An overview of the chemical events at a cholinergic synapse and agents commonly used to alter cholinergic transmission acetyl CoA, acetyl coenzyme A Ch, choline. Nicotine and scopolamine bind to nicotinic and muscarinic receptors, respectively (nicotine is an agonist while scopolamine is an antagonist). Most anti-Alzheimer drugs inhibit the action of the enzyme cholinesterase.

The answers arc 488-d, 489-h. (Katzang, pp 108-112, 1020.) Atropine blocks muscarinic cholinergic transmission in the brain and in the autonomic nervous system. The result is dry mouth, thirst, dry and hot skin, tachycardia, urinary retention, ataxia, restlessness, excitement, and hallucinations, followed by stupor, delirium, respiratory depression, coma, and death. 

Involvement of several proteolytic enzymes, secretases, is probably crucial for this process but other hypotheses, including, for example, cholinergic transmission or accumulation of metal ions, have also been considered. Future perspectives in this area concern the search for novel pharmaceuticals that cross the blood-brain barrier, without side effects (e.g., the dyskinesias of L-Dopa), or potent and selective inhibitors of improper cleavage of amyloid protein, or even stem cell therapy to restore neuronal cells. 

Opioid effects on memory are consistent in humans and animal models (Braida et al. 1994 Saha et al. 1991). Verbal and visual memory are impaired by morphine one hour after oral administration (Hanks et al. 1995 Kerr et al. 1991). These could be due to direct neuronal effects of opioids, or perhaps through indirect effects on cholinergic transmission. However, in some animal paradigms morphine can enhance memory consolidation through indirect dopaminergic mechanisms (Castellano et al. 1994). 

Pertwee RG, Ross TM. (1991). Drugs which stimulate or facilitate central cholinergic transmission interact synergistically with delta-9-tetrahydrocannabinol to produce marked catalepsy in mice. Neuropharmacology. 30(1) 67-71. 

Acetylcholine has been implicated in learning and memory in all mammals, and the gross deficits in memory found in patients suffering from Alzheimer s disease have been ascribed to a defect in central cholinergic transmission. This transmitter has also been implicated in the altered mood states found in mania and depression, while many different classes of psychotropic drugs are known to have potent anticholinergic properties which undoubtedly have adverse consequences for brain function. 

Cefadroxi1, 440 Cefamandole, 441 Cefazolin, 442 cefoxitin, 435, 443 Cephalexin, 439 Cephamycin C, 442 Cephradine, 440 Cephapirin, 441 Cetophenicol, 46 Chioramphenicol, 28, 45 Chlordiazepoxide, 401 Chlormadinone acetate, 165 p-Chlorophenylalanine, 52 Chlorothiazide, 395 Chlorpromazine, 409 Cholinergic transmission, 71... 

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