Cimetidine is a histamine congener which inhibits the binding of histamine competitively to H2 receptors. After its binding to the H2 receptor, cimetidine causes a range of pharmacological responses through the inhibition of secretion of gastric acid by parietal cells as well as gastrin and pepsin output. Cimetidine also acts to block cytochrome P-450 activity and it may therefore be used in future as a neoadjuvant therapy.
Cimetidine reduces the nocturnal and basal secretion of gastric acid and also reduces acidity, gastric volume as well as the amount of released acid upon particular stimuli such as caffeine, food, betazole, insulin and pentagastrin. The structure of cimetidine (Fig 1. 3) permits it to competitively bind to the H2 receptors, the target for histamine. Cimetidine is used in the management of duodenal and gastric ulcers, pathological hepersecretory and gastroesophageol reflux conditions.
The inhibition of cytochrome P-450 has raised increased attention as it interferes with the metabolism of drugs and other xenobiotics. Fig 1. 3 Structure of Cimetidine Fig 1. 3 The structure of cimetidine gives it the competitive ability to bind to H2 receptors just like histamine [8] Conclusion The studies of receptor-ligand interactions have been critical in areas of pharmaceutical research.
The analysis of physical properties of compounds has moved a whole new level where computer-assisted designs can be made and extrapolated to the real-life situation. Molecules can be interacted with a number of receptors using computer software to come up with conclusive report. This approach of drug discovery is fast and does not face ethical issues surrounding the animal and human experiments.
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