Pharmacology
Mechanism of action
Rabeprazoles mechanism of action first involves getting absorbed into the parietal cells of the stomach, which are the cells that are responsible for secreting hydrochloric acid (HCl). At this point, rabeprazole is inactive. However, rabeprazole is then secreted into the secretory canaliculus of the parietal cells, which is the space from which acid secretion occurs. Here, acid secretion is mediated by the energy-dependent acid pumps, called hydrogen potassium adenosine triphosphatase (H+/K+ ATPase) pumps. These enzymatic pumps have cysteine amino acid residues. After being activated by gastric (stomach) acid to a reactive sulfenamide intermediate, rabeprazole permanently binds the cysteine residues, forming covalent, disulfide bonds. This action fundamentally alters the configuration of the acid pump, thereby inhibiting its activity. Thus, acid can no longer be secreted into the gastric lumen (the empty space of the stomach), and the pH of the stomach increases (decrease in the concentration of hydrogen ions, H+). Due to the permanent inhibition of the individual proton pump that each molecule of rabeprazole has bound to, acid secretion is effectively suppressed until new proton pumps are produced by the parietal cells.Rabeprazole, like other medications in the same class, cannot inhibit the H+/K+ ATPase pumps found in lysosomes, a cellular organelle that degrades biological molecules, because the pumps found in these organelles lack the cysteine residues involved in rabeprazoles mechanism of action.A unique feature of rabeprazoles mechanism of action in inhibiting acid secretion involves its activation.
Amédée Galzin (1 May 1853, Parrinet, Aveyron – 14 February 1925, Parrinet) was a French veterinarian and mycologist. In 1878 he obtained his degree from the veterinary college in Toulouse. From 1879 to 1905, he served as a military veterinarian, becoming a knight of the Legion of Honour in 1899.With Abbé Hubert Bourdot, he was co-author of a series of publications (11 parts, 1909 to 1925) involving Hymenomycetes native to France; all parts being published in the Bulletin de la Société Mycologique de France. With Bourdot, he also wrote Heterobasidiae nondum descriptae (Descriptions of a few jelly fungi).With Bourdot, he was the taxonomic authority of the fungi genus Oxyporus, as well as of numerous mycological species. == References ==