We speculate, therefore, that the recruitment of EGF receptor-dependent signaling events that limit calcium-dependent chloride secretion allows the Salmonella infection to become established by preventing the short burst of chloride (and accompanying fluid) secretion from washing away the bacteria before they are able to invade (Figure 2). While these data do not explain why patients infected with S typhimurium experience diarrhea, they may elucidate the mechanisms for initial colonization and evasion of host defenses.
On the other hand, at later times (hours to days) after the addition of S typhimurium to epithelial cell monolayers, there is a significant increase in the rate of spontaneous chloride secretion, which might correlate with the diarrheal response in vivo.
Figure 2) Early (seconds to minutes) signaling events that occur in intestinal epithelial cells infected with Salmonella typhimurium, and their consequences. Bacteria bind to the apical membrane of polarized epithelial cells , thereby elevating cytosolic calcium, which ordinarily would activate chloride secretion. The bacterially-evoked increase in cytosolic calcium, however, simultaneously results in phosphorylation of the epidermal growth factor receptor (EGFr), perhaps via the calcium-sensitive soluble tyrosine kinase, Pyk-2, thereby leading to subsequent EGFr-related signaling events. These are then presumed to countermand the prosecretory signal that might otherwise increase chloride secretion, and we hypothesize that the inhibition of secretion is required to allow bacterial invasion . Further details are provided in the text. AP Apical; BL Basolateral You will soon see how easy it is to start the treatment if you have a reliable pharmacy offering cialis super active online for sale or any other medications you may need for the specific medical issue you may have that requires treatment.