The effect of @entity1808 upon electrogenic ion transport in XXXX intestinal epithelia.

@entity5230 @entity1022 @entity1808 @entity1483 @entity3352 @entity3897 @entity2865 @entity35 @entity9974 @entity1813 @entity17295 @entity45506
Epithelial sheets from @entity35 jejunum and descending colon have been shown to respond to @entity1808 (AII) when studied under short-circuit conditions and bathed on both sides with Krebs-Henseleit solution. The octapeptide AII elicited increases in short-circuit current (SCC) in preparations of jejunum and decreases in SCC in the descending colon; both responses occurred when the peptide was applied to the basolateral surface, but not when applied to the apical solution. Responses in both tissues were highly specific, being inhibited by a range of AII antagonists with the following order of potency: [Sar1. Thr8]-AII greater than [Sar1. Leu8]-AII greater than [Sar1. Ile8]-AII greater than [Sar1. Ala8]-AII greater than [Des,Asp1. Ile8]-AII in @entity35 jejunum. AII responses were not affected by alpha- or beta- adrenoceptor antagonists, @entity3897 or @entity1022 . AII responses were totally inhibited by the @entity2865 channel blocker, @entity45506 ( @entity9974 ) while cotransport inhibitors e.g. @entity17295 and @entity1483 significantly reduced the size of AII responses in colon and jejunum. These patterns of activity suggest that in the jejunum the responses result from electrogenic @entity2865 secretion. Although AII responses in colon were sensitive to DPC the transporting ions have not yet been identified. Both @entity5230 and @entity3352 inhibited the increase in SCC elicited by AII in the jejunum, and the reduction in SCC caused by AII in the colon. Taken together these results indicate that @entity1813 are involved in AII responses in both tissues. This is the first study to demonstrate a direct, electrogenic effect for AII on transporting epithelia from the gastrointestinal tract. The responses are most probably initiated by All interacting with previously identified specific All receptors within the epithelial membranes.
