THE EFFECT OF HISTAMINE ON ION-TRANSPORT IN PORCINE JEJUNUM

Histamine is present in the gastrointestinal tract, and is an importan t mediator in gastrointestinal type I hypersensitivity reactions. The effect of histamine on ion transport in ''stripped'' porcine jejunal p reparations was investigated. Histamine caused a transient increase in short-circuit current (SCC), which seemed to be concentration depende nt. A maximum response was obtained at 0.1 mM. The histamine response was attenuated (44.8%) by the neuronal conduction blocker, tetrodotoxi n (TTX), indicating that enteric neurotransmitters are involved. The n eurokinin-l antagonist, CP 99,994, did not alter the response to hista mine (0.1 mM). Thus, tachykinins acting at NK-1 receptors do not seem to be involved in the histamine response. (C) 1997 Elsevier Science In c.