The Interrelationship between Bradykinin and Cyclo-Oxygenase Products in the Rat Small Intestine

Abstract

The effect of bradykinin on the release of prostaglandins
from the rat isolated terminal ileum has been
investigated. The release of prostaglandins from the ileum,
into the surrounding bathing fluid, was measured by
radioimmunoassay and by bioassay. Under basal conditions
more PGE-like than PGF-like material was released from the
ileum. When the ileum was incubated with bradykinin, an
increase in the release of PGF-like, but not PGE-like
material was observed.
The release of prostaglandin-like material from the
rat isolated perfused terminal ileum was assayed on the rat
fundus strip. Bradykinin perfused over either surface of
the ileum contracted the rat fundus strip more than when
the ileum was absent. No increase was observed in the
presence of indomethacin. However, it was found difficult
to quantify the release of prostaglandin-like material after
exposure to bradykinin, since contractions of the assay
tissue to bradykinin appeared to be potentiated by the
release of prostaglandin-like material from the ileum.
The effect of the cyclo-oxygenase inhibitor
indomethacin, was investigated upon contractions of the rat
isolated perfused ileum to bradykinin. Contractions of the
ileal longitudinal muscle to bradykinin during mucosal, but
not serosal perfusion of the ileum, were reduced in the
presence of indomethacin. Furthermore, in the ileum from
rats pretreated with indomethacin, contractions to
bradykinin were also only reduced during mucosal perfusion.
A similar interrelationship on the mucosal surface, between
bradykinin and cyclo-oxygenase products, was demonstrated in
the relaxation of the rat isolated perfused duodenum to
bradykinin. The additional involvement of cyclic nucleotides
and a neuronal mechanism in the response of the mucosal
perfused rat small intestine to bradykinin is suggested.
It is concluded that cyclo-oxygenase products are
involved in the response of the mucosal, but not the serosal
perfused rat small intestine to bradykinin, although the
exact nature of this involvement is unclear.

Date of Award	1979
Original language	English
Awarding Institution	Aston University