The contractile response of isolated lingual arteries from rabbits treated with bacterial lipopolysaccharide via the stimulation of B1-receptors for kinins.

要旨

The effect of intravenous injection of 10 micrograms of a lipopolysaccharide (endotoxin) extracted from E. coli to rabbits on the responses of isolated lingual arteries to des-Arg9-bradykinin (a specific kinins B1-receptor agonist) was studied. Endotoxin injection led to the appearance of the endothelium-independent contractile effect of des-Arg9-bradykinin in the arteries; endotoxin elicited this response when administered at 1, 5 or 20 hr before the experiment, in a time-interval dependent manner. The contractile response to des-Arg9-bradykinin of the arteries isolated from animals receiving endotoxin 20 hr before the experiment was attenuated by des-Arg9-[Leu8]-bradykinin (a specific inhibitor of kinins B1-receptor) or pretreatment of the animals with an inhibitor of protein synthesis (cycloheximide and actinomycin D). When compared with the effect of des-Arg9-bradykinin, bradykinin (a potent kinin B2-receptor, but weak B1-receptor stimulant) caused slight contraction of the arteries; however, this effect was not endotoxin-dependent and was not modified by des-Arg9-[Leu8]-bradykinin. Effect of in vitro preincubation with endotoxin of the arteries isolated from animals receiving saline 20 hr before the experiment was further studied. The preincubation (for 1 and 5 hr) with endotoxin of the arteries in the presence or absence of plasma had no effect on the sensitivity of the arteries to des-Arg9-bradykinin; the sensitivity was also unaffected in the presence or absence of endotoxin, thus suggesting that there is no interaction between endotoxin and some plasma-related factors with the appearance of the contraction in response to the kinin B1-receptor agonist in the arteries in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

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