Everted Portal Vein

Abstract

Three preparations of the rat hepatic portal vein, everted, noneverted and longitudinal strip, were examined for their responsiveness to noradrenaline [norepinephrine] (NA), substance P (SP) and eledoisin (ED). The longitudinal strips and the everted veins exhibited similar sensitivities to these compounds, whereas the noneverted vein was 2-4 times less sensitive. The time course to generation of a maximal response was markedly slower for the noneverted vein. The poor reactivity of the noneverted vein is attributed to a reduced accessibility of the compounds to receptor sites. The myogenic responses of the longitudinal strips to NA and ED but not SP were characterized by a tonic-type contracture, whereas everted and noneverted preparations responded to the peptides, at low and intermediate concentrations, with large-amplitude and long-duration contractions. The everted vein is presented as a useful preparation for evaluation of drug-receptor interactions.