Correlation of hydrophobic character of opioid peptides with their biological activity measured in various bioassay systems.

Relative hydrophobicity of a series of enkephalin-like peptides has been studied by partitioning in the aqueous polymeric Ficoll-dextran biphasic system. The activities of the peptides in the guinea pig ileum, mouse vas deferens and rat brain receptor binding assay systems have been examined. The biological activities of the peptides in the two latter assays were correlated with their hydrophobic character.

[Relationship between the effect of bradykinin on microvessels and their initial tonus].

The effect of bradykinin on microcirculation was studied in vivo on the rat mesentery. Bradykinin (0.01--10 micrograms) caused three types of reactions of arterioles and venules (constriction, dilatation, no changes in the diameter) in relation to the dose used.