Rabbit vas deferens: A specific bioassay for opioid κ-receptor agonists

Differential sensitivity of models of antinociception in the rat, mouse and guinea‐pig to μ‐and κ‐opioid receptor agonists

“…The degree of efficacy was defined as follows: high efficacy K-agonists are able to inhibit completely the twitch of the field-stimulated rabbit vas deferens preparation (Oka et al, 1981) and cause a maximal diuretic effect in the rat, medium efficacy K-agonists partially inhibit the twitch of the rabbit vas deferens but still cause maximal diuresis, and low efficacy K-agonists do not inhibit the twitch of the rabbit vas deferens and produce low maximum diuresis. High efficacy p-agonists inhibit completely the twitch of the fieldstimulated rat vas deferens preparation (Smith & Rance, 1983) and cause maximal respiratory depressant and constipating effects in the rat in vivo (Hayes & Tyers, 1983), medium efficacy gu-agonists partially inhibit the twitch of the rat vas deferens but still cause maximal respiratory depression and constipation, and low efficacy i-agonists do not inhibit the twitch of the rat vas deferens and produce low maximum res-piratory depression and constipation.…”

Selectivities of opioid peptide analogues as agonists and antagonists at the δ‐receptor

“…Therefore, the ratio of the IC50 value in mouse vas deferens to the IC50 value in guinea-pig ileum is an indication of the selectivity of the peptide for the (Oka et al, 1981;1982;Corbett et al, 1982).…”

Central and peripheral actions of the novel κ‐opioid receptor agonist, EMD 60400

“…Rabbit vas deferens This assay was performed in a manner similar to that of Oka et al (1980). Briefly, vasa deferentia were isolated from New Zealand white rabbits (ca.…”