Abstract

1 A new technique for determining venous compliance at a standardized congestion pressure has been developed based on the optical method described by Nachev, Collier & Robinson (1971). It uses a linear variable differential transformer for a direct and continuous recording of venous compliance. 2 This method has been used to establish dose-response curves for the constrictor effects of noradrenaline, adrenaline, 5-hydroxytryptamine and dihydroergotamine after direct local infusion. 3 A parallel shift to the right of the noradrenaline dose-response curves was observed after local infusion of phentolamine, showing that the method can be used also to study interactions between agonists and antagonists on human veins in vivo. The usefulness of this technique for investigating the effects of orally administered drugs has also been established. The venoconstrictor action of dihydroergotamine reached its maximum after 1.5 h and remained almost constant for the period of observation (8 h).

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