Noradrenaline and tyramine action on isolated atrial muscle of endotoxin‐treated guinea‐pigs

Abstract

1 Isolated left-atrial strips of guinea-pigs were driven electrically at a constant rate and log-concentration curves were determined for the positive inotropic effect of noradrenaline and tyramine. 2 The atrial tissue from endotoxin-treated animals had a reduced sensitivity to noradrenaline and tyramine. 3 After endotoxin, the sensitizing effect of cocaine on the response to noradrenaline was normal but accumulation of ³H-noradrenaline in nerve terminals was markedly reduced. 4 Atrial tissue of endotoxin-treated guinea-pigs responded normally to stretch.