SUMMARY1. Anoxic perfusion of the isolated rat heart releases noradrenaline in the absence of sympathetic nerve fibre stimulation.2. Anoxic noradrenaline release is enhanced by reducing the extracellular Na+ concentration, consistent with the proposal that such release occurs by carrier‐mediated efflux.3. Release is also enhanced by lignocaine but inhibited by amiloride and ethylisopropylamiloride, suggesting that sodium entry into adrenergic nerve terminals during anoxia occurs by Na+/H+ (and possibly Na+/Ca2+) exchang