EVIDENCE THAT ADRENERGIC NERVES ARE RESPONSIBLE FOR THE ACTIVE UPTAKE OF NORADRENALINE IN THE GUINEA‐PIG ISOLATED TRACHEA

6‐Hydroxydopamine (50 mg/kg, i.p.) was given to guinea‐pigs to destroy the adrenergic nerve terminals in the trachea. The destruction was demonstrated by fluorescence histochemistry, which showed a marked loss of beaded fluorescent terminal fibres and by electrical transmural stimulation of the isolated atropinized trachea, which showed a marked reduction of dilator responses. Such tracheae showed greatly reduced uptake‐with‐retention of (—)‐[ H]‐noradrenaline in incubation experiments and the efflux curve of radioactive material showed a selective but incomplete reduction in the volume of the slowly exchanging compartment. It is concluded that much, but perhaps not all, of the uptake‐with‐retention occurs into adrenergic nerves. 1975 British Pharmacological Societ