Fluorescent histochemical localisation of quinacrine-positive neurones in the guinea-pig and rabbit atrium.

Quinacrine-fluorescent nerve fibres and nerve cell bodies are described in the right and left atria of the guinea-pig and rabbit. The nerve cells (20 to 35 micrometers in diameter) are found predominantly in the right atrium in both species. The nerve fibres are varicose and innervate both the muscle and many blood vessels. The quinacrine fluorescent neural structures are unaffected by chemical sympathectomy with 6-hydroxydopamine. The distribution of quinacrine-positive nerve fibres and cell bodies are compared to the distribution of adrenergic and acetylcholinesterase-positive nerves in the atrium of both species. Quinacrine fluorescence appears to be selective for non-adrenergic, non-cholinergic nerves and the possibility that it is binding to high contents of ATP discussed.