A study of compounds which initiate and block nerve impulses in the perfused rabbit liver.

1. A technique for the perfusion of the rabbit liver with Krebs solution is described: the hepatic nerves were monitored for centripetal action potentials. Spontaneous afferent activity, and a good response to stimulating agents persisted for 7 h or longer.2. Action potentials were elicited by injections or infusions of acetylcholine, 5-hydroxytryptamine, bradykinin, phenyldiguanide, adrenaline and various other compounds. From comparison with experiments carried out in vivo by other authors, it would appear that most of the nerves stimulated were afferent.3. Inhibition of action potentials, either those occurring spontaneously or those elicited by injections, was produced by aspirin, paracetamol, mepyramine, chlorpheniramine, procaine and lignocaine but not by morphine or atropine. Pentolinium produced some inhibition, as did hexamethonium in concentrations of about 7.5 mug/ml.4. Three methods for using the preparation for the assessment of local anaesthetic action are described.5. Lobeline, potassium cyanide and 2,4-dinitrophenol stimulated nerve bundles which were not stimulated by anoxia or hypoxia.