Pharmacological studies on feline Betz cells.

1. A study has been made of the sensitivity of single neurones in the pericruciate cortex of anaesthetized and unanaesthetized cats to cholinomimetics administered electrophoretically from multibarrel micropipettes.2. A high proportion of deep pyramidal cells, including Betz cells, were excited by these substances, and the receptors involved have muscarinic characteristics.3. Atropine specifically reduced the sensitivity of cortical neurones to acetylcholine, but no such action could be demonstrated for dihydro-beta-erythroidine, gallamine or general anaesthetics.4. The significance of these results is discussed in relation to the possible synaptic or non-synaptic action of acetylcholine upon cortical neurones.