Pharmacological properties of cat's collicular auditory neurons.

Effects of various drugs on the collicular auditory neurons were examined by means of pressure microinjection and microelectrophoresis methods. 1 . Acetylcholine had stimulating action on 67 % of the nuerons tested. Most of them showed a relatively fast onset and a slow recovery. 2. Monosodium-L-glutamate excited 85 % of the neurons tested. The action was exerted with a relatively fast time course and by smaller doses than those required for acetylcholine. 3. L-aspartic acid also had an excitatory action. It was clearly much weaker than L-glutamate. 4. Eserine sulphate stimulated 60 % of the neurons tested.