Selective inhibition by glycine of some somatic reflexes in the cat

1. The effects of intracerebroventricular or intrathecal administration of glycine on some somatic reflexes in chloralosed cats were investigated.2. Glycine produced marked inhibition of the flexor reflex (FR) and crossed extensor reflex (CER) at low doses (2.5-5.0 mg) but even large doses (up to 40.0 mg) had no effect on the facilitation or inhibition of the patellar reflex produced by stimulation of either the reticular formation or the sciatic nerve. The linguomandibular reflex (LMR) could be blocked by 10-20 mg glycine.3. Glycine antagonized strychnine-induced facilitation of FR, CER and LMR and was 5-6 times as active as gamma-aminobutyric acid in this respect.4. The possibility of glycine being a transmitter in spinal pathways is discussed.