Ketamine suppression of chemically induced convulsions in the two-day-old white leghorn cockerel.

Ketamine has been evaluated for convulsant properties in animals and humans with contradictory results. The present investigation evaluated the convulsant properties of ketamine in a previously unreported animal model. Two-day-old chicks were selected as test animals because they have incomplete blood-brain barriers and thus greater penetrance of xenobiotics affecting the central nervous system. Control and experimental animals were given a central nervous system stimulant, pentylenetetrazol (Medtrazol) at a dosage level (100 mg/kg) causing convulsions in 90% of animals. The effect of ketamine pretreatment was then observed for the: (1) number of animals convulsing; (2) time of onset of convulsions; and (3) mortality. Ketamine (100 mg/kg) significantly decreased the number of animals that convulsed and decreased mortality; 10 mg/kg of ketamine significantly prolonged the time of onset of convulsions. This study does not support the conclusion that ketamine is a convulsant. Ketamine has significant anticonvulsant properties in the young chick model.