Effect of enflurane on cerebellar cGMP and on motor activity in the mouse.

The effect of enflurane on the cerebellar content of the intracellular mediator cyclic 3', 5'-guanosine monophosphate (cGMP) and on motor activity was studied in mice. Seizures, as an index of increased motor activity, associated with an increase in cerebellar cGMP content were induced with isoniazide or picrotoxin. Enflurane 0.28-1.68 vol% produced a dose-dependent, reversible decrease in cerebellar cGMP (by about 50% at 0.28 vol%) and delayed or prevented both the increase in cerebellar cGMP and the convulsions induced by isoniazide. Enflurane also protected against picrotoxin-induced convulsions, but not against strychnine-induced convulsions which presumably do not involve cerebellar mechanisms. These results indicate that enflurane affects the cerebellar mechanisms controlling motor activity and it is postulated that this action contributes to the decrease in muscle tone induced by enflurane.