Fig. 1.
Effects of enhanced monoaminergic transmission on dystonia induced by cerebellar microinjection of kainate. (A) Peripheral administration of amphetamine, which nonselectively increases the extracellular concentrations of the monoamines dopamine, norepinephrine, and serotonin, dose-dependently reduced the severity of dystonia induced by microinjection of kainate to the cerebellum (one-way ANOVA; F3,28 = 4.813, P < 0.01, n = 8/dose). (B) The selective norepinephrine reuptake inhibitor nisoxetine did not affect the disability score (one-way ANOVA; F3,27 = 0.468, NS, n = 7 to 8/dose). (C) Citalopram, a selective serotonin reuptake inhibitor, did not affect the disability score (one-way ANOVA; F3,26 = 0.317, NS, n = 7 to 8/dose). (D) The selective dopamine reuptake inhibitor GBR-12909 dose-dependently reduced the severity of dystonia (one-way ANOVA; F3,28 = 3.853, P < 0.05, n = 8/dose). Disability scores lower than 10 (dashed lines) suggest abnormal motor behavior, such as an unsteady gait, but not overt dystonia. Values represent the mean of the cumulative disability score in 1 hour ± S.E.M. *P < 0.05; **P < 0.01 compared with vehicle, Holm-Sidak multiple comparisons test. NS, not statistically significant.