Serotonergic involvement in the backward tumbling response of the parlor tumbler pigeon

The parlor tumbler is a breed of domestic pigeon which displays a hereditary movement disorder resulting in backward somersaulting upon attempting to fly. A neurochemical abnormality has been suggested to underlie this behavior. The effect on tumbling of several drugs with serotonergic actions was studied. Increasing available serotonin with 5-hydroxytryptamine (50 mg/kg) plus fluoxetine (10 mg/kg) as well as using amitriptyline (10-20 mg/kg) significantly suppressed tumbling without sedation. This suggests that serotonin mechanisms may be involved in the tumbling response.