Studies of depression-related states in animal models of Parkinsonism

The diagnosis of Parkinson's disease (PD) is solely based on movement disorders, but several non-motor deficits are common in PD. Depression often precedes the movement dysfunctions and continues to be a major concern during all stages of the disease. The pathophysiology of parkinsonian depression is largely unknown, but appears to partly differ from depression in patients without PD. Because of the increased awareness of the negative impact of depression on the quality of life of PD patients, there is a growing interest in developing animal models of parkinsonism that also recapitulate the depressive-like symptomatology. This review introduces paradigms for measurement of depression-like behaviors in rodents and summarizes data on behavioral, neurochemical and pharmacological changes in experimental PD models with relevance for depression-related states.