This rat strain is used as an animal model of depression co-morbid with anxiety (as opposed to the Flinders pure depression model) and demonstrates hormonal, behavioral and physiological phenotypes resembling those found in depressed patients. The animals demonstrate increased immobility in the forced swim test, decreased activity in the open field and reduced responsiveness to antidepressants.

Reproduced with permission from Elsevier
(http://www.sciencedirect.com/science/journal/03064530)

Rittenhause et al, 2002: Immobility behavior during a swimming session (FST) in Wistar Kyoto rats (black bars) compared to Sprague Dawley rats (white bars). WK rats are considerably more immobile than Sprague Dawley rats at time points of 5, 10 and 15 (end) minutes of 15 min duration swim sessions.  Data displayed with standard errors

References:

Will CC, Aird F, Redei EE (2003) Selectively bred wistar-kyoto rats: an animal model of depression and hyper-responsiveness to antidepressants. Mol Psychiatry 8(11):925-932

Rittenhouse PA, Lopez-Rubalcava C, Stanwood GD, Lucki I (2002) amplified behavioral and endocrine responses to forced swim stress in the wistar-kyoto rat. Psychoneuroendocrinology 27(3):303-318