The Ginkgo biloba special extract EGb 761® improves behavioral activity and cerebral blood flow in aged Beagle dogs with mild cognitive dysfunction

Aging in dogs, like in humans, is frequently accompanied by neurodegenerative processes associated with progressively increasing cognitive impairment. These disturbances are now considered to represent a discrete geriatric disorder called canine cognitive dysfunction syndrome (CCD). The main symptoms of CCD are an altered sleep-wake cycle, reduced social interaction, changes in residential behavior, disorientation, and reduced activity. Pathological changes associated with these cognitive deficits include amyloid deposits in the brain, changes in cerebral blood flow, glucose metabolism, and loss of white matter.

Previously, EGb 761® has been shown to exert beneficial effects in treating disorders associated with impaired cognitive function. Thus, it was the aim of the present study to examine the influence of EGb 761® on behavioral activity as well as cerebral and peripheral blood flow in aged (> 8.75 years) male and female Beagle dogs (N = 8) with mild cognitive dysfunction. The animals received EGb 761® at oral doses of 1.5, 3, 10 and 30 mg/kg for each 6 days with intermittent placebo phases in between. Blood flow in the middle cerebral, carotid and femoral artery was measured by ultrasound while behavioral activity was monitored with the use of the Actiwatch method. The study demonstrated a dose-related response of the cerebral vessels that lasted for at least six days. Dilation of cerebral vessels and related increase in blood flow was most pronounced at doses of 3 and 10 mg/kg. Similarly, EGb 761® caused an increase in activity that peaked at a dose of 3 mg/kg with a declining effect at higher doses. A significant effect on peripheral blood flow was not observed.

The results indicate that EGb 761^® provides a safe alternative for the treatment of dogs with CCD, which may produce cardiovascular benefits. In addition, the data support the therapeutic application of EGb 761® in the treatment of cerebral circulatory complaints as well as cognitive disorders in humans.