Neuroprotective effects of the dopamine agonists pramipexole and bromocriptine in 3-acetylpyridine-treated rats.

The neuroprotective effects of pramipexole, a dopamine agonist, were investigated in 3-acetylpyridine (3-AP)-treated Wistar rats. Bromocriptine was used as a reference compound to compare the results obtained with pramipexole. A significant reduction (P < 0.01) in cerebellar cGMP and ATP was observed 96 h after treatment with 3-AP (500 micromol/kg, i.p.). Both pramipexole and bromocriptine significantly attenuated 3-AP-induced reduction in cerebellar cGMP and ATP. Consistent with the neurochemical effect, both pramipexole and bromocriptine prevented 3-AP-induced loss of motor coordination. 3-Acetylpyridine produced a significant (P < 0.01) loss of neurons in the inferior olivary nucleus. Treatment with pramipexole and bromocriptine partially, but significantly (P < 0.01), prevented the loss of inferior olivary neurons. There was no reduction in the temperature of the animals, indicating that hypothermia was not responsible for neuroprotection.