Affiliations: Department of Neuroscience and Neurology, University
of Kuopio, Kuopio, Finland | A.L Virtanen Institute, University of Kuopio, Kuopio,
Finland | Department of Neurology, University Hospital of Kuopio
and Brain Research and Rehabilitation Center Neuron, Kuopio, Finland
Note: [] Corresponding author: Jukka Jolkkonen, PhD, Department of
Neuroscience and Neurology, University of Kuopio, P0 Box 1627, 70211, Kuopio,
Finland. Tel.: +358 17 162519; Fax. +358 17 162M; E-mail:
[email protected]
Abstract: Purpose: Tbc present study compared tbc effect of chronic
administration of the selective cc2-adrenoceptor antagonist, atipamezole, on
performance in behavioral tests that differ in motoric complexity in two
experimental stroke models. Methods: Transient occlusion (120 min) of the
middle cerebral artery (MCA) using the intraluminal method was used to produce
corticostriatal infarcts and permanent occlusion of distal MCA by
electrocoagulation was used to produce cortical infarcts. Chronic atipamezole
treatment (1 rng/kg, s.c., once per day) was started 2 days after ischemia
induction and continued until the end of the experiment, 35 days after ischemia
induction. Behavioral performance of the operated rats was assessed 30 min
after drug administration using the limb-placing test and Montoya's staircase
test. Results: Atipamezole facilitated spontaneous recovery in the limb-placing
task particularly in rats subjected to transient MCA occlusion. The analysis of
retrieved pellets in Montoya's staircase test suggests that there is no
recovery (Time effect, P > 0.05) in the use of the impaired forelimb
(contralateral-to-lesion) following transient MCA occlusion, whereas there was
some recovery following permanent MCA occlusion (Time effect, P < 0.001).
The impairment was bilateral in rats subjected to transient MCA occlusion.
Atipamezole treatment did not affect the use of the impaired forelimb to
retrieve pellets following transient MCA occlusion, but there was a tendency to
facilitate impaired forelimb use following permanent MCA occlusion
(Time*Treatment interaction, P = 0.086). Conclusion: Transient occlusion of the
MCA produced a severe, long lasting, and bilateral deficit in skilled forelimb
use. Permanent occlusion of the distal MCA was associated with less severe
impairment, which was alleviated to some extent by administration of
atipamezole. This is in contrast to spontaneous recovery and recovery-enhancing
effects of atipamezole in the limb-placing test, particularly in the transient
MCA occlusion model.
