Affiliations: IRCCS S.Lucia, Via Ardeatina 304, 00179 Rome,
Italy | Department of Psychology, University of Rome "La
Sapienza", Rome, Italy | University of Naples "Parthenope", Naples,
Italy
Note: [] Corresponding author: Laura Petrosini, Dept. of Psychology,
University of Rome "La Sapienza", Via dei Marsi 78, 00185 Rome, Italy.
Tel./Fax: +39 06 49917522; E-mail: [email protected]
Abstract: Purpose: To test whether activation of NMDA receptors is required
for the maintenance of the posture and motor behavior recovered from cerebellar
lesions, an NMDA antagonist (CGS 19755) was systemically administered to
totally or partially cerebellectomized rats. Methods: Three groups of animals were tested: rats that had
undergone a total cerebellectomy four months before drug administration; rats
that had undergone a right hemicerebellectomy four months before drug
administration; intact control animals. Results: Under drug action in the control animals the postural
pattern was slightly influenced, showing a light worsening, and motor skills
requiring coordinated motor performance and subtle balance control were
markedly worsened. Conversely, in the lesioned groups the cerebellar
symptomatology dramatically worsened, and both groups of animals looked like
they had just been operated, exhibiting the whole repertoire of postural and
motor behaviors of cerebellar origin. In particular, limb hyperflexion,
wide-based locomotion and the tendency to side falls were prevalent in the
cerebellectomized animals, while tremor and body tilt were prevalent in the
hemicerebellectomized group. Conclusion: The reappearance of severe postural and motor
symptomatology has to be interpreted as a "decompensation" evoked by the
NMDA-receptor antagonist, suggesting the involvement of NMDA receptors in the
maintenance of compensation of disturbances of cerebellar origin.
Keywords: Cerebellar compensation, neural plasticity, motor behavior, posture, glutamate receptors, rat
