Concentration of amino acid neurotransmitters in the somatosensory cortex of the rat after surgical or functional deafferentation.
Hindlimb unloading is considered as a model of functional deafferentation, since in this situation the tactile information from the paw and the proprioceptive input from the limb are dramatically reduced. Unloading induces a shrinkage of the cortical representation of the affected body part associated to a reorganization of topographic maps and to an expansion of receptive fields. Previous studies have suggested that cortical plasticity was the result of a change in the balance of excitation and inhibition in the cortex. The aim of the present study was thus to determine whether deafferentation of the hindlimb representation in the somatosensory cortex, by 14 days of unloading or by surgical means (selective dorsal rhizotomy during 17 days), can change the concentration in various amino acid neurotransmitters in the deprived cortex. The present findings indicate that both types of deafferentation result in a decrease in inhibitory amino acids (GABA, taurine) without significant changes in the main excitatory amino acid (glutamate). In conclusion, the present results support the idea that cortical changes are more likely due to a release from inhibition than to an increased excitation.
Canu
Marie-Hélène
MH
Unité de Neurosciences et Physiologie Adaptative, Groupe Plasticité Neuromusculaire, Université des Sciences et Technologies de Lille, 59655, Villeneuve d'Ascq Cedex, France. canu@univ-lille1.fr
Treffort
Nicolas
N
Picquet
Florence
F
Dubreucq
Guy
G
Guerardel
Yann
Y
Falempin
Maurice
M
D000344:Afferent Pathways / Q000502:physiology* / Q000601:surgery; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D018846:Excitatory Amino Acids / Q000378:metabolism; D006614:Hindlimb / Q000294:innervation; D008297:Male; D018377:Neurotransmitter Agents / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D019051:Rhizotomy; D013003:Somatosensory Cortex / Q000378:metabolism*; D013654:Taurine / Q000378:metabolism; D016474:Weight-Bearing; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D000596:Amino Acids; D018846:Excitatory Amino Acids; D018377:Neurotransmitter Agents; D013654:Taurine; D005680:gamma-Aminobutyric Acid