Changes in extracellular levels of dopamine metabolites in somatosensory cortex after peripheral denervation.
This study examined the effects of a nerve transection on monoamine release from primary somatosensory cortex. The technique of microdialysis was employed to sample extracellular levels of norepinephrine (NE), 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindole-3-acetic acid (5-HIAA) and homovanillic acid (HVA) in the barrel field of freely moving rats following the surgical transection of the contralateral infraorbital nerve. Microdialysates obtained 3, 4, and 5 days after deafferentation were analyzed using high-performance liquid chromatography with electrochemical detection. We found a significant increase in the release of the dopamine metabolites, DOPAC and HVA from the deafferented cortex. Three days after deafferentation the release of DOPAC was three-fold higher in the deafferented than in the control animals, and remained about 100% higher in the next two days in this group of animals. The release of HVA showed a gradual increase following the deafferentation procedure, since a 92% larger value on day 3 increased to a 338% difference on day 5. On the other hand, the release rate of NE and the levels of the serotonin metabolite 5-HIAA were not significantly affected by the deafferentation procedure. These results are discussed in the context of the possible participation of dopamine in the reorganization of the deafferented somatosensory cortex.
Jiménez-Capdeville
M E
ME
Departmento de Bioquimica, Facultad de Medicina, Universidad Autonoma de San Luis Potosi, Mexico.
Reader
T A
TA
Molina-Holgado
E
E
Dykes
R W
RW
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D003714:Denervation; D004298:Dopamine / Q000378:metabolism*; D006719:Homovanillic Acid / Q000378:metabolism; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D009473:Neuronal Plasticity / Q000502:physiology*; D009638:Norepinephrine / Q000378:metabolism; D010525:Peripheral Nerves / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000378:metabolism*
D015306:Biogenic Monoamines; D015102:3,4-Dihydroxyphenylacetic Acid; D006897:Hydroxyindoleacetic Acid; D004298:Dopamine; D009638:Norepinephrine; D006719:Homovanillic Acid