An examination of glutamate decarboxylase(65) immunoreactive puncta with respect to rat ventral pallidum neurons after repeated cocaine administration.
The ventral pallidum is known to have topographically organized reciprocal gamma-aminobutyric acid-ergic projections with the nucleus accumbens, and changes in these connections may play a role in mediating the behavioral sensitizing effect of repeated exposure to cocaine. The present study investigated glutamate decarboxylase-65 (GAD(65)) immunoreactivity in the rat ventral pallidum after repeated cocaine administration. Male Sprague-Dawley rats were administered bi-daily injections of 15 mg/kg cocaine or saline vehicle for 5 consecutive days. After 2 or 14 days of withdrawal, ventral pallidal sections were immunocytochemically processed for GAD(65) immunoreactive puncta and counts were made. In both groups, there were no statistically significant differences in the number or density of GAD(65) puncta in medial or lateral portions either in contact with neuronal cell bodies or in the neuropil after 2 or 14 days of withdrawal. The results suggest that there is no alteration in the number of GABAergic boutons expressing GAD(65) immunoreactivity in the ventral pallidum after repeated exposure to cocaine.
De Leon
K R
KR
Department of Psychology, Northeastern University, 360 Huntington Avenue (125 NI), Boston, USA. kdeleon@lynx.dac.neu.edu
Todtenkopf
M S
MS
Stellar
J R
JR
D000818:Animals; D003042:Cocaine / Q000009:adverse effects*; D018765:Dopamine Uptake Inhibitors / Q000009:adverse effects*; D004334:Drug Administration Schedule; D005917:Globus Pallidus / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D005968:Glutamate Decarboxylase / Q000378:metabolism*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D009714:Nucleus Accumbens / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D017729:Presynaptic Terminals / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D018765:Dopamine Uptake Inhibitors; D007527:Isoenzymes; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2; D003042:Cocaine