PERSISTENT INCREASES IN DOPAMINE D-2 RECEPTOR MESSENGER-RNA EXPRESSION IN BASAL GANGLIA FOLLOWING KINDLING

Amygdala kindling resulted in significant increases in the expression of D-2 receptor mRNA in the nucleus accumbens and striatum 30 days fol lowing the last kindling stimulation. Densitometric analyses of tissue sections incubated in the presence of an oligonucleotide probe direct ed against D-2 receptor cDNA indicated a 20-35% increase in D-2 recept or mRNA in these regions following kindling. Kindling from the amygdal a followed by piriform cortical kindling in the transfer paradigm (ove rkindling) resulted in significant further increases in D-2 receptor m RNA expression in both the accumbens (150% increase) and striatum (120 % increase). There were no observed hemispheric asymmetries in D-2 rec eptor mRNA in either kindled or overkindled animals. The data indicate an enduring upregulation of extrapyramidal D-2 receptor mRNA followin g the kindling process. How this change may relate to kindling-induced alterations in seizure susceptibility or behaviors mediated by limbic dopaminergic pathways are questions for future studies.