Priming with L-DOPA differently affects dynorphin and substance P mRNA levels in the striatum of 6-hydroxydopamine-lesioned rats after challenge with dopamine D1-receptor agonist
In unilaterally 6-hydroxydopamine-lesioned rats, potentiation of D1-agonist-induced turning behavior by priming with L-DOPA was correlated with changes in striatal neuropeptide mRNA levels. In non-primed rats, administration of the D1-agonist SKF-38393 markedly increased dynorphin and substance P mRNA levels in the lesioned striatum. Priming with L-DOPA dissociated the response of the two neuropeptides to the D1-agonist, with higher dynorphin and reduced substance P mRNA levels. (C) 1998 Elsevier Science B.V. All rights reserved.