title: Repeated administration of piribedil induces less dyskinesia than L-dopa in MPTP-treated common marmosets: a behavioural and biochemical investigation.
abstract: Piribedil ([1-(3,4-methylenedioxybenzyl)-4-(2-pyrimidinyl)piperazine]; S 4200) is a dopamine agonist with equal affinity for D(2)/D(3) dopamine receptors effective in treating Parkinson's disease as monotherapy or as an adjunct to levodopa (L-dopa). However, its ability to prime basal ganglia for the appearance of dyskinesia is unknown. We now report on the ability of repeated administration of piribedil to induce dyskinesia in drug naïve 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) -lesioned common marmosets compared with L-dopa and its actions on the direct and indirect striatal outflow pathways. Administration of piribedil (4.0-5.0 mg/kg orally) or L-dopa (12.5 mg/kg orally plus carbidopa 12.5 mg/kg orally twice daily) produced equivalent increases in locomotor activity and reversal of motor deficits over a 28-day study period. Administration of L-dopa resulted in the progressive development of marked dyskinesia over the period of study. In contrast, administration of piribedil produced a significantly lower degree and intensity of dyskinesia. Surprisingly, piribedil caused an increase in vigilance and alertness compared to L-dopa, which may relate to the recently discovered alpha(2)-noradrenergic antagonist properties of piribedil. The behavioural differences between piribedil and L-dopa are reflected in the biochemical changes associated with the direct striatal output pathway. Administration of L-dopa or piribedil did not reverse the MPTP-induced up-regulation of preproenkephalin A mRNA in rostral or caudal areas of the putamen or caudate nucleus. In contrast, administration of either piribedil or L-dopa reversed the downregulation of preprotachykinin mRNA induced by MPTP in rostral and caudal striatum. L-dopa, but not Piribedil, reversed the decrease in preproenkephalin B mRNA produced by MPTP treatment.
mesh_terms: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000009:adverse effects*; D000818:Animals; D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001143:Arousal / Q000187:drug effects; D002144:Callithrix; D002421:Caudate Nucleus / Q000378:metabolism; D003342:Corpus Striatum / Q000378:metabolism; D046508:Culture Techniques; D004334:Drug Administration Schedule; D004409:Dyskinesia, Drug-Induced / Q000209:etiology*; D020820:Dyskinesias / Q000175:diagnosis* / Q000188:drug therapy* / Q000378:metabolism; D005260:Female; D017403:In Situ Hybridization; D007980:Levodopa / Q000009:adverse effects*; D008124:Locomotion / Q000187:drug effects; D008297:Male; D010891:Piribedil / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D012333:RNA, Messenger / Q000378:metabolism; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D000978:Antiparkinson Agents; D012333:RNA, Messenger; D007980:Levodopa; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D010891:Piribedil