title: Effects of CB1 cannabinoid receptor modulating compounds on the hyperkinesia induced by high-dose levodopa in the reserpine-treated rat model of Parkinson's disease.
abstract: The present study was designed to determine the potential of CB1 cannabinoid receptor modulating compounds in the treatment of L-3,4-dihydroxyphenylalanine (L-dopa)-induced dyskinesia in Parkinson's disease. In the reserpine-treated rat model of parkinsonism, administration of a high dose of L-dopa (150 mg/kg) but not of Cl-APB (0.5 mg/kg) or quinpirole (0.5 mg/kg) produced a hyperkinetic state characterised by an increase in horizontal and vertical activity, which likely represent correlates of antiparkinsonian and dyskinetic activity, respectively. Injection of the CB1 cannabinoid receptor antagonist SR141716 (0.1-3 mg/kg) reduced the increase in vertical activity elicited by L-dopa without affecting the increase in horizontal activity. Injection of the CB1 cannabinoid receptor agonist WIN55,212-2 (0.1-3 mg/kg) reduced the L-dopa-induced increase in vertical activity and, at the highest dose only (3 mg/kg), also reduced horizontal activity elicited by L-dopa. WIN55,212-2 (1 mg/kg) reduced motor activity induced by both the D1 receptor agonist Cl-APB (0.5 mg/kg) and the D2 receptor agonist quinpirole (0.5 mg/kg) in the reserpine-treated rat. SR141716 (1 mg/kg) had no effects on motor activity induced by Cl-APB (0.5 mg/kg) nor quinpirole (0.5 mg/kg) in the reserpine-treated rat. Injection of the inhibitor of endocannabinoid transport AM404 (0.1-1 mg/kg) did not affect the increase in horizontal or vertical activity elicited by L-dopa (150 mg/kg) in the reserpine-treated rat. The data suggest that both CB1 cannabinoid receptor antagonists and agonists can modulate the behavioural effects of L-dopa and may be useful for the treatment of the dyskinesia associated with long-term L-dopa treatment of Parkinson's disease.
authors.affiliation: Division of Neuroscience, School of Biological Sciences, University of Manchester, Manchester, United Kingdom. segoviag@med.ucm.es
authors.forename: Gregorio
authors.initials: G
authors.lastname: Segovia
authors.forename: Francisco
authors.initials: F
authors.lastname: Mora
authors.forename: Alan R
authors.initials: AR
authors.lastname: Crossman
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Brotchie
mesh_terms: D018759:Adrenergic Uptake Inhibitors / Q000627:therapeutic use*; D000818:Animals; D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001522:Behavior, Animal / Q000187:drug effects; D063385:Cannabinoid Receptor Modulators; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D006948:Hyperkinesis / Q000139:chemically induced*; D007980:Levodopa / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D010300:Parkinson Disease / Q000188:drug therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000187:drug effects*; D012110:Reserpine / Q000627:therapeutic use*; D013997:Time Factors
chemical_list: D018759:Adrenergic Uptake Inhibitors; D000978:Antiparkinson Agents; D063385:Cannabinoid Receptor Modulators; D005231:Fatty Acids, Unsaturated; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D007980:Levodopa; D012110:Reserpine