title: CGP 56999A, a GABA(B) receptor antagonist, enhances expression of brain-derived neurotrophic factor and attenuates dopamine depletion in the rat corpus striatum following a 6-hydroxydopamine lesion of the nigrostriatal pathway.
abstract: Rats were injected (i.p.) once daily with either 1 mg/kg CGP 56999A, a gamma-aminobutyric acid(B) (GABA(B)) receptor antagonist, or an equivalent volume of saline beginning 7 days prior to, and continuing for 7 days following, a unilateral 6-hydroxydopamine lesion of the nigrostriatal dopamine (DA) pathway. At the end of the CGP 56999A treatment period the concentrations of DA and dihydroxyphenylacetic acid (DOPAC), as well as the expression of brain-derived neurotrophic factor (BDNF), were analyzed in corpus striatum ipsilateral and contralateral to the lesioning. No significant differences in these parameters were noted in the contralateral striatum between saline- and CGP 56999A-treated subjects. In contrast, as compared to animals receiving saline only, daily treatment with the GABA(B) receptor antagonist significantly attenuated the 6-hydroxydopamine-induced decline in DA and increased the expression of BDNF in the ipsilateral striatum. The results indicate that CGP 56999A enhances BDNF gene expression in the rat corpus striatum and prevents the decline in DA content that is a characteristic sequela of 6-hydroxydopapmine lesions of the nigrostraital dopamine pathway. These findings suggest that GABA(B) receptor antagonists may be of value in the treatment of Parkinson's disease and other conditions that would benefit from an enhanced production of neurotrophic factors in brain.
authors.affiliation: Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Enna
authors.forename: Scott A
authors.initials: SA
authors.lastname: Reisman
authors.forename: John A
authors.initials: JA
authors.lastname: Stanford
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000187:drug effects* / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D003714:Denervation; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D018756:GABA Antagonists / Q000627:therapeutic use*; D058788:GABA-B Receptor Antagonists; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000378:metabolism / Q000503:physiopathology; D016627:Oxidopamine; D020734:Parkinsonian Disorders / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D010721:Phosphinic Acids / Q000627:therapeutic use*; D051381:Rats; D011916:Rats, Inbred F344; D018080:Receptors, GABA-B / Q000378:metabolism; D013378:Substantia Nigra / Q000378:metabolism / Q000503:physiopathology; D013565:Sympatholytics; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C102659:CGP 56999A; D018756:GABA Antagonists; D058788:GABA-B Receptor Antagonists; D010721:Phosphinic Acids; D018080:Receptors, GABA-B; D013565:Sympatholytics; D015102:3,4-Dihydroxyphenylacetic Acid; D016627:Oxidopamine; D004298:Dopamine