Intrastriatal injection of D1 or D2 dopamine agonists affects glucose utilization in both the direct and indirect pathways of the rat basal ganglia.
Two distinct pathways are thought to connect the striatum to the basal ganglia output nuclei: a direct pathway, originating from neurons bearing dopamine, D(1) receptors and an indirect pathway, originating from neurons expressing D(2) receptors. It has been recently suggested, however, that dopamine receptor sub-types may co-localize and co-operate in the striatum. We sought to verify the functional segregation of the two pathways by measuring cerebral glucose utilization following intrastriatal injection of selective D(1) (SKF 38393), D(2) (quinpirole), or non-selective indirect (amphetamine) and direct (apomorphine) dopamine agonists, in freely-moving rats. All drugs -- regardless of receptor selectivity -- reduced glucose utilization in nuclei of both the direct and indirect pathways, thus lending further support to the existence of a functional co-operation of striatal D(1) and D(2) receptors.
Conti
G
G
Neuromed Institute, Parco Tecnologico, 86077 (IS), Pozzilli, Italy.
Blandini
F
F
Tassorelli
C
C
Giubilei
F
F
Fornai
F
F
Zocchi
A
A
Orzi
F
F
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001479:Basal Ganglia / Q000187:drug effects / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology*; D020392:Entopeduncular Nucleus / Q000187:drug effects / Q000378:metabolism; D005917:Globus Pallidus / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D008297:Male; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D019257:Quinpirole / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000819:agonists* / Q000096:biosynthesis; D017448:Receptors, Dopamine D2 / Q000819:agonists* / Q000096:biosynthesis; D020531:Subthalamic Nucleus / Q000187:drug effects / Q000378:metabolism
D018491:Dopamine Agonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D019257:Quinpirole; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000661:Amphetamine; D005947:Glucose; D001058:Apomorphine