Ventral striatal vs. accumbal (shell) mechanisms and non-cyclase-coupled dopamine D-1-like receptors in jaw movements

This study compared the effects of intraoerebral injections of the dopamine D-1-like receptor agents 3-methyl-6-chloro-7,8-dihydroxy 1-[3-methylphenyl ]-2,3,3,5-tetrahydro-1H-3-benzazepine (SK & F 83959) and [R]-3-methyl-7-chl oro-8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1 H-3-benzazepine (SCH 23390) int o the ventrolateral striatum or the shell of the nucleus accumbens on the s ynergistic induction of jaw movements by intravenous (i.v.) co-administrati on of [R]-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1 H-3-benzazepine (SK&F 38393)or SK&F 83959 with the dopamine D-2-like receptor agonist, quinpirol e, In the ventrolateral striatum, SCH 23390 and SK&F 83959 each blocked jaw movements induced by i.v. SK&F 38393 with quinpirole, while only SCH 23390 blocked i.v. SK&F 83959 with quinpirole. SCH 23390 was less effective in t he accumbens shell than in the ventrolateral striatum, and SK&F 83959 was i neffective to block i.v. SK&F 38393 with quinpirole, while neither SCH 2339 0 nor SK&F 83959 blocked i.v. SK&F 83959 with quinpirole. As SK&F 83959 inh ibits the stimulation of adenylyl cyclase via dopamine D-1A receptors but a cts as an agonist at a putative dopamine D-1-like receptor site not linked to cyclase, an important role is indicated for non-cyclase-coupled dopamine D-1-like receptor sites as well as dopamine D-1A receptors in the regulati on of jaw movements via dopamine D-1-like/D-2-like receptor synergism, part icularly in the ventrolateral striatum. (C) 2001 Elsevier Science B.V. All rights reserved.