Evidence for a dopaminergic innervation of the cat lateral habenula: its role in controlling serotonin transmission in the basal ganglia.
The presence of a dopaminergic innervation of the cat lateral habenula and its possible role in modulating serotonin transmission within the basal ganglia were investigated using both in vitro and in vivo approaches. A high density of [3H]spiroperidol binding sites with similar affinities for domperidone and apomorphine as those present in the cat striatum were found in the habenula. By means of the push-pull cannula technique, a substantial release of [3H]dopamine continuously formed from [3H]tyrosine was detected in the lateral habenula of halothane-anesthetized cats since the amount of [3H]catecholamines was enhanced in the presence of benztropine, an inhibitor of dopamine uptake into dopaminergic nerve terminals. Furthermore, in anesthetized animals with a push-pull cannula implanted in each caudate nucleus and substantia nigra habenular applications of dopamine (10(-7) M) reduced nigral but not striatal release of [3H]serotonin continuously formed from [3H]tryptophan. This change was prevented either by the delivery of domperidone to the lateral habenula or by the blockade of GABAergic transmission (picrotoxin 10(-5) M) in the dorsal raphe. These data support the involvement of habenulo-raphe pathways in the regulation of serotonin transmission in the cat basal ganglia and indicate that dopaminergic inputs to the lateral habenula participate in such a control.
D000818:Animals; D001479:Basal Ganglia / Q000378:metabolism*; D001667:Binding, Competitive; D002415:Cats; D002421:Caudate Nucleus / Q000502:physiology; D003342:Corpus Striatum / Q000502:physiology; D004294:Domperidone / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D007700:Kinetics; D008297:Male; D010852:Picrotoxin / Q000494:pharmacology; D011903:Raphe Nuclei / Q000187:drug effects / Q000502:physiology; D011954:Receptors, Dopamine / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D013134:Spiperone / Q000378:metabolism; D013788:Thalamus / Q000187:drug effects / Q000502:physiology*
D004294:Domperidone; D004298:Dopamine; D010852:Picrotoxin; D011954:Receptors, Dopamine; D012701:Serotonin; D013134:Spiperone; C031611:spiroperidol receptor