Selective blockade of serotonin 2C receptor enhances Fos expression specifically in the striatum and the subthalamic nucleus within the basal ganglia.
Serotonin(2C) (5-HT(2C)) receptors are widely expressed in the basal ganglia, a group of brain regions involved in the control of motor behavior. However, it remains unclear whether their tonic influence on neuronal activity is distributed in these regions. We have addressed this question by measuring the product of the proto-oncogene c-Fos in rats after peripheral administration of the non-selective 5-HT antagonist mianserin, the 5-HT(2C/2B) antagonist SER-082 or the selective 5-HT(2C) antagonist SB 243213. The intraperitoneal administration of 1mg/kg of SB 243213 or SER-082, but not mianserin, enhanced Fos-immunoreactive cells in the subthalamic nucleus and the striatum, primarily its medial portion. None of these treatments significantly affected Fos expression in the external globus pallidus, the entopeduncular nucleus (the internal globus pallidus in primate) or the substantia nigra pars reticulata. The data suggest that selective blockade of 5-HT(2C) receptors is necessary to unmask a tonic regulation of neuronal activity by this receptor in the basal ganglia and that this effect is restricted to the two structures receiving cortical entries, the striatum and the subthalamic nucleus.
De Deurwaerdère
Philippe
P
Université de Bordeaux, Unité Mixte de Recherche-Centre National de la Recherche Scientifique (UMR-CNRS) 5227, 146 rue Léo Saignat, B.P. 28, 33076 Bordeaux Cedex, France. deurwaer@u-bordeaux2.fr
Le Moine
Catherine
C
Chesselet
Marie-Françoise
MF
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D005917:Globus Pallidus / Q000187:drug effects / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D008297:Male; D008803:Mianserin / Q000494:pharmacology; D010784:Photomicrography; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044405:Receptor, Serotonin, 5-HT2C / Q000378:metabolism*; D058830:Serotonin 5-HT2 Receptor Antagonists; D012702:Serotonin Antagonists / Q000494:pharmacology*; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism; D020531:Subthalamic Nucleus / Q000187:drug effects* / Q000378:metabolism
D007211:Indoles; D016760:Proto-Oncogene Proteins c-fos; D011725:Pyridines; D044405:Receptor, Serotonin, 5-HT2C; D058830:Serotonin 5-HT2 Receptor Antagonists; D012702:Serotonin Antagonists; D008803:Mianserin; C406343:SB 243213