5-HT2A receptors are expressed by catecholaminergic neurons in the rat nucleus tractus solitarii.
Within the nucleus tractus solitarii (NTS), serotonin (5-HT) exerts modulatory effects on central mechanisms controlling autonomic functions, notably through the stimulation of 5-HT2 receptors. Using double immunocytochemical labeling with specific anti-5-HT2A receptor antibodies and antibodies directed against the catecholamine (CA) synthesizing enzymes, i.e. tyrosine hydroxylase, dopamine beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase, we investigated whether 5-HT effects could be mediated by 5-HT2A receptors located on CA perikarya and/or processes within the NTS. A relatively high density of 5-HT2A immunoreactive processes was observed throughout the NTS. 5-HT2A neuronal perikarya were also found within the NTS except in its rostrolateral part. Double immunolabeling experiments revealed many 5-HT2A receptors on CA processes but only few 5-HT2A/TH and 5-HT2A/DBH perikarya. These data support the idea that, within the NTS, 5-HT2A-mediated control of autonomic functions involves CA neurons.
Nosjean
Anne
A
INSERM U288, NeuroPsychoPharmacologie, Faculté de Médecine Pitié-Salpêtrière, 75634 Paris Cedex 13, France. nosjean@ext.jussieu.fr
Hamon
Michel
M
Darmon
Michèle
M
D000818:Animals; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D002395:Catecholamines / Q000378:metabolism*; D003712:Dendrites / Q000378:metabolism / Q000648:ultrastructure; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D008297:Male; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D017552:Solitary Nucleus / Q000166:cytology / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D002395:Catecholamines; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin; D012701:Serotonin; D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase; D010625:Phenylethanolamine N-Methyltransferase