5-HT sub(2A) receptors are expressed by catecholaminergic neurons in the rat nucleus tractus solitarii

• Published in: Neuroreport Vol. 13; no. 17; pp. 2365 - 2369
• Main Authors: Nosjean, A, Hamon, M, Darmon, M
• Format: Journal Article
• Language: English
• Published: 01-12-2002
• ISSN: 0959-4965

Within the nucleus tractus solitarii (NTS), serotonin (5-HT) exerts modulatory effects on central mechanisms controlling autonomic functions, notably through the stimulation of 5-HT sub(2) receptors. Using double immunocytochemical labeling with specific anti-5-HT sub(2A) 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-HT sub(2A) receptors located on CA perikarya and/or processes within the NTS. A relatively high density of 5-HT sub(2A) immunoreactive processes was observed throughout the NTS. 5-HT sub(2A) neuronal perikarya were also found within the NTS except in its rostrolateral part. Double immunolabeling experiments revealed many 5-HT sub(2A) receptors on CA processes but only few 5-HT sub(2A)/TH and 5-HT sub(2A)/DBH perikarya. These data support the idea that, within the NTS, 5-HT sub(2A)-mediated control of autonomic functions involves CA neurons.