Modulation of dopamine receptors by thyrotropin-releasing hormone in the rat brain

• Published in: Peptides (New York, N.Y. : 1980) Vol. 8; no. 2; pp. 319 - 325
• Main Authors: Funatsu, Kunihiko S., Inanaga, Kazutoyo
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.03.1987; Elsevier Science
• Subjects: [ 3H]Apomorphine binding; [ 3H]Spiperone binding; Animals; Apomorphine - metabolism; Biological and medical sciences; brain; Brain - metabolism; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; dopamine; Fundamental and applied biological sciences. Psychology; Kinetics; Male; Neuroleptics; Organ Specificity; Rats; Rats, Inbred Strains; Receptor-receptor interaction; Receptors, Dopamine - drug effects; Receptors, Dopamine - metabolism; Receptors, Neurotransmitter - metabolism; Receptors, Thyrotropin-Releasing Hormone; Spiperone - metabolism; thyroid-stimulating hormone-releasing hormone; Thyrotropin-Releasing Hormone - metabolism; Thyrotropin-Releasing Hormone - pharmacology; TRH receptors; Vertebrates: nervous system and sense organs; Receptor-receptor interaction; TRH receptors; [ 3H]Apomorphine binding; Neuroleptics; [ 3H]Spiperone binding; TSH-RH; Brain; Vertebrata; Mammalia; Fixation; Rat; Rodentia; Peptide hormone; Central nervous system; Neurotransmitter; Neuropeptide; Dopaminergic receptor
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/0196-9781(87)90107-0

Nanomolar concentration of thyrotropin-releasing hormone (TRH) in vitro caused a significant reduction of [ 3H]apomorphine binding sites (70% of the control) in the rat striatum and the limbic forebrain. [ 3H]Spiperone binding was not affected by TRH. On the other hand, dopamine and apomorphine displaced [ 3H]TRH binding partially, suggesting the presence of a TRH receptor subpopulation that has a high affinity for dopamine agonist. Most of the neuroleptics displaced [ 3H]TRH binding dose-dependently in the micromolar range. (−)-Sulpiride had no affinity to TRH receptors. These findings suggest that one of the important roles of TRH as a neuromodulator is to modulate receptors for classical neurotransmitters, and this receptor-receptor interaction may be of importance in explaining the well known stimulating effects of TRH on the dopaminergic system.