Autoradiographic localization of thyrotropin-releasing hormone receptors in the rat central nervous system.
We employed quantitative autoradiography to examine the distribution of thyrotropin-releasing hormone (TRH) receptors in the rat CNS. The binding of [3H]3-methyl-histidine-TRH [( 3H]MeTRH) to TRH receptors in frozen rat brain sections was saturable, of a high affinity (Kd = 5 nM), and specific for TRH analogs. Autoradiograms of [3H]MeTRH binding showed highest concentrations of TRH receptors in the rhinencephalon, including accessory olfactory bulb, nuclei of the amygdala, and the ventral dentate gyrus and subiculum of the hippocampus. Moderate TRH receptor concentrations were found within the thalamus and hypothalamus, in most regions of the rhombencephalon, such as the cranial nerve nuclei, and in the substantia gelatinosa of the spinal cord. Neocortex and basal ganglia contained low densities of TRH receptors. This distribution correlates well with the sensitivity of brain regions to the known effects of TRH, and suggests that TRH receptors may mediate the actions of TRH in the rat CNS.
Manaker
S
S
Winokur
A
A
Rostene
W H
WH
Rainbow
T C
TC
D000679:Amygdala / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D001933:Brain Stem / Q000378:metabolism; D002490:Central Nervous System / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D007700:Kinetics; D008032:Limbic System / Q000378:metabolism; D008297:Male; D009830:Olfactory Bulb / Q000378:metabolism; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018025:Receptors, Thyrotropin-Releasing Hormone; D012688:Septum Pellucidum / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism; D013788:Thalamus / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000378:metabolism; D014018:Tissue Distribution
D011956:Receptors, Cell Surface; D018025:Receptors, Thyrotropin-Releasing Hormone; C014109:thyrotropin-releasing hormone, 3-Me-; D013973:Thyrotropin-Releasing Hormone; D011761:Pyrrolidonecarboxylic Acid