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Intraventricular 5,7‐Dihydroxytryptamine Increases Thyrotropin‐Releasing Hormone Content in Regions of Rat Brain
Author(s) -
Manaker Scott,
Engber Thomas M.,
Knight Pamela B.,
Winokur Andrew
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb05561.x
Subject(s) - medicine , endocrinology , thyrotropin releasing hormone , hippocampal formation , neurotransmitter , chemistry , radioimmunoassay , brainstem , hippocampus , norepinephrine , 5,7 dihydroxytryptamine , hormone , central nervous system , dopamine , serotonin , serotonergic , receptor
Rats received intraventricular (i.v.t.) injections of 5,7‐dihydroxytryptamine (5,7‐DHT) (100–600 μg). Some animals also received intraperitoneal injections of the 5‐hydroxytryptamine uptake blocker fluoxetine (FX) (20 mg/kg) or the norepinephrine uptake blocker desmethylimipramine (DMI) (48 mg/kg) 30–90 min prior to i.v.t. 5,7‐DHT. Rats were killed between 2 and 35 days following i.v.t. 5,7‐DHT, brains were dissected, and regions were assayed for thyrotropin‐releasing hormone (TRH) by radioimmunoassay. Dose‐dependent increases in TRH content following i.v.t. 5,7‐DHT were noted in the brainstem and hippocampus. DMI pretreatment blocked the increase in hippocampal TRH, but not in brainstem TRH. FX pretreatment was ineffective in blocking any increases in TRH content. These results suggest differential regulation of regional TRH content by interactions with specific neurotransmitter systems.