Distribution of thyrotropin-releasing hormone (TRH) in the hippocampal formation as determined by radioimmunoassay
| Autor: | Shereen D. Farber, Walter C. Low, Michael J. Kubek, Albert Sattin, Timothy G. Hill, Janet Roepke |
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| Rok vydání: | 1989 |
| Předmět: |
Male
endocrine system medicine.medical_specialty endocrine system diseases Chemistry General Neuroscience Dentate gyrus Fornix Subiculum Radioimmunoassay Thyrotropin-releasing hormone Hippocampus Rats Inbred Strains Hippocampal formation Rats Endocrinology nervous system Internal medicine medicine Animals Thyrotropin-Releasing Hormone hormones hormone substitutes and hormone antagonists Hormone |
| Zdroj: | Neuroscience letters. 103(3) |
| ISSN: | 0304-3940 |
| Popis: | The distribution of thyrotropin-releasing hormone (TRH) in the hippocampal formation was determined using a radioimmunoassay (RIA) specific for TRH. RIA of hippocampal subregions revealed that the CA3 region of the hippocampal formation contained the highest amount of TRH, followed by intermediate levels in region CA1 and the dentate gyrus. The hilus and subiculum contained the lowest levels. The issue of whether hippocampal TRH is derived from extrinsic and/or intrinsic sources was evaluated by making lesions of the major subcortical afferent to the hippocampus, the fornix pathway. Analysis of the hippocampal formation by RIA revealed that the ventral hippocampus contains higher levels of TRH than the dorsal hippocampus (6.01 ± 0.62 pg/mg tissue weight vs 1.11 ± 0.19 pg/mg tissue weight). Lesions of the fornix produced significant decreases in ventral TRH to 52.9% of its control level and in dorsal TRH to 28.8% of its control level. The results from these studies suggest that (1) there is a differential distribution of TRH in the hippocampal formation, (2) the hippocampal formation might be composed of extrinsic and intrinsic sources of TRH, and (3) extrinsic sources of TRH might enter the hippocampus via the fornix pathway. In addition (4) the greater post-lesion decrement in ventral vs dorsal hippocampal TRH suggests that TRH fibers traversing the fornix innervate the ventral hippocampal formation in preference to its dorsal counterpart. |
| Databáze: | OpenAIRE |
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