Distribution of thyrotropin-releasing hormone (TRH) in the hippocampal formation as determined by radioimmunoassay

Walter C. Low; Janet Roepke; Shereen D. Farber; Timothy G. Hill; Albert Sattin; Michael J. Kubek

doi:10.1016/0304-3940(89)90119-5

Distribution of thyrotropin-releasing hormone (TRH) in the hippocampal formation as determined by radioimmunoassay

Walter C. Low, Janet Roepke, Shereen D. Farber, Timothy G. Hill, Albert Sattin, Michael J. Kubek

Neurosurgery

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Abstract

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.

Original language	English (US)
Pages (from-to)	314-319
Number of pages	6
Journal	Neuroscience Letters
Volume	103
Issue number	3
DOIs	https://doi.org/10.1016/0304-3940(89)90119-5
State	Published - Sep 11 1989

Bibliographical note

Funding Information:
The technical assistance of M. Zaphirou, S.H. Murphy, and J.L. Evan is gratefully acknowledged. This work was supported by grants from the Veterans Administration Medical Research Service (A.S. and M.J.K.), the Muscular Dystrophy Association (M.J.K.) and PHS Grants NS-25661 (M.J.K.) and AG-5575 (W.C.L.).

Keywords

Fornix pathway
Hippocampal formation
Thyrotropin-releasing hormone

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10.1016/0304-3940(89)90119-5

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title = "Distribution of thyrotropin-releasing hormone (TRH) in the hippocampal formation as determined by radioimmunoassay",

abstract = "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.",

keywords = "Fornix pathway, Hippocampal formation, Thyrotropin-releasing hormone",

author = "Low, {Walter C.} and Janet Roepke and Farber, {Shereen D.} and Hill, {Timothy G.} and Albert Sattin and Kubek, {Michael J.}",

note = "Funding Information: The technical assistance of M. Zaphirou, S.H. Murphy, and J.L. Evan is gratefully acknowledged. This work was supported by grants from the Veterans Administration Medical Research Service (A.S. and M.J.K.), the Muscular Dystrophy Association (M.J.K.) and PHS Grants NS-25661 (M.J.K.) and AG-5575 (W.C.L.).",

year = "1989",

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doi = "10.1016/0304-3940(89)90119-5",

language = "English (US)",

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T1 - Distribution of thyrotropin-releasing hormone (TRH) in the hippocampal formation as determined by radioimmunoassay

AU - Low, Walter C.

AU - Roepke, Janet

AU - Farber, Shereen D.

AU - Hill, Timothy G.

AU - Sattin, Albert

AU - Kubek, Michael J.

N1 - Funding Information: The technical assistance of M. Zaphirou, S.H. Murphy, and J.L. Evan is gratefully acknowledged. This work was supported by grants from the Veterans Administration Medical Research Service (A.S. and M.J.K.), the Muscular Dystrophy Association (M.J.K.) and PHS Grants NS-25661 (M.J.K.) and AG-5575 (W.C.L.).

PY - 1989/9/11

Y1 - 1989/9/11

N2 - 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.

AB - 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.

KW - Fornix pathway

KW - Hippocampal formation

KW - Thyrotropin-releasing hormone

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DO - 10.1016/0304-3940(89)90119-5

M3 - Article

C2 - 2510091

AN - SCOPUS:0024342294

SN - 0304-3940

VL - 103

SP - 314

EP - 319

JO - Neuroscience Letters

JF - Neuroscience Letters

IS - 3

ER -

Distribution of thyrotropin-releasing hormone (TRH) in the hippocampal formation as determined by radioimmunoassay

Abstract

Bibliographical note

Keywords

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