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De La Cruz DL, Prokai L, Prokai-Tatrai K. The Antagonist pGlu-βGlu-Pro-NH 2 Binds to an Allosteric Site of the Thyrotropin-Releasing Hormone Receptor. Molecules 2021; 26:5397. [PMID: 34500828 PMCID: PMC8433856 DOI: 10.3390/molecules26175397] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/20/2021] [Accepted: 09/02/2021] [Indexed: 11/16/2022] Open
Abstract
After we identified pGlu-βGlu-Pro-NH2 as the first functional antagonist of the cholinergic central actions of the thyrotropin-releasing hormone (TRH, pGlu-His-Pro-NH2), we became interested in finding the receptor-associated mechanism responsible for this antagonism. By utilizing a human TRH receptor (hTRH-R) homology model, we first refined the active binding site within the transmembrane bundle of this receptor to enhance TRH's binding affinity. However, this binding site did not accommodate the TRH antagonist. This directed us to consider a potential allosteric binding site in the extracellular domain (ECD). Searches for ECD binding pockets prompted the remodeling of the extracellular loops and the N-terminus. We found that different trajectories of ECDs produced novel binding cavities that were then systematically probed with TRH, as well as its antagonist. This led us to establish not only a surface-recognition binding site for TRH, but also an allosteric site that exhibited a selective and high-affinity binding for pGlu-βGlu-Pro-NH2. The allosteric binding of this TRH antagonist is more robust than TRH's binding to its own active site. The findings reported here may shed light on the mechanisms and the multimodal roles by which the ECD of a TRH receptor is involved in agonist and/or antagonist actions.
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Affiliation(s)
| | | | - Katalin Prokai-Tatrai
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; (D.L.D.L.C.); (L.P.)
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Prokai-Tatrai K, Nguyen V, Prokai L. [β-Glu 2]TRH Is a Functional Antagonist of Thyrotropin-Releasing Hormone (TRH) in the Rodent Brain. Int J Mol Sci 2021; 22:ijms22126230. [PMID: 34207724 PMCID: PMC8226542 DOI: 10.3390/ijms22126230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 11/25/2022] Open
Abstract
Selective antagonists of thyrotropin-releasing hormone (TRH; pGlu-His-Pro-NH2), in order to enable a better understanding of this peptide’s central functions, have not been identified. Using pGlu-Glu-Pro-NH2 ([Glu2]TRH) as a lead peptide and with modification at its central residue, our studies focused on some of its analogues synthesized as potential functional antagonists of TRH in the rodent brain. Among the peptides studied, the novel isomeric analogue [β-Glu2]TRH was found to suppress the analeptic and antidepressant-like pharmacological activities of TRH without eliciting intrinsic effects in these paradigms. [β-Glu2]TRH also completely reversed TRH’s stimulation of acetylcholine turnover in the rat hippocampus without a cholinergic activity of its own, which was demonstrated through in vivo microdialysis experiments. Altogether, [β-Glu2]TRH emerged as the first selective functional antagonist of TRH’s prominent cholinergic actions, by which this endogenous peptide elicits a vast array of central effects.
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Kobayashi N, Sato N, Sugita K, Takahashi K, Sugawara T, Tada Y, Yoshikawa T. Synthesis and evaluation of in vivo anti-hypothermic effect of all stereoisomers of the thyrotropin-releasing hormone mimetic: Rovatirelin Hydrate. J Pept Sci 2019; 25:e3228. [PMID: 31713944 DOI: 10.1002/psc.3228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 11/06/2022]
Abstract
We discovered the orally active thyrotropin-releasing hormone (TRH) mimetic: (4S,5S)-5-methyl-N-{(2S)-1-[(2R)-2-methylpyrrolidin-1-yl]-1-oxo-3-(1,3-thiazol-4-yl)propan-2-yl}-2-oxo-1,3-oxazolidine-4-carboxamide 1 (rovatirelin). The central nervous system (CNS) effect of rovatirelin after intravenous (iv) administration is 100-fold higher than that of TRH. As 1 has four asymmetric carbons in its molecule, there are 16 stereoisomers. We synthesized and evaluated the anti-hypothermic effect of all stereoisomers of 1, which has the (4S),(5S),(2S),(2R) configuration from the N-terminus to the C-terminus, in order to clarify the structure-activity relationship (SAR) of stereoisomers. The (4R),(5R),(2R),(2S)-isomer 16 did not show any anti-hypothermic effect. Only the (4S),(5S),(2S),(2S)-isomer 10, which has the (2S)-2-methylpyrrolidine moiety at the C-terminus showed the anti-hypothermic effect similar to 1. Stereoisomers, which have the (5R) configuration of the oxazolidinone at the N-terminus and the (2R) configuration at the middle-part, showed a much lower anti-hypothermic effect than that of 1. On the other hand, stereoisomers, which have the (4R) configuration of the oxazolidinone at the N-terminus or the (2S) configuration of the C-terminus, have little influence on the anti-hypothermic effect.
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Affiliation(s)
- Naotake Kobayashi
- Medicinal chemistry research laboratory, Shionogi & Co., Ltd. 3-1-1, Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Norihito Sato
- Research Laboratory for Development, Shionogi & Co., Ltd. 3-1-1, Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Katsuji Sugita
- Research Laboratory for Development, Shionogi & Co., Ltd. 3-1-1, Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Kouji Takahashi
- DMPK Services, Shionogi Techno Advance Research Co., Ltd. 3-1-1, Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Tamio Sugawara
- Medicinal chemistry research laboratory, Shionogi & Co., Ltd. 3-1-1, Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Yukio Tada
- Medicinal chemistry research laboratory, Shionogi & Co., Ltd. 3-1-1, Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Takayoshi Yoshikawa
- Pharmacovigilance Japan, Allergan Japan K.K., 4-20-3-35, Ebisu Shibuya-ku, Tokyo, 150-6035, Japan
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Kobayashi N, Sato N, Fujimura Y, Kihara T, Sugita K, Takahashi K, Koike K, Sugawara T, Tada Y, Nakai H, Yoshikawa T. Discovery of the Orally Effective Thyrotropin-Releasing Hormone Mimetic: 1-{ N-[(4 S,5 S)-(5-Methyl-2-oxooxazolidine-4-yl)carbonyl]-3-(thiazol-4-yl)-l-alanyl}-(2 R)-2-methylpyrrolidine Trihydrate (Rovatirelin Hydrate). ACS OMEGA 2018; 3:13647-13666. [PMID: 30411045 PMCID: PMC6217654 DOI: 10.1021/acsomega.8b01481] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/25/2018] [Indexed: 06/01/2023]
Abstract
We have explored orally effective thyrotropin-releasing hormone (TRH) mimetics, showing oral bioavailability and brain penetration by structure-activity relationship (SAR) study on the basis of in vivo antagonistic activity on reserpine-induced hypothermia in mice. By primary screening of the synthesized TRH mimetics, we found a novel TRH mimetic: l-pyroglutamyl-[3-(thiazol-4-yl)-l-alanyl]-l-prolinamide with a high central nervous system effect compared with TRH as a lead compound. Further SAR optimization studies of this lead compound led to discovery of a novel orally effective TRH mimetic: 1-{N-[(4S,5S)-(5-methyl-2-oxooxazolidine-4-yl)carbonyl]-3-(thiazol-4-yl)-l-alanyl}-(2R)-2-methylpyrrolidine trihydrate (rovatirelin hydrate), which was selected as a candidate for clinical trials.
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Affiliation(s)
- Naotake Kobayashi
- Medicinal
Chemistry Research Laboratory, Research Laboratory for Development, and Drug Discovery
& Disease Research Laboratory, Shionogi
& Co., Ltd., 3-1-1,
Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Norihito Sato
- Medicinal
Chemistry Research Laboratory, Research Laboratory for Development, and Drug Discovery
& Disease Research Laboratory, Shionogi
& Co., Ltd., 3-1-1,
Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Yuko Fujimura
- Medicinal
Chemistry Research Laboratory, Research Laboratory for Development, and Drug Discovery
& Disease Research Laboratory, Shionogi
& Co., Ltd., 3-1-1,
Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Tsuyoshi Kihara
- Business
Search & Evaluation, Shionogi &
Co., Ltd., 3-1-8, Doshomachi, Chuo-ku, Osaka-shi, Osaka 541-0045, Japan
| | - Katsuji Sugita
- Medicinal
Chemistry Research Laboratory, Research Laboratory for Development, and Drug Discovery
& Disease Research Laboratory, Shionogi
& Co., Ltd., 3-1-1,
Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Kouji Takahashi
- DMPK
Services, Shionogi Techno Advance Research
Co., Ltd., 3-1-1, Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Katsumi Koike
- Medicinal
Chemistry Research Laboratory, Research Laboratory for Development, and Drug Discovery
& Disease Research Laboratory, Shionogi
& Co., Ltd., 3-1-1,
Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Tamio Sugawara
- Medicinal
Chemistry Research Laboratory, Research Laboratory for Development, and Drug Discovery
& Disease Research Laboratory, Shionogi
& Co., Ltd., 3-1-1,
Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Yukio Tada
- Medicinal
Chemistry Research Laboratory, Research Laboratory for Development, and Drug Discovery
& Disease Research Laboratory, Shionogi
& Co., Ltd., 3-1-1,
Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Hiroshi Nakai
- Medicinal
Chemistry Research Laboratory, Research Laboratory for Development, and Drug Discovery
& Disease Research Laboratory, Shionogi
& Co., Ltd., 3-1-1,
Futaba-cho, Toyonaka-shi, Osaka 561-0825, Japan
| | - Takayoshi Yoshikawa
- Pharmacovigilance
Japan, Allergan Japan K.K., 4-20-3-35, Ebisu, Shibuya-ku, Tokyo 150-6035, Japan
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5
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Yarbrough G, Kamath J, Winokur A, Prange A. Thyrotropin-releasing hormone (TRH) in the neuroaxis: Therapeutic effects reflect physiological functions and molecular actions. Med Hypotheses 2007; 69:1249-56. [DOI: 10.1016/j.mehy.2007.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Accepted: 04/03/2007] [Indexed: 10/23/2022]
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Nguyen V, Zharikova AD, Prokai L. Evidence for interplay between thyrotropin-releasing hormone (TRH) and its structural analogue pGlu-Glu-Pro-NH2 ([Glu2]TRH) in the brain: an in vivo microdialysis study. Neurosci Lett 2006; 415:64-7. [PMID: 17234338 DOI: 10.1016/j.neulet.2006.12.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 12/19/2006] [Accepted: 12/26/2006] [Indexed: 11/18/2022]
Abstract
Local perfusion of pGlu-Glu-Pro-NH2, an endogenous peptide structurally related to thyrotropine-releasing hormone (TRH), via in vivo microdialysis into the rat hippocampus did not change the basal level of extracellular acetylcholine. However, co-perfusion of pGlu-Glu-Pro-NH2 with TRH in equimolar concentrations yielded a significant attenuation of TRH-induced acetylcholine release. The results have supported the study's hypothesis that pGlu-Glu-Pro-NH2 opposes the cholinergic effect of TRH in the mammalian central nervous system. The enantiomer pGlu-d-Glu-Pro-NH2 affected neither basal extracellular nor TRH-induced increase of acetylcholine levels.
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Affiliation(s)
- Vien Nguyen
- Department of Molecular Biology & Immunology, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA
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Prokai L, Prokai-Tatrai K, Zharikova AD, Nguyen V, Perjesi P, Stevens SM. Centrally Acting and Metabolically Stable Thyrotropin-Releasing Hormone Analogues by Replacement of Histidine with Substituted Pyridinium. J Med Chem 2004; 47:6025-33. [PMID: 15537357 DOI: 10.1021/jm020531t] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metabolically stable and centrally acting thyrotropin-releasing hormone (TRH) analogues were designed by replacing the central histidine with substituted pyridinium moieties. Their analeptic and acetylcholine-releasing actions were evaluated to assess their potency as central nervous system (CNS) agents. A strong experimental connection between these two CNS-mediated actions of the TRH analogues was obtained in subject animals. The analogue 3-(aminocarbonyl)-1-(3-[2-(aminocarbonyl)pyrrolidin-1-yl]-3-oxo-2-[[(5-oxopyrrolidin-2-yl)carbonyl]amino]propyl)pyridinium (1a) showed the highest (TRH-equivalent) potency and longest, dose-dependent duration of action from a series of homologous compounds in antagonizing pentobarbital-induced narcosis when administered intravenously in its CNS-permeable prodrug form (2a) obtained via reduction of the pyridinium moiety to the nonionic dihydropyridine. The maximum change in hippocampal acetylcholine concentration upon perfusion of the pyridinium-containing tripeptides into the hippocampus of rats was also achieved with 1a. No binding to the endocrine TRH receptor was measured for the TRH analogues reported here; therefore, our design afforded a novel lead for centrally acting TRH analogues. We have also demonstrated the benefits of the prodrug approach on the pharmacokinetics and brain uptake/retention of pyridinium-containing TRH analogues (measured by in vivo microdialysis sampling) upon systemic administration.
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Affiliation(s)
- Laszlo Prokai
- Department of Medicinal Chemistry, Department of Pharmacology and Therapeutics, and The McKnight Brain Institute, University of Florida, Gainesville, Florida 32610, USA.
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Gary KA, Sevarino KA, Yarbrough GG, Prange AJ, Winokur A. The thyrotropin-releasing hormone (TRH) hypothesis of homeostatic regulation: implications for TRH-based therapeutics. J Pharmacol Exp Ther 2003; 305:410-6. [PMID: 12606661 DOI: 10.1124/jpet.102.044040] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The functions of thyrotropin-releasing hormone (TRH) in the central nervous system (CNS) can be conceptualized as performed by four anatomically distinct components that together comprise a general TRH homeostatic system. These components are 1) the hypothalamic-hypophysiotropic neuroendocrine system, 2) the brainstem/midbrain/spinal cord system, 3) the limbic/cortical system, and 4) the chronobiological system. We propose that the main neurobiological function of TRH is to promote homeostasis, accomplished through neuronal mechanisms resident in these four integrated systems. This hypothesis offers a unifying basis for understanding the myriad actions of TRH and TRH-related drugs already demonstrated in animals and humans. It is consistent with the traditional role of TRH as a regulator of metabolic homeostasis. An appreciation of the global function of TRH to modulate and normalize CNS activity, along with an appreciation of the inherent limitations of TRH itself as a therapeutic agent, leads to rational expectations of therapeutic benefit from metabolically stable TRH-mimetic drugs in a remarkably broad spectrum of clinical situations, both as monotherapy and as an adjunct to other therapeutic agents. The actions of TRH are numerous and varied. This has been viewed in the past as a conceptual and practical impediment to the development of TRH analogs. Herein, we alternatively propose that these manifold actions should be considered as a rational and positive impetus to the development of TRH-based drugs with the potential for unique and widespread applicability in human illness.
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Affiliation(s)
- Keith A Gary
- Department of Psychiatry, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 06030-6415, USA
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9
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Prokai L. Central nervous system effects of thyrotropin-releasing hormone and its analogues: opportunities and perspectives for drug discovery and development. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2003; 59:133-69. [PMID: 12458966 DOI: 10.1007/978-3-0348-8171-5_5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Besides its well-known endocrine role in the thyroid system, thyrotropin-releasing hormone (L-pyroglutamyl-L-histidyl-L-prolinamide) has been long recognized as a modulatory neuropeptide. After a brief overview of the extrahypothalamic and receptor distribution, and of the neurophysiological, neuropharmacological and neurochemical effects of this tripeptide, this review discusses efforts devoted to enhance therapeutically beneficial central nervous system effects via structural modifications of the endogenous peptide. An enormous array of maladies affecting the brain and the spinal cord has been a potential target for therapeutic interventions involving agents derived from thyrotropin-releasing hormone as a molecular lead. Successful development of several centrally active analogues and recent accounts of efforts aimed at improving metabolic stability, selectivity and bioavailability are highlighted.
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Affiliation(s)
- Laszlo Prokai
- Center for Drug Discovery, College of Pharmacy, and the McKnight Brain Institute, University of Florida Health Science Center, Gainesville, FL 32610-0497, USA
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Wu J, Yoon SH, Wu WM, Bodor N. Synthesis and biological evaluations of brain-targeted chemical delivery systems of [Nva2]-TRH. J Pharm Pharmacol 2002; 54:945-50. [PMID: 12162713 DOI: 10.1211/002235702760089063] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Various chemical delivery systems for [Nva2]-TRH were synthesized and their CNS activity was investigated and compared with that of a similar chemical delivery system of [Leu2]-TRH, previously studied. Sequential metabolism of the chemical delivery system delivered to the brain, starting with the conversion of the dihydrotrigonellyl (DHT) to the trigonellyl (T+) moiety, will provide the lock-in to the brain of the T+-chemical delivery system, which will undergo hydrolysis of the cholesteryl ester, formation of the Pr-amide and cleavage of the spacer-T+ part, allowing ultimately the sustained release of the active [Nva2]-TRH. The CNS activity was assessed by measuring the extent of antagonizing barbiturate-induced sleeping time in mice. The fully packaged DHT-Pro-Pro-Gln-Nva-Pro-Gly-OCh produced robust antagonism, reducing sleeping time from 89 min to 48 min, similar to the Leu2-analogue (49 min). However, the partially substituted [Nva2]-TRH analogues showed little or no CNS activity. The results indicate that the fully packaged delivery system is necessary to produce the successful brain targeting of the precursor construct and effective release of the Gln-Nva-ProNH2.
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Affiliation(s)
- Jiaxiang Wu
- Center for Drug discovery, College of Pharmacy, University of Florida, Gainesville 32611, USA
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11
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Synthesis and Brain Targeted Chemical Delivery of [Nva 2, Pip 3]-TRH. B KOREAN CHEM SOC 2002. [DOI: 10.5012/bkcs.2002.23.5.761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Hruby VJ, Qui W, Okayama T, Soloshonok VA. Design of nonpeptides from peptide ligands for peptide receptors. Methods Enzymol 2002; 343:91-123. [PMID: 11665597 DOI: 10.1016/s0076-6879(02)43129-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Affiliation(s)
- Victor J Hruby
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA
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13
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Prokai L, Prokai-Tatrai K, Ouyang X, Kim HS, Wu WM, Zharikova A, Bodor N. Metabolism-based brain-targeting system for a thyrotropin-releasing hormone analogue. J Med Chem 1999; 42:4563-71. [PMID: 10579819 DOI: 10.1021/jm980526i] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gln-Leu-Pro-Gly, a progenitor sequence for the thyrotropin-releasing hormone (TRH) analogue [Leu(2)]TRH (pGlu-Leu-Pro-NH(2)), was covalently and bioreversibly modified on its N- and C-termini (by a 1,4-dihydrotrigonellyl and a cholesteryl group, respectively) to create lipoidal brain-targeting systems for the TRH analogue. The mechanism of targeting and the recovery of the parent peptide at the target site involve several enzymatic steps, including the oxidation of the 1,4-dihydropyridine moiety. Due to the lipid insolublity of the peptide pyridinium conjugate obtained after this reaction, one of the rudimentary steps of brain targeting (i.e., trapping in the central nervous system) can be accomplished. Our design also included spacer amino acid(s) inserted between the N-terminal residue of the progenitor sequence and the dihydrotrigonellyl group to facilitate the posttargeting removal of the attached modification. The release of the TRH analogue in the brain is orchestrated by a sequential metabolism utilizing esterase/lipase, peptidyl glycine alpha-amidating monooxygenase (PAM), peptidase cleavage, and glutaminyl cyclase. In addition to in vitro experiments to prove the designed mechanism of action, the efficacy of brain targeting for [Leu(2)]TRH administered in the form of chemical-targeting systems containing the embedded progenitor sequence was monitored by the antagonistic effect of the peptide on the barbiturate-induced anesthesia (measure of the activational effect on cholinergic neurons) in mice, and considerable improvement was achieved over the efficacy of the parent peptide upon using this paradigm.
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Affiliation(s)
- L Prokai
- Center for Drug Discovery, College of Pharmacy, University of Florida, Gainesville, Florida 32610-0497, USA
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14
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Bauer K, Schomburg L, Heuer H, Schäfer MK. Thyrotropin releasing hormone (TRH), the TRH-receptor and the TRH-degrading ectoenzyme; three elements of a peptidergic signalling system. Results Probl Cell Differ 1999; 26:13-42. [PMID: 10453458 DOI: 10.1007/978-3-540-49421-8_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Affiliation(s)
- K Bauer
- Max-Planck-Institut für experimentelle Endokrinologie, Hannover, Germany
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15
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Abstract
A 55-year-old man presented with excessive daytime sleepiness and a circadian rhythm sleep disorder. Magnetic resonance imaging of the brain revealed a pontine lesion distinguishable from major cerebrovascular disease, demyelination and neoplasm. Benzodiazepines, antidepressants, methylcobalamine and thyroxine failed to synchronize the circadian rhythm. Antiepileptic drugs aggravated the condition, while melatonin and protireline partially relieved the patient from poorly controlled sleep disorder. A pontine lesion appeared to be related to the circadian rhythm sleep disorder of the patient.
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Affiliation(s)
- K Kashihara
- Department of Neurology, Okayama University Medical School, 2-5-1 Shitaka-cho, Okayama 700-0914, Japan
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16
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Lestage P, Iris-Hugot A, Gandon MH, Lepagnol J. Involvement of nicotinergic mechanisms in thyrotropin-releasing hormone-induced neurologic recovery after concussive head injury in the mouse. Eur J Pharmacol 1998; 357:163-9. [PMID: 9797032 DOI: 10.1016/s0014-2999(98)00562-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A behavioral study was performed in an attempt to understand the neuronal mechanisms involved in the thyrotropin-releasing hormone (TRH)-induced improvement of consciousness after concussive head injury in the mouse. Intravenous administration of TRH dose dependently shortened the duration of unconsciousness after concussion in the mouse (ED50 = 3.2 mg/kg). The improvement of recovery evoked by TRH (3 mg/kg i.v.) after concussion was not affected by i.p. pretreatment with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine, alpha-methyl-para-tyrosine, p-chlorophenylalanine, scopolamine or methylscopolamine. However, mecamylamine or hexamethonium i.p. pretreatment completely inhibited the TRH-induced improvement of outcome in traumatic brain injury. The results imply that TRH-induced improvement of recovery after concussion is not associated with increased activity of monoaminergic neurons in the brain. These results suggest that the inhibitory effect of TRH upon unconsciousness after concussion in mice is mainly produced by activation of central cholinergic systems via nicotinic receptors whereas muscarinic receptors seem to be not implicated.
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Affiliation(s)
- P Lestage
- Division of Cerebral Pathology, Institut de Recherches SERVIER, Croissy-sur-Seine, France
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Fukao K, Momiyama T, Ishihara K, Ujihara H, Fujita Y, Taniyama K, Serikawa T, Sasa M. Inhibition by gamma-aminobutyric acid system activation of epileptic seizures in spontaneously epileptic rats. JAPANESE JOURNAL OF PHARMACOLOGY 1998; 76:387-96. [PMID: 9623717 DOI: 10.1254/jjp.76.387] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The effects of muscimol, a gamma-aminobutyric acid (GABA)A-receptor agonist, and aminooxy-acetic acid (AOAA), an inhibitor of GABA-converting enzyme, on tonic and absence-like seizures in spontaneously epileptic rats (SER: zi/zi, tm/tm) were investigated to elucidate whether GABAergic function operates normally in these animals. Muscimol at doses of 1 and 3 mg/kg (i.p.) induced high-voltage slow waves in the cortical and hippocampal EEG of SER, although the behavioral observation suggested inhibition of absence-like seizures. Similar high-voltage slow waves were also observed in the cortical and hippocampal EEG of normal rats with muscimol (1 and 3 mg/kg). Tonic convulsions in SER were dose-dependently inhibited by muscimol. AOAA (3 and 10 mg/kg, i.v.) inhibited both tonic and absence-like seizures in SER, although there were no obvious changes in EEG pattern. The inhibitory effects of AOAA on tonic convulsions appeared more slowly and lasted longer than those on absence-like seizures. Cerebral, hippocampal and cerebellar GABA levels were significantly higher in SER than the normal Kyo:Wistar and zitter rat (zi/zi), which were both the parent strains. These findings suggest that GABA receptors and GABAergic neurons are functional in SER and that the GABA system is involved in the inhibition of both seizures.
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Affiliation(s)
- K Fukao
- Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan
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18
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Heuer H, Ehrchen J, Bauer K, Schäfer MK. Region-specific expression of thyrotrophin-releasing hormone-degrading ectoenzyme in the rat central nervous system and pituitary gland. Eur J Neurosci 1998; 10:1465-78. [PMID: 9749801 DOI: 10.1046/j.1460-9568.1998.00158.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Thyrotrophin-releasing hormone (TRH), a hypothalamic neuropeptide hormone and a putative neuromodulator/ neurotransmitter in the central nervous system is inactivated by the TRH-degrading ectoenzyme (TRH-DE), a TRH-specific metallopeptidase localized on the surface of neuronal brain cells in culture and on lactotrophic cells of the pituitary. After succeeding in cloning the cDNA of TRH-DE we now report on the cellular distribution pattern of this enzyme in rat brain, spinal cord and pituitary gland using in situ hybridization histochemistry. In the pituitary, TRH-DE mRNA was found both in the anterior and the neural lobe but not in the intermediate lobe. After treatment with triiodothyronine (T3) a dramatic increase in the mRNA levels of the TRH-DE and a decrease in the intensity of the TRH receptor could be observed in the anterior lobe of the pituitary. In brain, TRH-DE transcripts were predominantly found in neo- and allocortical regions with strongest signals in the olfactory bulb, the piriform cortex, the cerebral cortex, the granular layer of the cerebellar cortex and the pyramidal cells of the Ammon's horn. In the diencephalon, the highest TRH-DE mRNA levels were observed in the medial habenulae followed by several hypothalamic subregions. In the mesencephalon and brainstem, moderate signals were present in the superior colliculi, substantia nigra, dorsal raphe and in the periolivar region. In the spinal cord, TRH-DE mRNA positive neurons were present in all layers. The very distinct distribution of TRH-DE in the brain and the hormonal regulation of the adenohypophyseal enzyme support the concept that this peptidase serves very specialized functions.
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Affiliation(s)
- H Heuer
- Max-Planck-Institut für experimentelle Endokrinologie, Hannover, Germany
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Mazurov AA, Andronati SA, Korotenko TI, Sokolenko NI, Dyadenko AI, Shapiro YE, Voronina TA. TRH mimetics: differentiation of antiamnesic potency from antidepressant effect. Bioorg Med Chem 1997; 5:2029-40. [PMID: 9416420 DOI: 10.1016/s0968-0896(97)00141-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
For the purpose of rational modification of the TRH molecule, we were pursuing an approach that consists of two steps: (1) 'obligatory' replacement of histidine with glutamine in TRH and (2) the application of conformational constraints for putative bioactive conformation I stabilized by an intramolecular hydrogen bond between C-terminal carboxamide proton and alpha-carbonyl of histidyl (glutaminyl), and conformation II formed by an intramolecular hydrogen bond between alpha-carbonyl of pyroglutamyl and prolinamide proton. Significant antiamnesic potency was discovered in the passive avoidance test (ECS and Scopolamine induced amnesia) for conformation II mimic (8S,10aS)-8-carbamoyl-1,2,3,6,7,8,9,10a- octahydro-5H,10H-pyrrolo[1,2-a][1,4]diazocin-5,10-dione (2) at doses of 0.1 and 1.0 mg/kg. EEG analysis indicates a mild activating effect of compound 2 on EEG, which is similar to that of piracetam and differs from hard amphetamine activation. Conformation I mimic 3-(2-carbamoylethyl)-2,3,6,7,8,8a-hexahydro-1H,4H-pyrrolo[1,2-a] pyrazin-1,4-dione (1) exhibited an antidepressant effect at a dose of 1 mg/kg. The transition from two putative quasi-cyclic bioactive conformations of TRH and its obligatory similar analogue [Gln2]-TRH to their cyclic mimics led to differentiation of antiamnesic and antidepressant activity of TRH.
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Affiliation(s)
- A A Mazurov
- Physico-Chemical Institute, National Academy of Sciences, Odessa, Ukraine
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20
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Abstract
Recent evidence indicates that, in addition to the involvement of cholinergic and other neurotransmitter systems, various neuropeptides that occur in cortical and subcortical brain regions have a role in cognitive behavior. This evidence results largely from behavioral studies in rodents and other animals, following peptide administration and only in a very few cases from similar studies in human subjects. Several neuropeptides studied appear to enhance or produce changes conducive to improvement in cognitive performance and these include vasopressin, corticotrophin-releasing hormone (CRH), somatostatin, substance P, neuropeptide Y, and thyrotrophin-releasing hormone (TRH), while one peptide, galanin, has been reported to inhibit cognitive processes. Of those neuropeptides that improve performance, only TRH has been shown recently to attenuate the memory impairment of human subjects and Alzheimer patients treated with an anticholinergic drug, and this review describes a series of complimentary studies in adult and aged rodents that contribute to our understanding of the possible mechanisms involved in the role of TRH in cognition.
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Affiliation(s)
- G W Bennett
- Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, United Kingdom
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21
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Mazurov AA, Andronati SA, Korotenko TI, Sokolenko NI, Dyadenko AI, Shapiro YE, Gorbatyuk VY, Voronina TA. Design of a novel cognitive enhancer (8S, 10aS)-8-carbamoyl-1,2,3,6,7,8,9,10a-octahydro-5H,10H-pyrrolo[1,2-a][1,4]diazocin-5,10-dione. Bioorg Med Chem Lett 1996. [DOI: 10.1016/0960-894x(96)00478-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Itoh Y, Yamazaki A, Ukai Y, Yoshikuni Y, Kimura K. Enhancement of brain noradrenaline and dopamine turnover by thyrotropin-releasing hormone and its analogue NS-3 in mice and rats. PHARMACOLOGY & TOXICOLOGY 1996; 78:421-8. [PMID: 8829205 DOI: 10.1111/j.1600-0773.1996.tb00230.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effects of intravenous injections of thyrotropin-releasing hormone and its analog NS-3 (montirelin hydrate, CG3703) on the dynamics of brain monoamines were examined in mice and rats. In mice, both NS-3 (0.1-1 mg/kg) and thyrotropin-releasing hormone (10 and 30 mg/kg) increased the concentrations of 4-hydroxy-3-methoxyphenylglycol, 3,4-dihydroxyphenylacetic acid and homovanillic acid. The turnover rates, estimated either by depletion of catecholamines after treatment with alpha-methyl-p-tyrosine or by probenecid-induced accumulation of homovanillic acid, were enhanced by these peptides. In contrast, none of the compounds had any influence on the serotonin turnover. In rats, both NS-3 and thyrotropin-releasing hormone produced a regionally specific increase in the concentrations of the catecholamine metabolites. A microdialysis study demonstrated that NS-3 significantly increased the release of dopamine in the nucleus accumbens as well as the striatum of conscious rats, while thyrotropin-releasing hormone caused a weak but significant enhancement of dopamine release only in the nucleus accumbens. These findings indicate that NS-3 was far more potent than thyrotropin-releasing hormone in facilitating the turnover of catecholamines without affecting serotonin turnover in the mouse and rat brain.
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Affiliation(s)
- Y Itoh
- Nippon Shinyaku Co., Ltd., Kyoto, Japan
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23
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Itoh Y, Sugimoto T, Ukai Y, Morino A, Kimura K. Permeability of NS-3, a thyrotropin-releasing hormone analogue, into the brain after its systemic administration in rats: a microdialysis study. J Pharm Pharmacol 1995; 47:833-6. [PMID: 8583352 DOI: 10.1111/j.2042-7158.1995.tb05750.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The concentration of NS-3 (montirelin hydrate, CG 3703), a thyrotropin-releasing hormone (TRH) analogue, in the cerebral cortex of urethane-anaesthetized rats was measured after its systemic administration (1 mg kg-1, i.v.), using in-vivo microdialysis coupled with a radioimmunoassay. The concentration in microdialysates was highest (24 nM) during the first 20 min after injection, and it fell below the detection limit (3.5 nM) 100 min after treatment. The maximal interstitial concentration was estimated to be 0.51 microM. From these results, it is suggested that NS-3 can readily penetrate into the brain.
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Affiliation(s)
- Y Itoh
- Research Laboratories, Nippon Shinyaku Co., Ltd., Kyoto, Japan
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24
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Murphy SM, Pilowsky PM, Sun QJ, Llewellyn-Smith IJ. Thyrotropin-releasing hormone-immunoreactive varicosities synapse on rat phrenic motoneurons. J Comp Neurol 1995; 359:310-22. [PMID: 7499531 DOI: 10.1002/cne.903590209] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The relationship between retrogradely labelled or intracellularly filled phrenic motoneurons and varicosities containing thyrotropin-releasing hormone immunoreactivity was investigated in rats by light and electron microscopy. Phrenic motoneurons were identified via retrograde tracing from the diaphragm with cholera toxin B subunit, which was followed by immunocytochemistry to visualise retrogradely labelled motoneurons and thyrotropin-releasing hormone-immunoreactive nerve fibres in their vicinity. At the light microscopic level, varicose thyrotropin-releasing hormone-immunoreactive nerve fibres were distributed sparsely in the phrenic motor nucleus, with some axons surrounding retrogradely labelled motoneurons. In separate intracellular experiments, four phrenic motoneurons identified by antidromic activation from the C5 phrenic nerve root were subsequently filled with Neurobiotin, and nerve fibres that contained thyrotropin-releasing hormone immunoreactivity were identified by immunocytochemistry. The numbers and locations of thyrotropin-releasing hormone-immunoreactive varicosities that were closely appeared to the intracellularly labelled motoneurons were mapped using a camera lucida technique. Close appositions by thyrotropin-releasing hormone-immunoreactive varicosities were seen on somata as well as on proximal and distal dendrites. The closely apposed varicosities were usually present in tight clusters, which were formed by single varicose axons. However, the distribution was nonuniform, in that some dendrites did not receive any close appositions. Ultrastructural analysis of random ultrathin sections through retrogradely labelled neurons showed that varicosities with thyrotropin-releasing hormone immunoreactivity made 1.8% of all synapses and direct contacts on somata and 2.3% of synapses and contacts with dendrites of the retrogradely labelled phrenic motoneurons. The results of these experiments suggest that thyrotropin-releasing hormone-immunoreactive varicosities provide similar numbers of inputs to both the somata and dendrites of phrenic motoneurons. These thyrotropin-releasing hormone-containing inputs seen via light and electron microscopy could modulate the excitability of phrenic motoneurons.
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Affiliation(s)
- S M Murphy
- Department of Medicine, Flinders Medical Centre, Bedford Park, South Australia, Australia
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25
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Abstract
Teleologically, pain is of paramount importance for survival and induces the organism to cope in an active way with aggressions from a basically hostile environment. While the activation of endogenous analgesic (opioid) systems typically occurs in conditions of surrender (pre-terminal conditions, sustained tortures, etc.), the activation of endogenous anti-analgesic systems triggers mechanisms of active or passive defence (such as camouflage) aimed at survival. The distinctive features of the main anti-analgesic systems (melanocortinergic, cholecystokininergic, thyroliberinergic) and the dramatic results obtained in experimental pre-terminal conditions (hemorrhagic shock, prolonged respiratory arrest) with the administration of their neuropeptide transmitters (ACTH and several ACTH-fragments, including alpha-MSH, CCK peptides and thyrotropin-releasing hormone) are here reviewed. The study of the mechanisms underlying the resuscitating effects of these neuropeptides has led to the discovery of the (often extremely potent) resuscitating effect of other drugs (protoveratrines, nicotine, centrally-acting cholinergic agents, ganglion-stimulating drugs). It is particularly remarkable that in pre-terminal conditions these neuropeptides and drugs have highly impressive effects on cardiocirculatory parameters at doses that are almost or actually inactive under normal conditions, and that their resuscitating effect is obtained without the need for any other supportive treatment and at dose-levels well below toxic ranges. Finally, in hemorrhage-shocked animals, the treatment with anti-analgesic neuropeptides shortly after bleeding considerably extends the time-limit for an effective and definitively curing blood reinfusion. This would be of self-evident importance in clinical practice, because an extremely simple, non-toxic first-aid treatment in the field, shortly after a massive hemorrhage, could resuscitate the patient for a period sufficient to effectively set up the most appropriate in-hospital treatment.
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Affiliation(s)
- A Bertolini
- Department of Biomedical Sciences, University of Modena, Italy
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26
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Bandoli G, Dolmella A, Gatto S, Nicolini M. X-ray studies, empirical, semi-empirical and statistical calculations on a series of thyrotropin-releasing hormone derivatives. J Mol Struct 1995. [DOI: 10.1016/0022-2860(95)08890-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Abstract
Experimental pharmacotherapy of cognitive impairment in Alzheimer's disease has seen a recent proliferation of drug trials involving a wide variety of drugs. Many of the earlier studies focused on cholinergic agents. However, subsequent advances in basic and biological sciences have broadened the scope of therapeutic strategies beyond the neurotransmitter approaches to include neurotrophic, metabolic-enhancing, membrane-modifying, and antitoxic agents, and have also provided rationale for developing antiamyloid and anti-infective therapies. For the clinician, it has not been easy to keep abreast of these developments. In this article, I present an overview of the cognition-enhancing drugs that have been used in the past, of those currently under investigation, and of new drugs and strategies that are likely to receive attention in the next few years.
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Affiliation(s)
- S V Patel
- Department of Psychiatry, University of Rochester School of Medicine and Dentistry, New York, USA
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28
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Khan A, Lai H, Ukai Y, Mirolo MH. NS-3, a TRH analog, reverses repeated ECS-induced deficits in water maze performance in the rat. Pharmacol Biochem Behav 1994; 47:477-81. [PMID: 8208765 DOI: 10.1016/0091-3057(94)90146-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rats given five consecutive daily electroconvulsive shock (ECS) treatments and trained to run in the Morris water maze, starting three days posttreatment, showed deficits in learning and memory functions. Treatment before each training session with the thyrotropin-releasing hormone (TRH) analog NS-3 [(CG-3703), (3R),(6R)-6-methyl-5-oxo-3-thiomorphorinyl-l-histidyl-l-prolinamid e tetrahydrate] reversed these behavioral deficits. The possible use of TRH and its analogs as therapeutic treatment for the cognitive dysfunctions resulting from electroconvulsive shock treatment for depression and the possible involvement of central cholinergic systems in the cognitive dysfunctions are discussed.
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Affiliation(s)
- A Khan
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle 98195
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29
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Watson CD, Hewitt MJ, Fone KC, Dickinson SL, Bennett GW. Behavioural effects of scopolamine and the TRH analogue RX77368 on radial arm maze performance in the rat. J Psychopharmacol 1994; 8:88-93. [PMID: 22298534 DOI: 10.1177/026988119400800203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Effects of repeated intracerebroventricular administration of the thyrotrophin-releasing hormone (TRH) analogue, RX77368 (3,3'-dimethyl-TRH, 2 μg, once daily), on a scopolamine-induced performance deficit in an eight-arm radial maze were evaluated in adult rats. Scopolamine (0.3 mg/kg i.p.-30 min) pre-treatment produced a significant deficit in the number of unrepeated arm entries and total arm entries and increased the percentage of incorrect arm entries and the total time on the maze, compared with saline-treated controls. Prior treatment with RX77368 (40 min before maze testing) produced a partial but significant attenuation of the scopolamine-induced performance deficit on the maze during the first five trials but RX77368 also enhanced maze performance during the same period when given alone. These results suggest that the observed scopolamine-induced performance deficit on the radial arm maze partly results from a reduction in locomotion and maze exploration rather than solely impairment of memory, and that RX77368 treatment may improve radial maze performance by increasing arousal and exploratory behaviour in rats rather than directly enhancing cognition.
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Affiliation(s)
- C D Watson
- Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham University, Nottingham NG7 2UH
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30
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Przegaliński E, Jaworska L, Budziszewska B. The role of dopamine receptors in the release of thyrotropin-releasing hormone from the rat striatum and nucleus accumbens: an in vitro study. Neuropeptides 1993; 25:277-82. [PMID: 7906871 DOI: 10.1016/0143-4179(93)90044-b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In the present study we examined the influence of dopamine (DA) stimulants: amphetamine (an agent releasing DA), apomorphine (a non-selective agonist of DA receptors), quinpirole (a selective agonist of D2 receptors) and SKF-38393 (a selective agonist of D1 receptors) on the in vitro release of thyrotropin-releasing hormone (TRH) from the rat striatal slices and nucleus accumbens fragments. It was shown that amphetamine, apomorphine and quinpirole (all those drugs added in concentrations of 10(-8)-10(-5) M), concentration-dependently increased the release of TRH, a more potent effect being observed in striatal slices. On the other hand, SKF-38393 (10(-6)-10(-5) M) was ineffective. Furthermore, the increases in the TRH release from the striatal slices, induced by 10(-5) M of amphetamine, apomorphine or quinpirole, were completely blocked by the selective D2 receptor antagonist sulpiride (10(-5) M), but not by the selective D1 receptors antagonist SCH-23390 (10(-5) M). These results indicate that stimulation of D2 receptors is responsible for the TRH release from the striatum and nucleus accumbens in vitro, and that this effect may be involved in the decrease in the peptide content in the striatum following DA stimulants, observed earlier in in vivo studies.
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Affiliation(s)
- E Przegaliński
- Institute of Pharmacology, Polish Academy of Sciences, Kraków
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31
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Mellow AM, Aronson SM, Giordani B, Berent S. A peptide enhancement strategy in Alzheimer's disease: pilot study with TRH-physostigmine infusions. Biol Psychiatry 1993; 34:271-3. [PMID: 8399826 DOI: 10.1016/0006-3223(93)90083-p] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- A M Mellow
- Department of Psychiatry, University of Michigan Medical School, Ann Arbor
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32
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Stwertka SA, Vincent GP, Gamzu ER, MacNeil DA, Verderese AG. TRH protection against memory retrieval deficits is independent of endocrine effects. Pharmacol Biochem Behav 1992; 41:145-52. [PMID: 1539064 DOI: 10.1016/0091-3057(92)90074-p] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An electrobrainshock (EBS)-induced memory retrieval deficit was produced in normal and hypophysectomized mice. In normal mice, thyrotropin-releasing hormone (TRH) (0.1 to 30 mg/kg) protected against this EBS disruption of memory after intraperitoneal but not oral (1.0 to 100 mg/kg) administration. In hypophysectomized mice, TRH (0.3 and 3.0 mg/kg) also protected against the retrieval deficit induced by EBS. The memory protection afforded by TRH was unrelated to its ability to elevate plasma levels of triiodothyronine (T3) and thyroxine (T4), nor was TRH's memory protection mediated through an anticonvulsive mechanism. These results support the notion that TRH may play an important role in memory modulation and may have therapeutic value in certain disease states in humans.
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Affiliation(s)
- S A Stwertka
- Department of Neurobiology and Obesity Research, Hoffmann-La Roche Inc., Nutley, NJ
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33
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Nie ZG, Liu ZY. Effect of injection of thyrotropin-releasing hormone into nucleus accumbens on pain discharges in nucleus parafascicularis of the thalamus in rats. JOURNAL OF TONGJI MEDICAL UNIVERSITY = TONG JI YI KE DA XUE XUE BAO 1991; 11:198-203. [PMID: 1819028 DOI: 10.1007/bf02888150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Glass microelectrode recording method was used to investigate the effect of injection of thyrotropin-releasing hormone (TRH) into nucleus accumbens, nucleus amygdalae or nucleus caudatus on unit discharges from pain-excitation neurons (PEN) in nucleus parafascicularis of the thalamus in rats. The results showed that: 1) Injection of TRH into the nucleus accumbens resulted in a significant inhibition of pain discharges from PEN in nucleus parafascicularis, while injection of TRH into nucleus amygdalae, nucleus caudatus exerted no significant effect. 2) Pretreatment with atropine abolished the above-mentioned effect of TRH. 3) Pretreatment with haloperidol also abolished the above-mentioned inhibitory effect of TRH. 4) Pretreatment with naloxone, propranolol or phentolamine did not affect the inhibitory effect of TRH. These results suggested that nucleus accumbens might be a special area in response to TRH and the effect of TRH seems to be involved in both cholinergic M-receptor and dopaminergic receptor.
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Affiliation(s)
- Z G Nie
- Department of Physiology, Tongji Medical University, Wuhan
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34
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Garbutt JC, Hicks RE, Clayton CJ, Andrews RT, Mason GA. Behavioral and endocrine interactions between thyrotropin-releasing hormone and ethanol in normal human subjects. Alcohol Clin Exp Res 1991; 15:1045-9. [PMID: 1789379 DOI: 10.1111/j.1530-0277.1991.tb05209.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Thyrotropin-releasing hormone (TRH) has been shown to antagonize the depressant effects of ethanol in animals, but conflicting findings have been reported in humans. To test whether TRH counteracts any of a variety of ethanol-sensitive behavioral measures in normal human subjects and for an effect of ethanol on TRH-induced thyrotropin (TSH) and prolactin (PRL) response, we administered TRH (500 micrograms) or placebo over 1 min intravenously, 30 min after subjects had ingested 0.8 g/kg of ethanol or a placebo drink. Blood samples for TSH and PRL were drawn prior to and 15 and 30 min after injection. Eight male subjects were studied in a balanced, crossover design with each subject receiving placebo-placebo, TRH-placebo, placebo-ethanol, and TRH-ethanol. Whereas ethanol had significant and expected effects on subjective measures, memory, disinhibition, reaction time and time perception, TRH failed to counteract any ethanol effect, except for a small effect in one memory task. Similarly, no effect of ethanol on TRH-induced TSH or PRL response was found. Though the behavioral findings could be interpreted to indicate that TRH does not alter ethanol sensitive behaviors in humans it will be necessary to utilize higher dosages of TRH and/or TRH analogues before firmly drawing this conclusion.
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Affiliation(s)
- J C Garbutt
- Center for Alcohol Studies, University of North Carolina, Chapel Hill
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35
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Przegaliński E, Jaworska L, Konarska R, Gołembiowska K. The role of dopamine in regulation of thyrotropin-releasing hormone in the striatum and nucleus accumbens of the rat. Neuropeptides 1991; 19:189-95. [PMID: 1680223 DOI: 10.1016/0143-4179(91)90118-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effect of alpha-methyl-p-tyrosine (alpha-MT), FLA-63, amphetamine, apomorphine and quinpirole on the concentration of thyrotropin-releasing hormone (TRH) in the striatum and nucleus accumbens was studied in rats. It has been found that the TRH content was increased in both those structures after alpha-MT, an inhibitor of tyrosine hydroxylase which reduced the concentration of both dopamine (DA) and noradrenaline (NA), but not after FLA-63, an inhibitor of DA-beta-hydroxylase which decreased the NA level without affecting DA. On the other hand, the indirectly acting dopaminomimetic amphetamine, the non-selective DA receptor agonist apomorphine, and the selective D2 receptor agonist quinpirole reduced the TRH level in the striatum, but not in the nucleus accumbens. Moreover, the decrease in the striatal peptide content induced by DA-mimetics was antagonized by the selective D2-receptor antagonist sulpiride, but not by the selective D1 receptor antagonist SCH 23390. The effect of amphetamine was not modified by the selective alpha 1-adrenoceptor antagonist prazosin. These results indicate that DA and D2 receptors play a significant role in the regulation of the striatal TRH.
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Affiliation(s)
- E Przegaliński
- Institute of Pharmacology, Polish Academy of Sciences, Kraków
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Ujihara H, Xie RM, Sasa M, Ishihara K, Fujita Y, Yoshimura M, Kishimoto T, Serikawa T, Yamada J, Takaori S. Inhibition by thyrotropin-releasing hormone of epileptic seizures in spontaneously epileptic rats. Eur J Pharmacol 1991; 196:15-9. [PMID: 1908388 DOI: 10.1016/0014-2999(91)90403-d] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of thyrotropin-releasing hormone (TRH) were investigated on absence-like seizures, which are characterized by the sudden appearance of 5-7 Hz spike-wave-like complexes in the cortical and hippocampal EEG, and on tonic convulsions of spontaneously epileptic rats (SER; zi/zi, tm/tm), a double mutant obtained by mating zitter homozygote (zi/zi) with tremor heterozygote rats (tm/+). TRH (5 and 10 mg/kg i.v.) inhibited the appearance of both absence-like seizures and tonic convulsions of SER without inducing obvious changes in the background EEG. The inhibitory effects were seen 5-20 min after injection of 10 mg/kg TRH and were antagonized by pretreatment with haloperidol (0.5 and 1.0/kg i.p.), although haloperidol alone did not affect the seizures. These results suggest that TRH has an antiepileptic effect in the genetically defined animal model, SER, and that the effect is mediated by the central dopaminergic system.
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Affiliation(s)
- H Ujihara
- Department of Pharmacology, Institute for Laboratory Animals, Faculty of Medicine, Kyoto University, Japan
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37
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Hutson PH, Semark JE, Middlemiss DN. The TRH analogue MK-771, increases acetylcholine release in hippocampus but not striatum of the conscious rat. Neurosci Lett 1990; 116:149-55. [PMID: 2124336 DOI: 10.1016/0304-3940(90)90401-t] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hippocampal and striatal extracellular acetylcholine levels were monitored in conscious rats using the technique of intracerebral dialysis. Scopolamine (1 mg/kg, i.p.) resulted in a marked increase of acetylcholine release in both regions whereas the thyrotropin-releasing hormone (TRH) analogue MK-771 (2.5, 5 and 10 mg/kg, i.p.) only increased acetylcholine release in the hippocampus. The relevance of the present findings in relation to the known cognitive enhancing effects of TRH analogues is discussed.
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Affiliation(s)
- P H Hutson
- Merck Sharp and Dohme Research Laboratories, Harlow, Essex, U.K
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38
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Rinaman L, Miselis RR. Thyrotropin-releasing hormone-immunoreactive nerve terminals synapse on the dendrites of gastric vagal motoneurons in the rat. J Comp Neurol 1990; 294:235-51. [PMID: 2110196 DOI: 10.1002/cne.902940208] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Thyrotropin-releasing hormone stimulates vagally mediated gastric acid secretion and motility by an undefined central mechanism in the rat. The present study sought to determine the anatomical basis for this stimulatory effect by examining the ultrastructural relationship of nerve terminals immunoreactive for thyrotropin-releasing hormone with the dendrites of gastric vagal motoneurons. A light and electron microscopic double immunostaining technique was employed using the beta subunit of unconjugated cholera toxin as a neural tracer. Cholera toxin (50 microliters, 0.25%) was injected into the ventral stomach musculature in five rats. After 72 hours' survival, animals were sacrificed by transcardiac perfusion fixation. Retrogradely transported cholera toxin was immunocytochemically localized in vagal gastric motoneurons and their dendrites in the dorsal motor nucleus of the vagus and nucleus of the solitary tract, alone or in combination with the immunocytochemical localization of thyrotropin-releasing hormone. Ultrastructural analysis of double-labeled material revealed thyrotropin-releasing hormone-immunoreactive nerve terminals making asymmetric synaptic contacts on the retrogradely labeled dendrites of vagal gastric motoneurons. Nerve terminals immunoreactive for thyrotropin-releasing hormone also made asymmetric and symmetric synaptic contacts with unlabeled dendrites of undetermined perikaryal origin. In addition, nonsynaptic varicosities immunoreactive for thyrotropin-releasing hormone were frequently observed in the vagal nuclei. The synaptic contacts between thyrotropin-releasing hormone-immunoreactive nerve terminals and vagal gastric motoneuronal dendrites provide one possible basis for the profound stimulatory effect of central thyrotropin-releasing hormone on gastric vagal motor activity.
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Affiliation(s)
- L Rinaman
- Institute of Neurological Sciences, University of Pennsylvania, Philadelphia 19104
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Yamashita K, Mori A, Otsuki S. Changes in brain thyrotropin-releasing hormone (TRH) of seizure-prone El mice. Exp Neurol 1990; 108:71-5. [PMID: 2156726 DOI: 10.1016/0014-4886(90)90009-h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We examined the anticonvulsant effects of DN-1417 an analog of the thyrotropin-releasing hormone (TRH) in seizure-prone El mice. Changes in both immunoreactive TRH (IR-TRH) and TRH receptor binding activity in discrete brain regions of El mice were also measured before and after sensitization and during the postictal period, and they were compared with those in the ddY mice. Intraperitoneal injection of DN-1417 with 150 and 450 mg/kg significantly increased the El mouse seizure threshold in a dose-dependent manner. IR-TRH in the hippocampus of El mice, which was significantly lower than in ddY mice, significantly increased after sensitization. During the postictal period, however, it slowly decreased again and then gradually recovered to the preconvulsive level without any change in TRH receptor binding. In the striatum of El mice, although TRH receptor binding was significantly higher than in ddY mice, it was not affected by sensitization. These findings indicate that the hippocampal TRH system may play an inhibitory role in El mouse seizures whereas the striatal TRH system may be important for its seizure susceptibility.
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Affiliation(s)
- K Yamashita
- Department of Neuropsychiatry, Okayama University Medical School, Japan
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40
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Okuda C, Sawa T, Harada M, Miyazaki M. Hemorrhage-induced regional brain thyrotropin-releasing hormone release in conscious rats measured by microdialysis. Life Sci 1990; 47:1997-2002. [PMID: 2125676 DOI: 10.1016/0024-3205(90)90433-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The septum, nucleus accumbens and preoptic area in the brains of conscious, freely moving rats were perfused using microdialysis probes. The TRH concentration significantly increased in the septum after withdrawal of 30% of the total blood volume but remained at constant levels in the other brain areas. Also, high potassium dose-dependently stimulated TRH release in vivo. These results suggest that blood loss stimulates septal TRH release, probably by membrane depolarization of TRH-containing nerve terminals.
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Affiliation(s)
- C Okuda
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Japan
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Lal S, Nair NP, Isaac I, Thavundayil J, Guyda H. Effect of some peptides on dopaminergic function in man. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 1990; 29:173-81. [PMID: 2113567 DOI: 10.1007/978-3-7091-9050-0_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Thyrotropin-releasing hormone (TRH) (200 micrograms iv) and 1-desamino-8-D-arginine vasopressin (DDAVP) (4 micrograms iv) antagonized the growth hormone (GH) response to apomorphine HCl (Apo) (0.5 mg sc) in 10 normal men. Apo had no effect on basal prolactin (PRL) levels but antagonized the PRL response to TRH. DDAVP plus Apo decreased PRL compared to placebo or DDAVP alone. These observations are compatible with (a) an inhibitory effect of TRH on hypothalamic and pituitary lactotrophe dopamine (DA) function (b) a facilitory effect of DDAVP on lactotrophe DA function and an inhibitory effect on hypothalamic DA function. Whether these are direct or indirect effects on DA mechanisms is unclear.
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Affiliation(s)
- S Lal
- Douglas Hospital Research Centre, Verdun, Canada
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Liu ZY, Xiao HM, Liu CJ. Effect of intracerebroventricular injection of thyrotropin-releasing hormone on the nociceptive discharges in mesencephalic reticular formation in the rat. JOURNAL OF TONGJI MEDICAL UNIVERSITY = TONG JI YI KE DA XUE XUE BAO 1989; 9:251-6. [PMID: 2517132 DOI: 10.1007/bf02909093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Extracellular recording method was used to examine the effect of thyrotropin-releasing hormone (TRH) on 71 unit discharges of pain-excited neurons (PEN) in mesencephalic reticular formation (MRF) in 58 rats. Intracerebroventricular (icv) injection of TRH (10 micrograms/10 micrograms) produced significant decrease of pain discharge rate of PEN. TRH potentiated the inhibitory effect of electroacupuncture (EA) on nociceptive discharges when application of EA at bilateral "Zusanli" was coupled with icv injection of TRH. Both of these inhibiting effects of TRH were completely offset or strikingly decreased by icv preinjection of the cholinergic M-receptor blocker atropine. The results mentioned above and the mechanism of the inhibitory effect of TRH on pain discharges were discussed in this paper.
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Butcher LL, Woolf NJ. Neurotrophic agents may exacerbate the pathologic cascade of Alzheimer's disease. Neurobiol Aging 1989; 10:557-70. [PMID: 2682328 DOI: 10.1016/0197-4580(89)90130-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The thesis is advanced that Alzheimer's disease is triggered by alterations in the regulatory mechanisms governing the patterns of cytoskeletal protein expression in structurally plastic neurons in the mature nervous system. As a consequence, polypeptide species acting to stabilize the cytoskeleton are preferentially affected, and neuronal architecture becomes increasingly determined by proteins involved in labile structural states. A cascade of interdigitating pathologies is then postulated to develop characterized by nerve terminal aberrancies, subsequent extrusion of atypical polypeptide species and their conjugates, reactive gliosis, abnormal neuronal growth, and degeneration. Within this context, growth factors promote and accelerate the pathologic cascade. Based on this model, a treatment strategy is suggested that the most effective management of Alzheimer's disease, particularly during earlier stages, is to delay its projected normal onset and to control the aberrant neuronal growth that is a hallmark of the malady.
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Affiliation(s)
- L L Butcher
- Department of Psychology, University of California, Los Angeles 90024-1563
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Muelleman RL, Gatz M, Salomone JA, Herndon B, Salzman GA. Hemodynamic and respiratory effects of thyrotropin-releasing hormone and epinephrine in anaphylactic shock. Ann Emerg Med 1989; 18:534-41. [PMID: 2497665 DOI: 10.1016/s0196-0644(89)80839-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Thyrotropin-releasing hormone (TRH) has been shown to increase mean arterial pressure during anaphylactic shock. The hemodynamic mechanism of action and the effect of TRH on the respiratory system during anaphylactic shock are not known. A rabbit model of anaphylaxis was used to determine the effect of TRH, epinephrine (EPI), and normal saline (NS) on various cardiovascular and respiratory parameters during anaphylactic shock. Anaphylactic shock was induced by antigen challenge in 31 sensitized animals. After a 25% decrease in mean arterial pressure, they were randomly treated with TRH (2 mg/kg), EPI (0.005 mg/kg), or NS (10 mL/kg). Blood was drawn at baseline and at the end of the experiment for laboratory analysis. Cardiac and respiratory parameters were monitored continuously and measured at baseline, at onset of shock (time zero), and at time intervals for 30 minutes. Animals were treated with repeated doses during the first 15 minutes as needed to maintain mean arterial pressure above shock level. Five of ten TRH-, five of 11 EPI-, and six of ten NS-treated animals survived. The TRH-treated group required fewer doses than the other groups and had increased heart rate, mean arterial pressure, peripheral vascular resistance, respiratory rate, and minute ventilation as well as decreased stroke volume index and lung compliance compared with the NS-treated group. EPI treatment resulted in increased minute ventilation and decreased pulmonary airway resistance compared with NS treatment. The EPI group also had a higher postsurvival epinephrine level than the other groups. No difference in right atrial pressure, cardiac index, acid-base status, pO2, A- a gradient, lung weight, lactate, or norepinephrine levels was found.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R L Muelleman
- Department of Emergency Health Services, Truman Medical Center, Kansas City, Missouri
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MELLOW ALANM, SUNDERLAND TREY, COHEN ROBERTM, LAWLOR BRIANA, NEWHOUSE PAULA, COHEN MARTINR, MURPHY DENNISL. A Pilot Study of Intravenous Thyrotropin-Releasing Hormone in Alzheimer's Disease. Ann N Y Acad Sci 1989. [DOI: 10.1111/j.1749-6632.1989.tb54563.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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46
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KOSKINEN LARSOWED. SECTION VIII. TRH IN SHOCK AND SPINAL TRAUMA: Effects of TRH on Blood flow and the Microcirculation. Ann N Y Acad Sci 1989. [DOI: 10.1111/j.1749-6632.1989.tb54503.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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47
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SILLS MATTHEWA, MELLOW ALANM, SUNDERLAND TREY, AULAKH CHARANJITS, NEWHOUSE PAULA, JACOBOWITZ DAVIDM. Effect of Chronic Administration of Scopolamine on Thyrotropin-Releasing Hormone (TRH)-mediated Wet-Dog Shakes and TRH Receptors as Measured by Quantitative Autoradiography. Ann N Y Acad Sci 1989. [DOI: 10.1111/j.1749-6632.1989.tb46687.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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48
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Affiliation(s)
- L O Koskinen
- Department of Physiology and Medical Biophysics, University of Uppsala, Sweden
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49
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MELLOW ALANM, SUNDERLAND TREY, COHEN ROBERTM, LAWLOR BRIANA, NEWHOUSE PAULA, COHEN MARTINR, MURPHY DENNISL. A Pilot Study of Intravenous Thyrotropin-Releasing Hormone in Alzheimer's Disease. Ann N Y Acad Sci 1989. [DOI: 10.1111/j.1749-6632.1989.tb46717.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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50
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SILLS MATTHEWA, MELLOW ALANM, SUNDERLAND TREY, AULAKH CHARANJITS, NEWHOUSE PAULA, JACOBOWITZ DAVIDM. Effect of Chronic Administration of Scopolamine on Thyrotropin-Releasing Hormone (TRH)-mediated Wet-Dog Shakes and TRH Receptors as Measured by Quantitative Autoradiography. Ann N Y Acad Sci 1989. [DOI: 10.1111/j.1749-6632.1989.tb54533.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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