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Baig MS, Joseph V. Age specific effect of MK-801 on hypoxic body temperature regulation in rats. Respir Physiol Neurobiol 2007; 160:181-6. [PMID: 17964229 DOI: 10.1016/j.resp.2007.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 09/14/2007] [Accepted: 09/17/2007] [Indexed: 10/22/2022]
Abstract
Hypoxic exposure produces a consistent decrease of rectal temperature (Tb), which is recognized as a potent protective response. While some of the neural mechanisms underlying this response have recently been described, it remains poorly known how these mechanisms evolve during post-natal development. We recently reported that in rat pups NMDA glutamate receptor limits Tb drop upon hypoxic exposure, an effect that has not been reported by others in adult rats. Accordingly, we tested the hypothesis that the implication of NMDA receptors on temperature control during hypoxic exposure evolves during development. To this aim, we evaluated the hypoxic (30 min - 12% O(2)) responses of Tb, metabolic rate, and ventilation in rats after injection of vehicle, or the NMDA receptor antagonist MK-801, at different ages (post-natal days 4, 10, 20 and 2-3 month-old - P4, P10, P20 and P60). MK-801 amplified the magnitude of the hypoxic-induced Tb drop in P4, P10 and P20 rats, but this effect was not apparent in adults. In P20 rats MK-801 tripled the hypoxic induced Tb drop, which was 0.5 degrees C in control and 1.4 degrees C in treated rats (p<0.0001). This effect was specific to temperature regulation, and was not accompanied by similar changes of other recorded parameters. MK-801 induced a significant decrease of the hypoxic ventilatory response in adults only. We conclude that NMDA glutamate receptor acts as a counter-regulatory factor that limits the hypoxic-induced drop of rectal temperature during post-natal development in rats.
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Affiliation(s)
- Mirza Shafiulla Baig
- Department of Pediatrics, Laval University, Centre de Recherche CHUQ, Hôpital St-François d'Assise, Local D0-711, 10 Rue de l'Espinay, Quebec, QC G1L 3L5, Canada
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Baig MS, Joseph V. Activation of NMDA receptors prevents excessive metabolic decrease in hypoxic rat pups. Respir Physiol Neurobiol 2006; 152:61-71. [PMID: 16040283 DOI: 10.1016/j.resp.2005.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 06/17/2005] [Accepted: 06/18/2005] [Indexed: 11/29/2022]
Abstract
We tested the hypothesis that glutamate NMDA receptors may help maintain metabolic rate and body temperature during acute or chronic hypoxic exposure in newborn rats. We recorded ventilation, metabolism ((.)V(O(2)) -- ((.)V(CO(2)) and rectal temperature, under normoxia, acute hypoxia (30 min -- 12% O(2)), or following 10 days of chronic hypoxia, in 10 days old male and female rats, receiving saline i.p. injection or the NMDA receptor antagonist MK-801. Acute hypoxia decreased rectal temperature and metabolism, and increased ventilation, and (.)V(E)/((.)V(O(2) and (.)V(E)/((.)V(CO(2) to the same extent in males and females. MK-801 injection amplified the metabolic decrease under acute (in males and females) and chronic (in males) hypoxia, prevented the increase of minute ventilation, while (.)V(E)/((.)V(O(2) or (.)V(E)/((.)V(CO(2)remained constant. Hence, NMDA glutamate receptors help to maintain metabolic rate, minute ventilation and body temperature at a determined level in acute (males and females) and chronic hypoxia (males only).
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Affiliation(s)
- Mirza Shafiulla Baig
- Department of Pediatrics, Laval University, Centre de Recherche (D0-711), Hôpital St-François d'Assise, 10 rue de l'Espinay, Que. (QC), Canada G1L 3L5
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Canini F, Bourdon L, Bittel J. Effect of ambient temperatures ranging from cold to heat on thermoregulation in conscious MK801-treated rats. Can J Physiol Pharmacol 2003; 81:959-65. [PMID: 14608413 DOI: 10.1139/y03-098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The glutamate NMDA receptor has been suggested to be involved in thermoregulation. To further analyse its role, the thermoregulatory responses of rats treated with 0.5 mg·kg1 of dizocilpine (MK801) were compared with those of control rats treated only with the same volume of saline during a 180-min exposure at one of the six different ambient temperatures, ranging from cold to heat. Colonic temperature (Tco) and tail skin temperature (Ttail) were measured throughout using CuCt thermocouples. In the cold (2.4 and 12.3 °C), Tco decreased either sharply (MK801) or progressively (saline), reaching the same final value (2.4 °C) or a lower value in the MK801-treated rats (12.3 °C). At the same time, Ttail decreased in both groups. In the cool environment (20.7 °C), Tco and Ttail decreased in both groups, with lower final values in MK801-treated rats. At thermoneutrality (28.8 °C), the MK801-induced hyperthermia remained steady, while Ttail increased in both groups. In the heat (34.6 and 36.2 °C), Tco and Ttail increased in both groups, with higher final values in MK801-treated rats. Moreover, at 36.2 °C, only MK801-treated rats exhibited heatstroke. It is thus suggested that MK801-induced inhibition of NMDA receptors impairs thermoregulation, especially in the heat.Key words: thermoregulation, NMDA receptor, MK801, poikilothermia, rat.
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Affiliation(s)
- F Canini
- Centre de rechercres du Service de santé des armées, Département des facteurs humains, La Tronche, France.
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Canini F, Bréjot T, d'Aléo P, Mercier S, Bourdon L. NMDA receptors are involved in dithiothreitol-induced hypothermia. Eur J Pharmacol 2001; 426:179-83. [PMID: 11527542 DOI: 10.1016/s0014-2999(01)01219-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Sulfhydryl-reducing agents, such as dithiothreitol, modulate glutamate N-methyl-D-aspartate (NMDA) receptors. Since these receptors are involved in thermoregulatory processes, we studied the effects of their positive modulation, through a dithiothreitol-induced reduction of the receptor redox site, on thermoregulation in rats maintained at an ambient temperature of 20-22 degrees C. Given intraperitoneally at the dose of 25 and 50 mg x kg(-1), dithiothreitol induced dose-dependent hypothermia. The prior administration of 0.5 mg x kg(-1) of (+/-)-dizocilpine maleate (MK801), a non-competitive glutamate NMDA receptor antagonist, blocked most of the dithiothreitol-induced hypothermia. MK801 given alone was followed by slight transient hyperthermia. This confirms the involvement of NMDA receptors in thermoregulation and suggests that they might be under redox modulation.
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Affiliation(s)
- F Canini
- Centre de Recherches du Service de Santé des Armées, Département des Facteurs Humains, 24 Avenue des Maquis du Grésivaudan, BP 87, F-38702 La Tronche Cedex, France.
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5
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Abstract
Experimental and clinical damage to the brain leads to rapid upregulation of an array of cytokines predominantly by glia. These cytokines may exert neurotoxic or neuroprotective actions. This paper will focus on the pro-inflammatory cytokine interleukin-1 (IL-1), which participates in diverse forms of brain damage including ischemia, brain trauma, and excitotoxic injury. Administration of low doses of IL-1 markedly exacerbates these forms of brain damage, whereas blocking IL-1 release or actions reduces neuronal death. IL-1 receptor antagonist (IL-1ra) is also upregulated by brain damage (mainly by neurons) and acts as an endogenous inhibitor of neurodegeneration, presumably by blocking IL-1 actions on its receptor. We have studied the actions of both IL-1 and IL-1ra in experimental models of ischemic and neurotoxic injury in rats, and have found site-specific effects within the striatum. On the basis of this and further work, we propose that IL-1 can exacerbate cell death in these conditions by modifying polysynaptic anterograde pathways leading from the striatum to the cortex. The precise nature of these pathways remains undetermined, as do the underlying mechanisms by which IL-1 can exert its effects, but appear to involve induction of IL-1 in specific brain regions and activation of cortical glutamatergic pathways.
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Affiliation(s)
- S M Allan
- School of Biological Sciences, 1.124 Stopford Building, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom.
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Allan SM, Parker LC, Collins B, Davies R, Luheshi GN, Rothwell NJ. Cortical cell death induced by IL-1 is mediated via actions in the hypothalamus of the rat. Proc Natl Acad Sci U S A 2000; 97:5580-5. [PMID: 10779559 PMCID: PMC25871 DOI: 10.1073/pnas.090464197] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The cytokine IL-1 mediates diverse forms of neurodegeneration, but its mechanism of action is unknown. We have demonstrated previously that exogenous and endogenous IL-1 acts specifically in the rat striatum to dramatically enhance ischemic and excitotoxic brain damage and cause extensive cortical injury. Here we tested the hypothesis that this distant effect of IL-1 is mediated through polysynaptic striatal outputs to the cortex via the hypothalamus. We show that IL-1beta injected into the rat striatum with the excitotoxin alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (S-AMPA) caused increased expression of IL-1beta (mRNA and protein) mainly in the cortex where maximum injury occurs. Marked increases in IL-1beta mRNA and protein were also observed in the hypothalamus. S-AMPA, injected alone into the striatum, caused only localized damage, but administration of IL-1beta into either the striatum or the lateral hypothalamus immediately after striatal S-AMPA resulted in widespread cell loss throughout the ipsilateral cortex. Finally we showed that the cortical cell death produced by striatal coinjection of S-AMPA and IL-1beta was significantly reduced by administration of the IL-1 receptor antagonist into the lateral hypothalamus. These data suggest that IL-1beta can act in the hypothalamus to modify cell viability in the cortex. We conclude that IL-1-dependent pathways project from the striatum to the cortex via the hypothalamus and lead to cortical injury, and that these may contribute to a number of human neurological conditions including stroke and head trauma.
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Affiliation(s)
- S M Allan
- School of Biological Sciences, 1.124 Stopford Building, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
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Grundy RI, Rothwell NJ, Allan SM. Dissociation between the effects of interleukin-1 on excitotoxic brain damage and body temperature in the rat. Brain Res 1999; 830:32-7. [PMID: 10350557 DOI: 10.1016/s0006-8993(99)01377-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The cytokine interleukin-1beta (IL-1beta) mediates and exacerbates excitotoxic brain damage in the rat striatum. Co-injection of the selective glutamate receptor agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (S-AMPA) with human recombinant IL-1beta (hrIL-1beta) in the striatum of rats results in both local (striatal) damage and extensive, distant neuronal death in the cortex. The objective of the present study was to investigate the mechanisms underlying IL-1beta actions on excitotoxic damage, and to determine whether this effect of IL-1beta, a potent pyrogen, is due to modification of body temperature. Striatal infusion of S-AMPA (7.5 nmol) in anaesthetised rats produced localised striatal damage. Intrastriatal co-infusion of hrIL-1beta (10 ng) with S-AMPA caused similar striatal damage, but also produced extensive cortical damage, together with a modest increase in body temperature (0.9 degrees C) compared to rats infused with S-AMPA alone. Infusion of S-AMPA into the striatum, together with intracerebroventricular (i.c.v.) injection of hrIL-1beta, produced a similar rise in temperature to striatal co-infusion of S-AMPA and hrIL-1beta, but resulted in only local (striatal) neuronal damage, that was similar to that caused by striatal infusion of S-AMPA alone. These data suggest that the effects of IL-1beta on AMPA-receptor mediated neuronal damage in the striatum can be dissociated from its pyrogenic effects on body temperature.
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Affiliation(s)
- R I Grundy
- School of Biological Sciences, 1.124 Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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Yanase T, Hara S, Mukai T, Kuriiwa F, Iwata N, Kano S, Endo T. Characterization of temperature rise of the brain and the rectum following intracerebroventricular administration of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate and kainate in rats. Brain Res 1998; 798:304-10. [PMID: 9666153 DOI: 10.1016/s0006-8993(98)00453-3] [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: 02/08/2023]
Abstract
Intracerebroventricular administration of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) or kainate caused a rise of the temperature of the brain and the rectum in urethane-anesthetized rats. An AMPA-kainate receptor antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX), significantly suppressed the AMPA- and kainate-induced rises of brain and rectal temperatures. An N-methyl-d-aspartate receptor antagonist, MK-801, also suppressed the rises of the brain and rectal temperatures induced by AMPA or kainate, but the profiles of the suppressive effects of MK-801 were different between rats treated with AMPA and kainate. An antipyretic agent, indomethacin, completely suppressed the AMPA-induced rises of brain and rectal temperatures. Although indomethacin completely suppressed the kainate-induced rise of the rectal temperature as well, the brain temperature was still raised. These findings suggest that distinct mechanisms may be involved in the temperature rise of the brain and the rectum mediated through AMPA and kainate receptor stimulation.
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Affiliation(s)
- T Yanase
- Department of Forensic Medicine, Tokyo Medical College, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan
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Hara S, Mukai T, Kuriiwa F, Iwata N, Yanase T, Kano S, Endo T. Distinct effects of MK-801 and (+/-)-2-amino-5-phosphonopentanoic acid on N-methyl-D-aspartate-induced rise of brain temperature in rats. Life Sci 1997; 61:PL 289-94. [PMID: 9366516 DOI: 10.1016/s0024-3205(97)00867-9] [Citation(s) in RCA: 7] [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
Intracerebroventricular (i.c.v.) administration of N-methyl-D-aspartate (NMDA) caused a biphasic rise of brain temperature, namely, a rapid, early rise and a larger, late rise, in urethane-anesthetized rats. I.c.v. pretreatment with a noncompetitive NMDA receptor antagonist, MK-801, attenuated the late rise of the brain temperature, but had no effect on the early rise, whereas i.c.v. pretreatment with a competitive NMDA receptor antagonist, (+/-)-2-amino-5-phosphonopentanoic acid (AP-5), attenuated both rises. AP-5 per se caused a rise in brain temperature without any rise of rectal temperature, whereas MK-801 per se caused no significant change of the brain or rectal temperature. This rise by AP-5 was suppressed by MK-801, suggesting an agonistic effect of AP-5 on NMDA receptors in rat brain in vivo.
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Affiliation(s)
- S Hara
- Department of Forensic Medicine, Tokyo Medical College, Japan.
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