2-Deoxy-d-glucose-induced hypothermia in anesthetized rats: Lack of forebrain contribution and critical involvement of the rostral raphe/parapyramidal regions of the medulla oblongata
| Autor: | Toshimasa Osaka |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Male
Tail medicine.medical_specialty GABA Agents Hypothermia Deoxyglucose Biology Urethane Midbrain Prosencephalon Internal medicine medicine Animals Rats Wistar gamma-Aminobutyric Acid Decerebrate State Raphe General Neuroscience Thermogenesis Thermoregulation Receptors GABA-A Respiration Artificial Endocrinology Chloralose nervous system Regional Blood Flow Models Animal Forebrain Neuromuscular Blockade Medulla oblongata Raphe Nuclei GABAergic Brainstem medicine.symptom Anesthetics Intravenous |
| Zdroj: | Brain Research Bulletin. 116:73-80 |
| ISSN: | 0361-9230 |
| DOI: | 10.1016/j.brainresbull.2015.06.008 |
| Popis: | Systemic or central administration of 2-deoxy- d -glucose (2DG), a competitive inhibitor of glucose utilization, induces hypothermia in awake animals and humans. This response is mediated by the central nervous system, though the neural mechanism involved is largely unknown. In this study, I examined possible involvement of the forebrain, which contains the hypothalamic thermoregulatory center, and the medullary rostral raphe/parapyramidal regions (rRPa/PPy), which mediate hypoxia-induced heat-loss responses, in 2DG-induced hypothermia in urethane–chloralose-anesthetized, neuromuscularly blocked, artificially ventilated rats. The intravenous injection of 2DG (250 mg kg −1 ) elicited an increase in tail skin temperature and decreases in body core temperature and the respiratory exchange ratio, though it did not induce any significant change in the metabolic rate. These results indicate that the hypothermic response was caused by an increase in heat loss, but not by a decrease in heat production and that it was accompanied by a decrease in carbohydrate utilization and/or an increase in lipid utilization as energy substrates. Complete surgical transection of the brainstem between the hypothalamus and the midbrain had no effect on the 2DG-induced hypothermic responses, suggesting that the hindbrain, but not the forebrain, was sufficient for the responses. However, pretreatment of the rRPa/PPy with the GABA A receptor blocker bicuculline methiodide, but not with vehicle saline, greatly attenuated the 2DG-induced responses, suggesting that the 2DG-induced hypothermia was mediated, at least in part, by GABAergic neurons in the hindbrain and activation of GABA A receptors on cutaneous sympathetic premotor neurons in the rRPa/PPy. |
| Databáze: | OpenAIRE |
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