Activation of NMDA receptors prevents excessive metabolic decrease in hypoxic rat pups.
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).
Baig
Mirza Shafiulla
MS
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.
Joseph
Vincent
V
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D000860:Hypoxia / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D008660:Metabolism / Q000187:drug effects / Q000502:physiology*; D011247:Pregnancy; D011659:Pulmonary Gas Exchange / Q000187:drug effects / Q000502:physiology; D012123:Pulmonary Ventilation / Q000187:drug effects / Q000502:physiology; D011897:Random Allocation; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*; D012737:Sex Factors; D013997:Time Factors
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate