title: Effects of fasting on hypoxic ventilatory responses and the contribution of histamine H1 receptors in mice.
abstract: We tested the hypothesis that fasting affects hypoxic ventilatory responses through metabolic changes via histamine H1 receptors. Wild-type (WT) and histamine H1 receptor knockout (H1RKO) mice were studied in fed and fasted states. In the fed WT, hypoxic-gas exposure elicited an increase and a subsequent decline in ventilation (hypoxic ventilatory decline or HVD). HVD was influenced by fasting in breathing pattern with metabolic rate. Fasting elicited hypoglycemia, a drop in R, and increases in free fatty acid and ketone bodies in the serum. In H1RKO, HVD was blunted in the fed state, but it appeared in the fasted state. There was a minimal drop in R following fasting and a low triglyceride concentration. Thus, fasting affects HVD through a change in energy mobilization from glucose to lipid metabolism. Histamine H1 receptors are involved in HVD during fed and fasted states, resulting in adaptation to the environmental conditions.
authors.affiliation: 2nd Department of Physiology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan.
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Ohshima
authors.forename: Michiko
authors.initials: M
authors.lastname: Iwase
authors.forename: Masahiko
authors.initials: M
authors.lastname: Izumizaki
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nakayama
authors.forename: Ichiei
authors.initials: I
authors.lastname: Narita
authors.forename: Ikuo
authors.initials: I
authors.lastname: Homma
mesh_terms: D000818:Animals; D001481:Basal Metabolism; D001786:Blood Glucose / Q000378:metabolism; D004734:Energy Metabolism; D005215:Fasting / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood / Q000378:metabolism; D007003:Hypoglycemia / Q000503:physiopathology; D000860:Hypoxia / Q000378:metabolism*; D007657:Ketone Bodies / Q000097:blood / Q000378:metabolism; D019344:Lactic Acid / Q000097:blood; D008049:Lipase / Q000378:metabolism; D008055:Lipids / Q000097:blood; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D012123:Pulmonary Ventilation / Q000502:physiology*; D011969:Receptors, Histamine H1 / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007657:Ketone Bodies; D008055:Lipids; D011969:Receptors, Histamine H1; D019344:Lactic Acid; D008049:Lipase