Biomaterial Database

Ventilatory and metabolic responses to cold and CO-induced hypoxia in awake rats. 1994

H Gautier, and M Bonora

Faculté de Médecine Saint-Antoine, Paris, France.

Experiments were carried out in awake rats to compare the effects of ambient and CO-induced hypoxia on thermoregulation and ventilatory control. Measurements of metabolic rate (VO2), ventilation (V), shivering (EMG) and colonic temperature (Tc) were made at fixed ambient temperature (Ta) of 25, 15 and 5 degrees C. Animals were exposed to ambient hypoxia (FIO2 of 21, 17, 14, 12 and 10%) or to CO hypoxia (FICO of 0.03% in air). The results show that: (1) Both ambient and CO-induced hypoxia provoked decreases in VO2 and Tc which were more marked at low Ta values; non-shivering thermogenesis was depressed with both types of hypoxia, whereas shivering was depressed only with ambient hypoxia; (2) Ventilatory response to ambient hypoxia was blunted at low Ta values and CO-induced hypoxia did not affect ventilation. It is concluded that: (1) hypoxia affects markedly the control of Tc by altering thermogenesis: inhibition of non-shivering thermogenesis seems to result from a decrease in CaO2 whereas inhibition of shivering seems to result from a decrease in PaO2; (2) during hypoxia, ventilation is controlled by the opposite stimulation from chemoreceptors and inhibition from hypometabolism. However, as revealed by CO-induced hypoxia, another stimulatory factor may also interact with the control of breathing.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D001831	Body Temperature	The measure of the level of heat of a human or animal.	Organ Temperature,Body Temperatures,Organ Temperatures,Temperature, Body,Temperature, Organ,Temperatures, Body,Temperatures, Organ
D002248	Carbon Monoxide	Carbon monoxide (CO). A poisonous colorless, odorless, tasteless gas. It combines with hemoglobin to form carboxyhemoglobin, which has no oxygen carrying capacity. The resultant oxygen deprivation causes headache, dizziness, decreased pulse and respiratory rates, unconsciousness, and death. (From Merck Index, 11th ed)	Monoxide, Carbon
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D003106	Colon	The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.	Appendix Epiploica,Taenia Coli,Omental Appendices,Omental Appendix,Appendices, Omental,Appendix, Omental
D005740	Gases	The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000860	Hypoxia	Sub-optimal OXYGEN levels in the ambient air of living organisms.	Anoxia,Oxygen Deficiency,Anoxemia,Deficiency, Oxygen,Hypoxemia,Deficiencies, Oxygen,Oxygen Deficiencies