Ventilatory response to severe acute hypoxia in guinea-pigs and rats with high hemoglobin-oxygen affinity induced by cyanate.
Baseline ventilation, hemoglobin concentration (Hb) and P50 were significantly lower in guinea-pigs than in rats. Chronic sodium cyanate (NaOCN) administration did not significantly increase hemoglobin concentration in either guinea-pigs or rats. It decreased the P50 significantly less in guinea-pigs than in rats. The high Hb-O2 affinity experimentally induced did not modify the hypoxic ventilatory response (HVR) of guinea-pigs and rats. At the same level of acute hypoxia, HVR was significantly lower in NaOCN guinea-pigs than in NaOCN rats. Guinea-pigs, genotypically adapted animals to high altitude, displayed relatively minor ventilatory and Hb-O2 affinity changes to NaOCN, and a relatively minor HVR to acute hypoxia. They probably use tissue and biochemical adaptive mechanisms, in addition to their limited extracellular responses to successfully tolerate ambient hypoxia.
Departamento de Ciencias Fisiológicas, Universidad Peruana Cayetano Heredia, Lima.
M
M
Rivera
F
F
León-Velarde
L
L
Huicho
C
C
Monge
D000208:Acute Disease; D000818:Animals; D003485:Cyanates / Q000494:pharmacology*; D006168:Guinea Pigs; D006454:Hemoglobins / Q000187:drug effects / Q000378:metabolism*; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects*; D051381:Rats; D015656:Respiratory Mechanics / Q000187:drug effects*; D013045:Species Specificity
D003485:Cyanates; D006454:Hemoglobins