Aerobic scope falls to nil at Pcrit and anaerobic ATP production increases below Pcrit in the tidepool sculpin, Oligocottus maculosus.
Biol Lett
; 18(12): 20220342, 2022 12.
Article
en En
| MEDLINE
| ID: mdl-36475421
The critical oxygen tension of whole-animal oxygen uptake rate, or Pcrit, has historically been defined as the oxygen partial pressure (PO2) at which aerobic scope falls to zero and further declines in PO2 require substrate-level phosphorylation to meet shortfalls in aerobic ATP production, thereby time-limiting survival. Despite the inclusion of aerobic scope and anaerobic ATP production in the definition, little effort has been made to verify that Pcrit measurements, the vast majority of which are obtained using respirometry in resting animals, actually reflect the predictions of zero aerobic scope and a transition to increasing reliance on anaerobic ATP production. To test these predictions, we compared aerobic scope and levels of whole-body lactate at oxygen partial pressures (PO2s) bracketing Pcrit obtained in resting fish during progressive hypoxia in the tidepool sculpin, Oligocottus maculosus. We found that aerobic scope falls to zero at Pcrit and, in resting fish exposed to PO2s < Pcrit, whole-body lactate accumulated pointing to an increased reliance on anaerobic ATP production. These results support the interpretation of Pcrit as a key oxygen threshold at which aerobic scope falls to nil and, below Pcrit, survival is time-limited based on anaerobic metabolic capacity.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxígeno
/
Adenosina Trifosfato
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Biol Lett
Asunto de la revista:
BIOLOGIA
Año:
2022
Tipo del documento:
Article
Pais de publicación:
Reino Unido