American alligator (Alligator mississippiensis) embryos tightly regulate intracellular pH during a severe acidosis

作者：Shartau R B; Crossley D A II; Kohl Z F; Elsey R M; Brauner C J

来源：Canadian Journal of Zoology, 2018, 96(7): 723-727.

DOI：10.1139/cjz-2017-0249

• Alligator mississippiensis
• American alligator
• acid-base physiology
• development
• reptile
• preferential pH(i )regulation
• hypercarbia
• amniotes

Crocodilian nests naturally experience high CO2 (hypercarbia), which leads to increased blood P-CO2 and reduced blood pH (pH(i)) in embryos; their response to acid-base challenges is not known. During acute hypercarbia, snapping turtle embryos preferentially regulate tissue pH (pH(i)) against pH(e) reductions. This is proposed to be associated with CO2 tolerance in reptilian embryos and is not found in adults. In the present study, we investigated pH regulation in American alligator (Alligator mississippiensis (Daudin, 1802)) embryos exposed to 1 h of hypercarbia hypoxia (13 kPa P-CO2 , 9 kPa P-O2). Hypercarbia hypoxia reduced pH(e) by 0.42 pH unit, while heart and brain pH(i) increased, with no change in the pH(i) of other tissues. The results indicate that American alligator embryos preferentially regulate pH(i), similar to snapping turtle embryos, which represents a markedly different strategy of acid-base regulation than what is observed in adult reptiles. These findings suggest that preferential pH, regulation may be a strategy of acid-base regulation used by embryonic reptiles.

• 出版日期2018-7