Our goal was to determine whether time-dependent changes in respiratory motor output in vitro could be minimized by altering bath solution composition. Adult turtle brainstems were bathed in standard solution, nutrient-rich Dulbecco's Eagle media (100 or 25% concentration), or standard solution with phenylbiguanide (PBG, 5-HT3 agonist which increases respiratory drive). Except for a 63% frequency increase in PBG solution, hypoglossal bursts were unaltered within 100 min of observation. Respiratory activity was abolished within 7 h in 100% Dulbecco's compared with a mean of 24-31 h in other test solutions. At 12 h, burst frequency decreased faster in standard solution and 25% Dulbecco's (-0.28±0.07 and -0.13±0.05 bursts/h, respectively) compared with PBG solution (-0.09±0.04 bursts/h); amplitude declined at ∼2%/h in all solutions. The tendency for episodic discharge decreased gradually in standard solution, but was eliminated in 25% Dulbecco's and PBG solution. Certain bath solutions may minimize time-dependent frequency reductions but may also cause breathing pattern changes.
- Control of breathing, respiratory motor output
- Methods, respiratory motor output, bath solution
- Reptiles, red-eared slider turtle (Trachemys scripta)
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine