TY - JOUR
T1 - Development of avian intrapulmonary chemoreceptors
AU - Pilarski, Jason Q.
AU - Hempleman, Steven C.
N1 - Funding Information:
The authors thank Delbert Kilgore Jr. for significant assistance and helpful discussions during all phases of this study. We would also like to thank Cinnamon Pace for critical reading of this manuscript, and Jenna Monroy for insightful conversations about neural plasticity. This project was supported by the U.S. National Science Foundation Grant #IBN-0217815.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/8/1
Y1 - 2007/8/1
N2 - Although avian intrapulmonary chemoreceptors (IPC) have been studied extensively in adults, the maturation of IPC CO2 sensitivity during development is completely unknown. To begin investigating IPC development we asked two fundamental questions: (1) Are IPC capable of sensing CO2 during early development, and, if so, how early? And, (2) does IPC CO2 sensitivity during early development exhibit postnatal maturation compared to IPC discharge characteristics in adult ducks? We addressed these questions by recording from single IPC Anas platyrhynchos ducklings beginning approximately 6 h prior to internal pipping through 4 days of postnatal development. We then compared mean IPC discharge characteristics during early development with mean IPC activity from adult ducks greater than 12 weeks old. In total, we recorded 28 individual IPC from 5 ducklings and 12 adult ducks. Results show that IPC were capable of responding to rapid step changes in CO2 before hatching occurred, during the paranatal developmental period. We also found that mean IPC activity during early development had increased peak discharge frequencies, greater spike frequency adaptation, and less tonic CO2 sensitivity when compared to adults (P ≤ 0.05). These results suggest that during early development phasic IPC CO2 sensitivity is fully developed, yet tonic IPC CO2 sensitivity exhibits postnatal maturation possibly associated with hatching. These results also suggest that the mechanisms that underlie phasic and tonic IPC action potential discharge, and therefore the degree of partial spike frequency adaptation, may be independent processes with different developmental trajectories.
AB - Although avian intrapulmonary chemoreceptors (IPC) have been studied extensively in adults, the maturation of IPC CO2 sensitivity during development is completely unknown. To begin investigating IPC development we asked two fundamental questions: (1) Are IPC capable of sensing CO2 during early development, and, if so, how early? And, (2) does IPC CO2 sensitivity during early development exhibit postnatal maturation compared to IPC discharge characteristics in adult ducks? We addressed these questions by recording from single IPC Anas platyrhynchos ducklings beginning approximately 6 h prior to internal pipping through 4 days of postnatal development. We then compared mean IPC discharge characteristics during early development with mean IPC activity from adult ducks greater than 12 weeks old. In total, we recorded 28 individual IPC from 5 ducklings and 12 adult ducks. Results show that IPC were capable of responding to rapid step changes in CO2 before hatching occurred, during the paranatal developmental period. We also found that mean IPC activity during early development had increased peak discharge frequencies, greater spike frequency adaptation, and less tonic CO2 sensitivity when compared to adults (P ≤ 0.05). These results suggest that during early development phasic IPC CO2 sensitivity is fully developed, yet tonic IPC CO2 sensitivity exhibits postnatal maturation possibly associated with hatching. These results also suggest that the mechanisms that underlie phasic and tonic IPC action potential discharge, and therefore the degree of partial spike frequency adaptation, may be independent processes with different developmental trajectories.
KW - Carbon dioxide
KW - Control of breathing
KW - Development
KW - Hatching
KW - IPC
KW - Intrapulmonary chemoreceptors
KW - Maturation
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U2 - 10.1016/j.resp.2007.01.015
DO - 10.1016/j.resp.2007.01.015
M3 - Article
C2 - 17331814
AN - SCOPUS:34249050192
SN - 1569-9048
VL - 157
SP - 393
EP - 402
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 2-3
ER -