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Developmental changes in inspiratory network complexity and burst timing during gasping in urethane‐anesthetized rat in vivo
Author(s) -
Yu Hui Jing,
Chen Xinnian,
Solomon Irene C
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a561
Subject(s) - apnea , basal (medicine) , approximate entropy , in vivo , anesthesia , respiration , medicine , biology , psychology , anatomy , microbiology and biotechnology , insulin , pattern recognition (psychology) , cognitive psychology
We have recently begun to examine the influence of maturational changes on inspiratory burst complexity and timing in vivo ; however, our initial studies focused only on eupneic (basal) inspiratory bursts. Thus, the influence of maturation on these parameters during gasping remains to be identified. Therefore, we computed the approximate entropy (ApEn, as an index of network complexity) and burst duration (T I ) of gasps recorded from the diaphragm ( i.e ., EMG activity) in spontaneously breathing urethane‐anesthetized neonatal rats. Decreasing inspired O 2 from 40% to 0% elicited gasping in 33 of 36 P0‐10 rats and 6 of 30 P11‐22 rats, with onset latencies (from apnea) of ~3 and 1.8 min, respectively (P<0.05); no gasps were observed in P15‐18 rats (n=11). Comparison of basal bursts to gasps showed that ApEn was reduced from 0.31±0.01 to 0.25±0.01 (P<0.001) and T I was reduced from 105±5 to 69±5 ms (P<0.001). Evaluation of the magnitude of the ApEn and T I decreases between P1‐10 (n=15) and P11‐21 (n=6) rats revealed that the ApEn decrease was similar for both groups (16±4% and 21±10%; P=0.6) while that of T I was markedly different (22±7% and 54±8%; P=0.03). Our findings demonstrate that young neonatal rats exhibit a higher likelihood of gasping in response to severe hypoxia, and that changes in inspiratory network complexity, but not burst timing, during gasping are similar with maturation. We suggest that these changes reflect reconfiguration of the central respiratory network associated with both gasping and development. Supported by NS045321 and NS049310