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Maturation Influences effects of long‐term facilitation induced changes in inspiratory network complexity in urethane‐anesthetized neonatal rats
Author(s) -
Reid Inefta M,
Solomon Irene C
Publication year - 2008
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.22.1_supplement.755.7
Subject(s) - respiratory system , approximate entropy , respiration , anesthesia , medicine , control of respiration , facilitation , cardiology , biology , neuroscience , psychology , anatomy , pattern recognition (psychology) , cognitive psychology
Long‐term facilitation (LTF) is a form of respiratory plasticity, which is expressed as a persistent increase in inspiratory motor output following intermittent, but not continuous, hypoxia. Although numerous studies have examined timing and magnitude changes in respiratory LTF, changes in inspiratory network complexity (quantified by approximate entropy ApEn analysis) in neonatal Sprague‐Dawley rats have only begun to be explored. Here we extend earlier analyses by examining ApEn of diaphragm EMG bursts recorded from spontaneously breathing urethane‐anesthetized neonatal rats (P12–21 n=18) before and at 5‐min intervals for at least 60‐min following three 5‐min episodes of hypoxia (8% O 2 ); all rats were continuously supplied with 4% CO 2 to minimize hypoxic respiratory depression. Under these conditions, respiratory LTF was seen mainly as an increase in burst frequency although in some cases an increase in amplitude was observed. During LTF, ApEn values increased from 0.37±0.04 to 0.42±0.02 (P=0.004) P12–P13 rats(n=7) and from 0.40±0.03 to 0.43±0.03 (P=0.04) in P21 rats(n=3), with the peak response seen at ≥50 min. In contrast, ApEn values decreased from 0.40±0.03 to 0.36±0.03 (P=0.007) in P14–P18 rats(n=8), with the peak response seen at ≤45 min. These data show that inspiratory network complexity is modified during LTF, and that the stage of development affects LTF‐related network reconfiguration.