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Role of GABA and Glycine in the Development of Respiratory Rhythmogenesis in the Embryonic Zebra Finch
Author(s) -
Stein Paxton S.,
Pickett Kaci L.,
VincenBrown Michael A.,
Pilarski Jason Q.
Publication year - 2016
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.30.1_supplement.987.2
Subject(s) - strychnine , zebra finch , neuroscience , glycine receptor , brainstem , biology , glycine , 4 aminopyridine , endocrinology , biochemistry , amino acid , potassium channel
Primordial breathing‐related neural networks in the avian brainstem become active during the early embryonic period (day 4) but are not functional until embryonic day 12 (E12) when internal pipping occurs. At this time, birds, unlike mammals, employ active inspiration and expiration during each ventilatory cycle, but the extent to which GABA and glycine contribute to the cycle is still unknown. We aim to test the role of chloride‐mediated neurotransmission (NT) throughout this respiratory‐related development in ovo using the altricial Zebra Finch ( T. guttata ), which allows for unimpeded access to neural circuits during the entire embryonic period. We measured spontaneous rhythmic activity from cranial nerve IX (glossopharyngeal) between E4 and hatching (E14) in the presence and absence of the GABA/glycine antagonists bicuculline and strychnine using the in vitro brainstem spinal cord preparation. Results indicate that GABA/glycine NT is excitatory from E4 through E11. However, near E11, blocking GABA/glycine NT had little effect on the frequency of cranial nerve IX discharge but significantly increased burst area, which suggests an increase in phasic excitation of the glossopharyngeal motor nucleus. Support or Funding Information IDeA Network of Biomedical Research Excellence (INBRE), NIH grant P20 PR016454 NIH Academic Research Enhancement Award (AREA) Program, 1R15NS087521‐01A1