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Novel Insights into Anatomical and Functional Roles of Nucleus Retroambiguus in Respiratory Function
Author(s) -
Jones Sarah,
Stanić Davor,
Dutschmann Mathias
Publication year - 2015
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.29.1_supplement.1034.3
Subject(s) - biotinylated dextran amine , anterograde tracing , brainstem , neuroscience , respiratory system , spinal cord , anatomy , biology , population , nucleus , chemistry , medicine , environmental health
Purpose The study aims to elucidate the role and contribution of nucleus retroambiguus (NRA) in generating or modulating the respiratory central pattern generator (rCPG). Previously we identified a putative rhythmogenic area 1.5 mm caudal to obex in the rat in‐situ perfused brainstem‐spinal cord preparation. Histological analysis indicated the putative rhythmogenic cell population resides at the level of the pyramidal decussation, therefore likely to overlap with the NRA. We investigated possible involvement of NRA in rhythmogenesis anatomically and functionally. Methods Anatomical tracing: Anterograde neuronal tracer, biotinylated dextran amine, was injected into the NRA. Respiratory areas which contained labelled terminal fields received the retrograde tracer Fast Blue in subsequent experiments. Functional testing: Glutamate microinjections were made in a grid formation across the NRA region in the rat in‐situ perfused brainstem spinal cord preparation; with whole nerve recordings taken from phrenic and vagus nerves. Results Anterograde and retrograde tracing revealed anatomical connectivity between the NRA and respiratory nuclei, including the pre‐Bötzinger complex, parafacial respiratory group and Kölliker Fuse nucleus. Glutamate mapping in‐situ revealed two distinct responses to pharmacological stimulation. A tachypneic response was seen predominantly overlapping the NRA whilst a breath hold response was seen more frequently in the periphery, dorsal and lateral to the NRA. Conclusion Anatomical evidence shows that NRA can drive respiratory modulation via ascending projections to the rCPG. Therefore the NRA is not just a bulbospinal relay, but rather an integral part of the rCPG. Funding: Melbourne University