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Testing the role of preBötzinger Complex somatostatin neurons in respiratory and vocal behaviors
Author(s) -
Tupal Srinivasan,
Rieger Michael A.,
Ling GuangYi,
Park Thomas J.,
Dougherty Joseph D.,
Goodchild Ann K.,
Gray Paul A.
Publication year - 2014
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12669
Subject(s) - glutamatergic , biology , respiratory system , somatostatin , neuroscience , glutamate receptor , brainstem , population , medicine , endocrinology , receptor , anatomy , biochemistry , environmental health
Identifying neurons essential for the generation of breathing and related behaviors such as vocalisation is an important question for human health. The targeted loss of preBötzinger Complex (preBötC) glutamatergic neurons, including those that express high levels of somatostatin protein ( SST neurons), eliminates normal breathing in adult rats. Whether preBötC SST neurons represent a functionally specialised population is unknown. We tested the effects on respiratory and vocal behaviors of eliminating SST neuron glutamate release by Cre‐Lox‐mediated genetic ablation of the vesicular glutamate transporter 2 ( VG lut2). We found the targeted loss of VG lut2 in SST neurons had no effect on viability in vivo , or on respiratory period or responses to neurokinin 1 or μ‐opioid receptor agonists in vitro . We then compared medullary SST peptide expression in mice with that of two species that share extreme respiratory environments but produce either high or low frequency vocalisations. In the Mexican free‐tailed bat, SST peptide‐expressing neurons extended beyond the preBötC to the caudal pole of the VII motor nucleus. In the naked mole‐rat, however, SST ‐positive neurons were absent from the ventrolateral medulla. We then analysed isolation vocalisations from SST ‐Cre; VG lut2 F/F mice and found a significant prolongation of the pauses between syllables during vocalisation but no change in vocalisation number. These data suggest that glutamate release from preBötC SST neurons is not essential for breathing but play a species‐ and behavior‐dependent role in modulating respiratory networks. They further suggest that the neural network generating respiration is capable of extensive plasticity given sufficient time.