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Photostimulation of channelrhodopsin‐transfected rostral medullary Phox2b‐expressing neurons activates breathing in unaesthetized rats
Author(s) -
Kanbar Roy,
Stornetta Ruth L.,
Lewis Stephen J,
Guyenet Patrice G
Publication year - 2010
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.24.1_supplement.1026.10
Subject(s) - photostimulation , rostral ventrolateral medulla , respiratory system , chemistry , channelrhodopsin , medicine , endocrinology , respiratory rate , optogenetics , biology , neuroscience , medulla oblongata , heart rate , central nervous system , blood pressure
The Phox2b‐positive neurons of the RVLM were made to synthesize channelrhodopsin‐2 (ChR2) fused to mCherry (ChR2‐mCherry) by injecting a lentivirus that expresses the transgene under the control of the artificial promoter PRSX8. Labeled neurons consisted of ~62% C1 cells and ~38% retrotrapezoid (RTN) neurons. After 3–4 weeks, we examined the effect of photostimulation (~9 mW; 20 Hz, 10 ms pulses, 30 s) on breathing using plethysmography (10 rats) or diaphragmatic EMG (dEMG) recordings (4 rats). Photostimulation increased dEMG amplitude (19.2±7.4 %) and frequency (104±5 to 125±6 bursts/min, P <0.01). Photostimulation increased all plethysmographic respiratory variables including rate (from 76±3 to 108±5 breaths/min, P <0.0001), tidal volume (from 1.7±0.1 to 2.1±0.1 ml, P <0.001) and peak expiratory flow (from 7.9±0.6 to 9.7±0.9, P <0.05). In sum, the Phox2b‐expressing neurons of the RVLM regulate all aspects of breathing including inspiration and active expiration. We attribute these respiratory effects to the activation of RTN neurons but a small contribution of the C1 cells to these effects is not excluded (NIH support: HL 074011 & 28785).