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Optical stimulation of Channel Rhodopsin2(ChR2)‐transfected retrotrapezoid nucleus (RTN) neurons activates breathing
Author(s) -
Abbott Stephen Bruce Gidley,
Stornetta Ruth L,
West Gavin H,
Guyenet Patrice G
Publication year - 2009
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.23.1_supplement.621.10
Subject(s) - stimulation , transfection , neuroscience , biology , transgene , chemistry , medicine , gene , biochemistry
The role of the RTN neurons in breathing is not definitely established. RTN neurons are Phox2b‐expressing, glutamatergic, non‐TH, acid‐sensitive and innervate regions involved in respiratory rhythm generation. Using a lentivirus with the ChR2‐mCherry fusion protein under the PRSX8 promoter (with 8 copies of the Phox2 transcription factor response site), we drove expression of ChR2‐mCherry to Phox2b neurons with >92% selectivity. Appropriately targeted microinjections of the virus restricted transgene expression to the RTN and nearby C1 adrenergic neurons (2.7/1 non TH/TH in control rats and 5/1 in rats with selective lesions of C1 cells). Activation of the ChR2‐transfected neurons with 470 nm; 20 Hz, 10 ms pulses, 30s trains of pulsed laser light (LL) produced large increases in phrenic nerve discharge (PND), a 5mmHg increase in BP and a 10% rise in sympathetic nerve discharge (SND). PND activation decayed slowly after turning off LL (t 1/2 =11.8s) whereas SND activation returned to control within seconds. LL increased PND equally in control and C1‐lesion rats with no BP change in the latter. LL had no effect on PND or BP in animals with RTN transfection using control lentivirus of comparable titer. In summary, activation of RTN stimulates respiratory activity with a slow time course consistent with a chemoreceptor role, whereas C1 neuron stimulation primarily affects BP.