Synaptic up-scaling preserves motor circuit output after chronic, natural inactivity
- University of Missouri-Columbia, United States
- Wright State University, United States
Figures
Figure 1
Vagal motoneurons predominately innervating the glottal dilator were labeled by backfilling the 4th (most caudal) root of the IX-X cranial nerve complex.
(A) illustrates the tetramethylrhodamine-dextran (TRITC) backfill procedure. Orange line across brainstem approximates where brainstem slices were taken for experiments. (B and C) show examples …
Figure 2
Respiratory motoneurons have increased synaptic strength after winter inactivity.
1A shows example voltage clamp traces of miniatures excitatory postsynaptic currents (mEPSCs; holding potential= −80 mV; 500 nM TTX) in control (green) and winter inactivity (blue) frogs. 2B shows …
Figure 3
Winter inactivity scales up mEPSCs in respiratory motoneurons.
Figure 3A shows linear, but not exponential, scaling of mEPSC amplitudes. Control and winter inactivity mEPSC amplitudes were rank ordered (50 mEPSCs in n = 16 neurons from each group; 800 total …
Figure 4
Increases in F-I (frequency-current) gain do not accompany up-scaling of excitatory synapses.
Figure 4A shows example current clamp recordings of control (green) and winter inactivity (blue) motoneurons during step current injections (+50 pA X 20 steps; 0.5 s per step). Figure 4B shows mean …
Figure 5 with 1 supplement
Increases in AMPA-glutamate receptors sustain motor output from the respiratory network after winter inactivity.
Figure 5A illustrates the bullfrog in vitro brainstem-spinal cord preparation. In bullfrogs in vivo, lung ventilation cycles involve activation of both glottal dilator (value to the lung) and buccal …
Figure 5—figure supplement 1
Respiratory burst amplitude from each winter inactivity bullfrog tends to recover upon washout (A. winter inactivity group: paired t test; p=0.0351; DNQX vs. washout) and returns to near-control values (one sample t test; p=0.0333 compared to 100% during DNQX and p=0.0609 during washout, n = 4).
Burst amplitudes from control frogs do not differ between DNQX and washout (B. DNQX vs. washout; p=0.3113) and were not different than 100% of baseline during DNQX or washout (one sample t test; …
Additional files
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Supplementary file 1
Statistical information for all analyses performed in the paper.
- https://doi.org/10.7554/eLife.30005.009
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Transparent reporting form
- https://doi.org/10.7554/eLife.30005.010
