Multi-dimensional oscillatory activity of mouse GnRH neurons in vivo
- Department of Physiology, Development and Neuroscience, Downing site, University of Cambridge, United Kingdom
- Zurich Center for Neuroeconomics, Department of Economics, University of Zurich, Switzerland
Figures
Figure 1
GCaMP expression in gonadotropin-releasing hormone (GnRH) neurons.
(A) Photomicrographs at the level of organum vasculosm of the laminae terminalis (OVLT) showing GFP immunofluorescence representing GCaMP6 (green), GnRH (purple), and merged channels showing double labeled cells (white). (B) Photomicrographs from four mice at the level of arcuate nucleus showing the location of the end of the optic fiber (dotted line) in relation to GnRH neuron dendrons labeled with GnRH (red), GFP representing GCaMP6 (green) in merged channels where double labeled elements are yellow. 3 V, third ventricle.
Figure 2
Gonadotropin-releasing hormone (GnRH) neuron dendron activity in male mice.
(A) A representative example of 24 hr GCaMP6 photometry recording showing abrupt dendron synchronized episodes (dSEs) occurring on lower amplitude baseline activity in a male mouse. Below, an expanded view of the trace indicated by the horizontal line. (B) Example of 8 hr GCaMP6 photometry recording in a male mouse with a misplaced fiber optic. All recorded signals are under 3% of baseline. Below, an expanded view of the trace indicated by the horizontal line. (C) Average high-resolution profile of a dSE in male mice (N=7 mice) showing a rapid onset followed by a gradual decrease back to baseline. ‘a’ and ‘b’ gives values at full-width half maximum (FWHM). (D) Inter-peak intervals combined from all recordings (n=96 dSEs) displayed as a percentage of all intervals occurring in 10 min bins. W=0.87, p<0.0001****, Shapiro Wilk normality test. Skewness=1.39, Kurtosis=1.81. (E) Representative example showing the relationship of dSEs (black) to pulsatile luteinizing hormone (LH) secretion (red). (F) Normalized increase in LH plotted against dSEs, with the time 0 being the peak of dSE.
Figure 3
Gonadotropin-releasing hormone (GnRH) neuron dendron activity in female mice.
(A) Representative example of 6 hr GCaMP6 photometry recordings from a female mice in (i) metestrus, (ii) diestrus, (iii) proestrus, and (iv) estrus. To the right of each trace are histograms showing the mean inter-peak intervals for dendron synchronized episodes (dSEs) from all recordings across metestrus (n=53 dSEs), diestrus (n=88 dSEs), proestrus (n=62 dSEs), and estrus (n=42 dSEs) displayed as a percentage of all intervals occurring in 10 min bins. (B) Histograms showing inter-peak intervals of dSEs across the estrous cycle. M=metestrus (N=8), D=diestrus (N=8), P=proestrus (N=6), E=estrus (N=5). *p<0.05, **p<0.01, Kruskal Wallis followed by Dunn’s post-hoc test. (C) Average high-resolution profile of dSEs in female mice showing a rapid onset followed by a gradual decrease in the signal. ‘a’ and ‘b’ show the values at full-width half maximum (FWHM). (D) A representative example showing the relationship of dSEs (black) to pulsatile LH secretion (red). (E) Normalized change in LH (red) plotted against normalised dSEs, with the time 0 being the peak of the dSE.
Figure 4
Baseline high-frequency cluster activity of gonadotropin-releasing hormone (GnRH) neuron dendrons in male and female mice.
Representative 4 hr GCaMP recordings in (A) two male mice and (B) a female mouse across the different stages of the estrous cycle showing high-frequency baseline activity. The large increases in calcium activity representing dendron synchronization episodes (dSEs) are indicated by red asterisks and cut off to optimize the display of the low amplitude activities. Histograms showing the duration (C) and the intra-cluster frequency (D) of the baseline activity in male and female mice. No significance was found across the groups. M=metestrus, D=diestrus, P=proestrus, E=estrus.
Figure 5
Slow oscillating increases in calcium activity on the afternoon of proestrus in female mice.
(A) Examples of 21 h GCaMP recordings from four proestrous female mice. Note the prolonged (>10 hr) gradual oscillating increase in calcium signal beginning on the afternoon of proestrus. The sharp dendron synchronized episodes (dSEs) continue until approximately the plateau phase of the increased baseline at which time they stop or slow. (B) A representative example showing the relationship between the slow increase in baseline calcium activity (black) with luteinizing hormone (LH) surge (red). Note that the rise in LH occurs alongside the initial rise in calcium activity but returns to baseline several hours before the calcium signal.
Figure 6
Deconvolution of the GCaMP signal across the proestrous surge reveals multimodal activity patterns of gonadotropin-releasing hormone (GnRH) neuron dendron.
(A–B) Representative examples of 24 hr photometry recordings from two female mice starting at proestrus showing (i) the original recording, (ii) a 30 min rolling average highlighting the luteinizing hormone (LH) surge signal (red), (iii) the LH surge signal subtracted from the original recording, displaying the dendron synchronized episodes (dSEs) (blue), and (iv) the residual baseline signal (pink) after subtracting both the surge and pulse profiles.
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Multi-dimensional oscillatory activity of mouse GnRH neurons in vivo
eLife 13:RP100856.
https://doi.org/10.7554/eLife.100856.3
