Fig. 3: Conformable electronics enable in vivo acquisition of distinct gut electrophysiological responses to various in vivo pharmacological stimuli.
Representative responses for (a) topical administration of 1 µM bradykinin, b topical administration of 500 nM capsaicin, and c intraluminal administration of 500 nM capsaicin (administered per the overall regimen shown in Supplemental Fig. 5), showing (i) spectrogram (0−2000 Hz) of power spectral density (PSD), (ii) raw voltage signal. Drug administration occurred at approximately t0 for (a–c). Asterisk in c indicates initial high frequency response as discussed in the text. Power spectra corresponding to each data point, tb, t0, t1, t2, t3 in the spectrograms for each drug are shown in Supplemental Fig. 6. d Normalized response per animal to different drug additions (n = 6 rats, independent experiments). The response activity elicited by each drug was quantified with the maximum [dB/(Hz*s)], mean [dB/(Hz*s)], and variance {[dB/(Hz*s)]2} of the temporal power spectral density (PSD), computed as the area under the curve (AUC) of the spectrogram power data using non-overlapping 1 s rolling windows. The responses were normalized [0,1] to the maximum and minimum values obtained among all additions (including saline) to allow for meaningful comparisons. Statistical summary: Mann-Whitney U Test: aU = 0.0, p = 0.0034, bU = 3.0, p = 0.015, cU = 5.0, p = 0.04, dU = 0.0, p = 0.0034, eU = 3.0, p = 0.016; Bar plots overview: Max - saline (0.05 ± 0.12), bradykinin(0.71 ± 0.33), capsaicin topical (0.26 ± 0.41), capsaicin intraluminal (0.54 ± 0.51); µ - saline (0.12 ± 0.21), bradykinin(0.66 ± 0.41), capsaicin topical (0.25 ± 0.39), capsaicin intraluminal (0.55 ± 0.50); Var - saline (0.01 ± 0.03), bradykinin(0.60 ± 0.44), capsaicin topical (0.20 ± 0.40), capsaicin intraluminal (0.51 ± 0.54); e, e, f, Administration of bradykinin for (e) and (f) was performed as follows: 1st addition, 2nd addition, saline wash, 3rd addition, 4th addition, saline wash, 5th addition, saline wash, 6th addition. e Mean of the temporal PSD (300–2000 Hz) for an initial and secondary administration of bradykinin (repeated twice, separated 2 to 3 min in between—1st and 3rd additions compared to the 2nd and 4th) with no intermediate saline wash (n = 4 rats, independent experiments). Error bars: first (0.43), second (0.35). f Mean of the temporal PSD (300–2000 Hz) for 4 additions of bradykinin with at least one saline wash step in between (n = 4 rats, independent experiments). 1st addition compared to the 3rd, 5th, and 6th (Mann-Whitney U-test: *1st vs. 5th U = 16.0, p = 0.0265; **1st vs. 6th, U = 16.0, p = 0.0265; Error bars: first (0.09), second (0.37), third (0.19), fourth (0.06). Isoflurane was kept at 1.3% for the whole duration of the recordings.
