. 2018 Feb 21;4(2):eaaq0800. doi: 10.1126/sciadv.aaq0800

Table 1. Cardiorespiratory and HRV parameters in L. paradoxa.

Experimental conditions: after instrumentation (Post-surgery; n = 9), recovered resting fish (Control; n = 8), with cholinergic receptor blockade (Atropine; n = 6), or total blockade of β-adrenergic and cholinergic receptors (Atropine + Propranolol; n = 6). Following instrumentation, lungfish was allowed to recover for at least 24 hours before measurements. Data are means ± SEM. Different superscript letters indicate significant differences [analysis of variance (ANOVA) with Tukey’s post hoc test, P < 0.05]. SDNN, SD of all normal-to-normal intervals; RMSSD, square root of the mean squared differences between each successive RRi and the mean interval; PSD, power spectral density.

Parameters	Experimental groups
Parameters	Post-surgery	Control	Atropine	Atropine + Propranolol
O₂ uptake per breath (ml breath⁻¹ kg⁻¹)	0.11 ± 0.02^A	0.83 ± 0.07^B	0.29 ± 0.05^A,C	0.43 ± 0.08^C
$\dot{V}$ O₂ (ml kg⁻¹ hour⁻¹)	23.6 ± 1.8^A	10.6 ± 0.8^B	24.2 ± 3.1^A	20.4 ± 2.5^A
f_R (breaths hour⁻¹)	11.5 ± 1.7^A	1.7 ± 0.1^B	7.3 ± 1.5^C	5.9 ± 1.6^C
Tidal volume (ml kg⁻¹)	27.9 ± 1.8^A	25.3 ± 1.6^A	26.7 ± 1.7^A	34.1 ± 1.9^B
Air-breathing cycle (s)	8.8 ± 0.4^A	9.5 ± 0.4^A	8.6 ± 0.3^A	9.7 ± 0.4^A
f_H (beats min⁻¹)	38.8 ± 1.4^A	29.5 ± 1.5^B	39.2 ± 1.9^A	36.3 ± 2.2^A
RR mean (ms)	1547.4 ± 58.8^A	1,947.7 ± 74.7^B	1548.8 ± 69.8^A	1682.8 ± 90.4^A
RR variance (ms²)	4953.2 ± 1187.8^A	28,244.1 ± 3,344.7^B	1834.9 ± 491.5^A	3690.9 ± 1311.4^A
SDNN (ms)	66.6 ± 8.1^A	192.4 ± 16.5^B	40.4 ± 6.3^A	54.9 ± 11.7^A
RMSSD (ms)	40.7 ± 4.2^A	102.8 ± 9.8^B	22.5 ± 5.5^A	19.9 ± 4.9^A
PSD (ms²)	3664.0 ± 437.3^A	26,957.5 ± 2,791.1^B	998.9 ± 364.7^A	2903.7 ± 970.1^A