. 2020 Jul 24;10:253. doi: 10.1038/s41398-020-00936-w

Table 2.

Escapable exposure studies specifying test used, delivery methods, concentration or flow rate used, strain and sex, and summary of results. In all choice and aversion tests all rats avoided CO₂ before loss of consciousness.

Strain	Sex	Test	Delivery method	Concentration/flow rate	Variables measured	Results	Notes	Reference
W	F	Choice	Pf	100% air	Total dwelling time	>35 s		⁴
				25.5% CO₂		1.9 ± 0.6 s
				34.9% CO₂		0.8 ± 0.1 s
				50.8% CO₂		0.7 ± 0.1 s
W	F	Choice	Pf	100% air	Total dwelling time	>36 s		⁵
				25.5% CO₂		2.1 ± 0.5 s
				34.9% CO₂		1.0 ± 0.1 s
				50.8% CO₂		0.7 ± 0.2 s
SD	M	Aversion-avoidance	Gf	32% O₂	Total dwelling time	~90 s^a		³⁹
SD	M	Aversion-avoidance	Gf	24% CO₂	Total dwelling time	19 ± 5 s and 24 ± 3 s	Depending on the level of illumination of the light chamber	³⁹
SD	F	Aversion-avoidance	Gf	19% CO₂	Latency to avoid CO₂	33 ± 6 s and 35 ± 4 s	Two consecutive exposures	²⁷
SD	F	Aversion-avoidance	Gf	19% CO₂	CO₂% avoided	14 ± 2% and 15 ± 1%	Two consecutive exposures	²⁷
W	M	Approach-avoidance	Pf	100% air	Total dwelling time	~ 240 s^a		⁴¹
				5% CO₂		~ 230 s^a
				10% CO₂		~ 225 s^a
				15% CO₂		46 s^b
				20% CO₂		5 s^b
W	M	Approach-avoidance	Gf	17% CO₂	CO₂% avoided	18.4 ± 2%		⁴¹
W	M	Approach-avoidance	Gf	21% air	Latency to leave the chamber	270 ± 6 s		⁸
				3–27% CO₂	Latency to avoid CO₂	↓ from ~ 95 s ^a to ~ 28 s^a	Depending on flow rate
				3–27% CO₂	CO₂% avoided	14–16%^a
W	M	Approach-avoidance	Gf	17% air	Latency to leave the chamber	288 ± 2 s		⁷
W	M	Approach-avoidance	Gf	17% CO₂	Latency to avoid CO₂	40 ± 2 s	Average from three consecutive exposures	⁷
W	M	Approach-avoidance	Gf	15% CO₂ (Exp. 1)	CO₂% avoided	16.3 ± 0.3%	Average from different levels of food deprivation	⁴⁰
W	M	Approach-avoidance	Gf	15% CO₂ (Exp. 2)	CO₂% avoided	13.6 ± 0.3%	Average from different levels of food deprivation	⁴⁰
SD	F	Approach-avoidance	Gf	18% O₂	Latency to leave the chamber	237 ± 27 s		²⁷
				18.5% CO₂	Latency to avoid CO₂	23 ± 4 s and 28 ± 4 s	Two consecutive exposures
					CO₂% avoided	9 ± 2 % and 11 ± 1 %
SD	F	Approach-avoidance	Gf	20% air	Latency to leave the chamber	420 ± 27 s	Average from three exposures	⁴²
				Midazolam + 20% air		391 ± 28 s	Average from three exposures
				20% CO₂	Latency to avoid CO₂	25 ± 2 s	Average from three exposures
					CO₂ % avoided	10.7 ± 1.14%
SD	F	Approach-avoidance	Gf					⁴²
				Midazolam + 20% CO₂	Latency to avoid CO₂	40 ± 3 s	Average from three exposures
					CO₂ % avoided	15.5 ± 1.41%

Strain: W Wistar, SD Sprague Dawley; delivery method: Pf pre-fill, Gl gradual fill; concentration or flow rate: static concentration (%) or flow rate (% gas chamber vol. min⁻¹); sex: M male, F female; s seconds; results mean ± standard error (unless specified otherwise); Exp. experiment.

^aAverage values estimated from a figure.

^bMedian values.