Table 1.

Behavioral responses of DAT-cre mice under isoflurane CSSGA during optical stimulation of the VTA

Group	Drug treatment	Leg movement	Head movement	Whisker movement	Righting	Walking	Total score
ChR2+	NS	2	2	2	2	1	9
ChR2+	NS	2	2	2	2	1	9
ChR2+	NS	2	2	2	2	2	10
ChR2+	NS	2	2	2	2	2	10
ChR2+	NS	2	2	2	2	1	9
ChR2+	NS	2	2	2	2	2	10
ChR2+	SCH	1	0	0	0	0	1
ChR2+	SCH	1	0	0	0	0	1
ChR2+	SCH	1	1	0	0	0	2
ChR2+	SCH	1	0	0	0	0	1
ChR2+	SCH	1	0	0	0	0	1
ChR2+	SCH	1	0	0	0	0	1
ChR2−	NS	1	1	0	0	0	2
ChR2−	NS	1	1	0	0	0	2
ChR2−	NS	1	0	0	0	0	1
ChR2−	NS	1	1	0	0	0	2
ChR2−	NS	1	1	0	0	0	2

The arousal scoring system was adapted from Reed et al. (54). Leg, head, and whisker movements were scored as absent, mild, or moderate in intensity (0, 1, or 2, respectively) during 30 min of optical VTA stimulation while mice continuously inhaled 0.8 to 0.9% isoflurane. Righting was scored as 0 if the mouse remained prone, and 2 if all four paws touched the ground. Walking was scored as 0 if the mouse made no further movements after righting, 1 if it crawled but did not raise its abdomen off the floor, and 2 if it walked on four paws with its abdomen off the floor. The total score for each animal is the sum of all categories, with a maximum possible score of 10. Mice were treated with either SCH-23390 (SCH) or normal saline (NS). The total score of ChR2+ mice was significantly higher than ChR2+ mice after SCH-23390 administration (P = 0.0022) and ChR2− mice (0.0043), as determined using a Mann–Whitney U test. The total scores of ChR2+ mice after SCH-23390 administration and ChR2− mice were not significantly different (P = 0.1342).