Fig. 1
Repeated chemogenetic stimulation of DA neurons during adolescence induces reversible decreases in AMPH-induced stereotypic behavior. a (Left) Schematic of viral injection and representative sections from the midbrain region of TH-CrehM3Dq mice. Scale bar: 50 um. (Right) Experimental timeline. Surgeries were conducted in postnatal day 1 (P1) pups. CNO (1.0 mg/kg IP, 1 × daily) was administered from P15 to P47 (Experimental Days 0–32 = ‘CNO phase’). CNO, saline, and AMPH-induced locomotion and stereotypy were tested during the CNO phase. Mice were again tested one month and two months after stopping CNO during Washout phases 1 and 2. b-d, f TH-CrehM3D(Gq) mice show progressive increases in CNO-induced hyperlocomotion from Days 7–18. Repeated CNO does not impact baseline (pre-injection) locomotion in TH-CrehM3D(Gq) mice. e, g Locomotor activity after IP saline is unaltered in TH-CrehM3D(Gq) mice. h TH-CrehM3D(Gq) mice show decreased AMPH (3.0 mg/kg)-induced hyperlocomotor response relative to WThM3D(Gq) mice after repeated CNO via curve fit analysis, but not via 2-way RM ANOVA. (i) TH-CrehM3D(Gq) mice show diminished AMPH (8.0 mg/kg)-induced stereotypic behavior in CNO phase via three-way ANOVA. j, k, m, n No genotype difference in baseline and AMPH-induced locomotion is observed after one month and two months of CNO washout. l, o No genotype difference in AMPH-induced stereotypy is observed after one month and two months of washout. p-r No genotype difference in baseline and AMPH-induced locomotor response is observed across CNO and Washout phases via Linear Mixed Model (LMM). s TH-CrehM3D(Gq) mice show decreased AMPH-induced stereotypic behavior in CNO phase and recovery of AMPH response after CNO washout via LMM. (N = 13 TH-CrehM3Dq and 10 WThM3Dq mice. Two-way treatment x genotype interaction, ###P < 0.001, #P < 0.05; genotype effect, **P < 0.01, *P < 0.05; Holm-Sidaks’s multiple comparisons, σσP < 0.01, σP < 0.05. nsP = not significant. Also see Additional Figs. S1-3 and Additional Table 1.)