5-HT-induced outward currents are predominantly mediated by 5-HT1A receptor activation, and other Gi/o-linked GPCR activation-mediated outward currents were not changed in genotype. a In the presence of 5-HT1A receptor antagonist WAY100635 (500 nM), 5-HT-induced outward current was largely suppressed (Left trace). There was no difference in the amplitude of 5-HT-induced outward current (WT: 7.33 ± 2.75 pA, n = 6; 15q dup: 4.88 ± 2.27 pA, n = 6, t (10) = 0.70, p = 0.50; unpaired t-test). Bar graphs represent mean ± S.E.M. b Tests for other Gi/o-coupled receptor activation in both genotypes. GABAB receptor agonist baclofen (20 μM for 30 s) elicited large outward currents (Left traces) and exhibited statistically similar responses in both genotypes (WT: 123.50 ± 14.17 pA, n = 6; 15q dup: 107.22 ± 10.20 pA, n = 9, t (13) = 0.96, p = 0.36; unpaired t-test). Bar graphs represent mean ± S.E.M.