Fig. 8: Dopamine induced interference of polysynaptic inhibition is mediated by D2 receptors.

a, b Fast scan cyclic voltammetry measurements indicate light-evoked dopamine release in DAT-Cre, but not VGAT-Cre animals (n = 10 recording sites in each condition, p = 0.000091, two-sided Kolmogorov–Smirnov test). Boxplots indicate minimum, first quartile, median, third quartile, and maximum. c Example of polysynaptic responses exhibiting light-induced interference, which is abolished in the presence of D2 antagonists eticlopride and sulpiride. d Interference is reduced when light evoked dopamine release is combined with bath application of D1 receptor antagonist SCH-23390 from 39% to 30% (n = 29 connections, p = 0.013, two-tailed paired samples t-test), but more strongly inhibited in the presence of D2 receptor antagonists eticlopride and sulpiride from 36% to 7% (n = 32 connections, p = 0.005, two-tailed paired samples t-test). e PI is abolished following bath application of quinpirole but partially recovers following a 30 min wash-out. f PI is reduced in the presence of D1 agonist SKF-81297 from 4.2 mV to 2.9 mV (n = 22 connections, p = 0.006, two-tailed Wilcoxon signed-ranks test) and abolished in the presence of D2 agonist quinpirole from 6.5 mV to 0.3 mV (n = 20 connections, p = 0.000089, two-tailed Wilcoxon signed-ranks test). g Example of PI mediated pause in a postsynaptic ChIN. The presynaptic action potential time is marked with a red dashed line. The pause is blocked following bath application of D2 receptor agonist quinpirole. h, i Postsynaptic response amplitude in a Striatal ChIN during quinpirole wash-in for light evoked input from TH neurons (red) and feed-forward polysynaptic inhibition (black), or DhβE wash-in on feed-forward inhibition (orange). Input from TH neurons shows gradual attenuation, while polysynaptic inhibition is abruptly gated by either DhβE or quinpirole.