Fig. 3: Activation of D1Rs in MSNs of the DMS with MP-D1ago enhances movement.
From: Cell specific photoswitchable agonist for reversible control of endogenous dopamine receptors
A D1R and its close homolog D5R are widely expressed in the brain (left panel) and are present in multiple cell types in the dorsal striatum (dStr; right panel). D1R is also expressed in the terminals of some glutamatergic afferents that innervate the striatum. DMS-dMSN D1Rs were selectively targeted with MP-D1ago (red), which is composed of the membrane-anchor MEAAAK:ERE and P-D1ago. B The M was virally delivered to DMS-dMSNs. Its expression (red = HA-tag staining) can be seen within the dStr. P-D1ago and light were delivered the dStr with a reversible infusion/optical cannula. grey bar = 100 µm. blue = DAPI staining. Representative of brains from n = 7 mice. C The M is present at the surface of dStr-dMSNs according to its ability to bind the impermeant SNAP-tag binding dye SNAP-Surface Alexa Fluor 647. Labeling was not observed in the absence of the M or dye. mVenus (green) is an indicator of viral infection. grey bars = 50 µM. Representative of brains from n = 3 mice. D D1-Cre mice injected with an AAV encoding mVenus or the M and mVenus received bilateral dStr-infusions (1 µL) of either vehicle or the inactive form of P-D1ago (cis; 100 µM) three hours prior to being placed in an open field. Locomotor activity of MP-D1ago mice was measured in an open field. UV light and blue light were delivered to both sides of the brain. E The speed of mice with MP-D1ago in dStr-dMSNs increased in response to a brief flash (450 nm, ~6 mW, 1 s) of blue light and returned to baseline after a brief flash (375 nm, ~9 mW, 1 s) of UV light. The behavioral response was not observed in mice lacking the M and/or P-D1ago (400 nL infusion in each hemisphere). F The speed of each mouse was averaged over the following two-minute periods: (i) just before exposure to blue light (UV pre), (ii) three minutes after exposure to blue light (blue), (iii) and one minute after exposure to the second flash of UV light (UV post). See Supplementary Fig. 15a for more detail. Shown is a summary of the speed of -M or +M mice treated with vehicle or P-D1ago mice during the UV pre, blue, and UV post periods. RM one-way ANOVA, F-values from left to right: 0.2, 0.4, 0.1, 15.4, Bonferroni, *p < 0.05. n = 7 mice for each condition. G The behavioral photoeffect was not observed in the presence of the D1R antagonist SCH23390 (0.5 mg/kg). Error bars indicate S.E.M.
