Amphetamines signal through intracellular TAAR1 receptors coupled to Gα13 and GαS in discrete subcellular domains.

The extensive use of amphetamines to treat attention deficit hyperactivity disorders in children provides a compelling rationale for understanding the mechanisms of action of amphetamines and amphetamine-related drugs. We have previously shown that acute amphetamine (AMPH) regulates the trafficking of both dopamine and glutamate transporters in dopamine neurons by increasing activation of the small GTPase RhoA and of protein kinase A. Here we demonstrate that these downstream signaling events depend upon the direct activation of a trace amine-associated receptor, TAAR1, an intracellular G-protein coupled receptor (GPCR) that can be activated by amphetamines, trace amines, and biogenic amine metabolites. Using cell lines and mouse lines in which TAAR1 expression has been disrupted, we demonstrate that TAAR1 mediates the effects of AMPH on both RhoA and cAMP signaling. Inhibition of different Gα signaling pathways in cell lines and in vivo using small cell-permeable peptides confirms that the endogenous intracellular TAAR1 couples to G13 and to GS α-subunits to increase RhoA and PKA activity, respectively. Results from experiments with RhoA- and PKA-FRET sensors targeted to different subcellular compartments indicate that AMPH-elicited PKA activation occurs throughout the cell, whereas G13-mediated RhoA activation is concentrated near the endoplasmic reticulum. These observations define TAAR1 as an obligate intracellular target for amphetamines in dopamine neurons and support a model in which distinct pools of TAAR1 mediate the activation of signaling pathways in different compartments to regulate excitatory and dopaminergic neurotransmission.

Crystal structures of 2,3-bis-(4-chloro-phen-yl)-1,3-thia-zolidin-4-one and trans-2,3-bis-(4-chloro-phen-yl)-1,3-thia-zolidin-4-one 1-oxide.

In the crystal structures of the title compounds, C15H11Cl2NOS, (1), and C15H11Cl2NO2S, (2), wherein (2) is the oxidized form of (1), the thia-zolidine ring is attached to two chloro-phenyl rings. The chloro-phenyl ring on the 2-carbon atom position points in the same direction as that of the S atom in (1), while in (2), the S atom points in the opposite direction. The O atom on the chiral S atom in (2) is trans to the chloro-phenyl ring on the 2-carbon. The chloro-phenyl ring planes in each structure are close to orthogonal, making dihedral angles of 78.61 (6) and 87.46 (8)° in (1) and (2), respectively. The thia-zolidine ring has a twisted conformation on the S-Cmethine bond in (1), and an envelope conformation with the S atom 0.715 (3) Šout of the plane of other four atoms in (2). In the crystal of (1), mol-ecules are linked by C-H⋯O hydrogen bonds, as well as by slipped parallel π-π inter-actions [inter-centroid distance = 3.840 (3) Å] between inversion-related phenyl rings, forming sheets parallel to (001). In the crystal of (2), mol-ecules are linked via C-H⋯O and C-H⋯Cl hydrogen bonds, forming slabs parallel to (001).