Elucidating the molecular pathways by which THC mediates its effect on D1 receptors could highlight potential molecular targets for therapeutic intervention. Indeed, studies have revealed numerous molecules involved in the THC-D1 molecular pathway. For example, with the application of THC, the expression of dopamine D1-D2 receptor heteromer increased sharply in nucleus accumbens. This was accompanied by a calcium-linked signaling increase and BDNF/TrkB pathway activation, dynorphin expression, and signaling of kappa opioid receptors . In other studies, the THC-induced phosphorylation of DARPP-32, a protein that responds to physiological and pharmacological stimuli by regulating electrophysiological, transcriptional, and behavioral responses , was inhibited by SCH-23390. This suggests that D1 receptors are preferentially expressed in a pathway that increases DARPP-32 phosphorylation in neurons by THC. Additionally, an intact D1 receptor and A2A, a receptor that interacts with dopamine receptors and modulates glutamatergic regulation of GABAergic and enkephalergic neurons, receptor is necessary for the action of THC, because phosphorylation of DARPP-32 at Thr34, which is important process for the indirect and direct pathway of striatal neurons, is represented by basal activation of those two receptors .