Dihydrexidine (DAR-0100) is a moderately selective

full agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the a ...

at the dopamine D₁ and D₅ receptors. It has approximately 10-fold selectivity for D₁ and D₅ over the D₂ receptor. Although dihydrexidine has some affinity for the D₂ receptor, it has functionally selective (highly biased) D₂ signaling, thereby explaining why it lacks D₂ agonist behavioral qualities. Dihydrexidine has shown impressive antiparkinson effects in the MPTP-primate model, and has been investigated for the treatment of

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

. In an early

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel vaccines, drugs, diet ...

the drug was given intravenously and led to profound

hypotension Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...

was halted. The drug was resurrected when it was shown that smaller subcutaneous doses were safe. This led to a pilot study in

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wit ...

and current clinical trials to assess its efficacy in improving the cognitive and working memory deficits in

and schizotypal disorder. There have been several reviews of relevance to the compound.

References

D1-receptor agonists D2-receptor agonists D5 receptor agonists Catechols Biased ligands {{antihypertensive-stub