Quinpirole for ADHD
There is no description of any useful use of quinpirole in ADHD.
The presentation is for the sake of completeness only.
Quinpirole is a selective D2 and D3 agonist.1
Quinpirole decreases dopamine levels in the left PFC but increases them in the striatum and amygdala.2
Hypermotor skills and compulsive behaviors are increased.
Whether this amplification of hypermotor activity also occurs in ADHD-HI/ADHD-C sufferers is open to question. Hyperactivity is located in the striatum. However, symptoms are caused by a non-optimal neurotransmitter level, in this case hyperactivity due to dopamine deficiency as well as dopamine excess.
If quinpirole raises dopamine levels in the striatum, it is plausible that hyperactivity symptoms will occur in unaffected individuals.
In ADHD-HI and ADHD-C, however, there is a dopamine deficit in the striatum. It should follow from this that quinpirole eliminates this deficit and thus reduces hyperactivity at the same time.
In ADHD, a dopamine deficiency in the PFC is further hypothesized. A further reduction in dopamine levels would therefore be detrimental.
However, in ADHD, it is primarily the medial and right PFC that is affected.
How detrimental quinpirole’s reduced dopamine levels in the left PFC are in ADHD is an open question.
Besides, quinpirole - as well as aripiprazole (Abilify), a partial D2 receptor agonist - reduces cue-induced wanting to cocaine in adult (but not young) rats and thus may help with addiction problems.3
Another study in rats showed significant THC-like effects of quinpirole when metabolic degradation of anandamide was inhibited, supporting the hypothesis that these effects of quinpirole are mediated through cannabinoid CB1 receptors.4
Sullivan, Talangbayan, Einat, Szechtman (1998): Effects of quinpirole on central dopamine systems in sensitized and non-sensitized rats. Neuroscience. 1998 Apr;83(3):781-9 ↥
Zbukvic, Ganella, Perry, Madsen, Bye, Lawrence, Kim (2016): Role of Dopamine 2 Receptor in Impaired Drug-Cue Extinction in Adolescent Rats; Cereb. Cortex (2016) 26 (6): 2895-2904. doi: 10.1093/cercor/bhw051 ↥
Solinas, Tanda, Wertheim, Goldberg (2010): Dopaminergic augmentation of delta-9-tetrahydrocannabinol (THC) discrimination: possible involvement of D2-induced formation of anandamide; Psychopharmacology (Berl). 2010 Apr; 209(2): 191–202. doi: 10.1007/s00213-010-1789-8; PMCID: PMC2834964; NIHMSID: NIHMS180022 ↥