Quinpirole Effects on the Dopaminergic System

Quinpirole (QNP) is a D2-like dopamine (DA) receptor agonist with some selectivity for D3 receptors, and it is the active enantiomer of quinpirole dihydrochloride. The objective of the present article is to review the available evidence published about dopamine in the Central and Peripheral Nervous System (CNS, PNS) and QNP with an emphasis on their receptors effects, the physiological and molecular changes in CNS cells. Dopaminergic neurons are the most important cells regarding reward-related behavior; they are also involved in many neuroanatomical pathways and different functions both in central (locomotion control, cognition, motivation, learning, sleep-wake cycles, etc.), peripheral and autonomous nervous system; however, the correlation between dopamine release and cell firing is unclear. Also, other cellular mechanisms regarding DA have not been completely studied. This is why animal models with rats and QNP are still used for studying the role of DA and its physiological and pathological implications in the nervous system. Animal models of Obsessive-Compulsive Disorder (OCD) have been successfully reproduced in rats with the manipulation of dopaminergic system using QNP, as an association between the dopaminergic system and the production of compulsive behaviors has been evidenced. Moreover, QNP and DA modulate neurons through the activation of cytoplasmic cascades, intracellular receptor stimulation and even through gene transcription regulation.