Plasticity-Related Activity in the Hippocampus, Anterior Cingulate, Orbitofrontal, and Prefrontal Cortex Following a Repeated Treatment with D2/D3 Agonist Quinpirole

Abstract

Quinpirole (QNP) sensitization is a well-established model of stereotypical checking relevant to obsessive-compulsive disorder. Previously, we found that QNP-treated rats display deficits in hippocampus-dependent tasks. The present study explores the expression of immediate early genes (IEG) during QNP-induced stereotypical checking in the hippocampus, anterior cingulate cortex (ACC), orbitofrontal cortex (OFC), and medial prefrontal cortex (mPFC). Adult male rats were injected with QNP (0.5 mg/mL/kg; n = 15) or saline (n = 14) daily for 10 days and exposed to an arena enriched with two objects. Visits to the objects and the corners of the arena were recorded. QNP-treated rats developed an idiosyncratic pattern of visits that persisted across experimental days. On day 11, rats were exposed to the arena twice for 5 min and sacrificed. The expression of IEGs Arc and Homer1a was determined using cellular compartment analysis of temporal activity by fluorescence in situ hybridization. IEG-positive nuclei were counted in the CA1 area of the hippocampus, ACC, OFC, and mPFC. We found significantly fewer IEG-positive nuclei in the CA1 in QNP-treated rats compared to controls. The overlap between IEG expressing neurons was comparable between the groups. We did not observe significant differences in IEG expression between QNP treated and control rats in ACC, OFC, and mPFC. In conclusion, treatment of rats with quinpirole decreases plasticity-related activity in the hippocampus during stereotypical checking.

Neuroprotective effects of Quinpirole in lithium chloride pilocarpine-induced epilepsy in rats and its underlying mechanisms

“…Immunohistochemistry and Western blot analysis further corroborated the neuroprotective effects of Quinpirole. Notably, treatment with Quinpirole resulted in a denser arrangement and more regular morphology of granule cells in the hippocampus, indicating potential structural improvements [9].…”

Neuroprotective effects of quinpirole on lithium chloride pilocarpine-induced epilepsy in rats and its underlying mechanisms

“…Immunohistochemistry and Western blot analysis further corroborated the neuroprotective effects of quinpirole. Notably, quinpirole treatment resulted in a denser arrangement and more regular morphology of granule cells in the hippocampus, indicating potential structural improvements [ 9 ]. Additionally, quinpirole treatment decreased the protein expression of pro-apoptotic BAX and increased the protein expression of anti-apoptotic BCL2 [10.11].…”

Dopamine D3 Receptor: Contemporary Views of Its Function and Pharmacology for Neuropsychiatric Diseases

“…Numerous dopaminergic agonists have spectacular properties, such as the D2R/D3R agonist quinpirole. Brozka et al used repeated administration of this agonist to produce an obsessive–compulsive disorder-like behavior in rats [ 7 ] as classically described in the literature. Once the abnormal behavior was characterized, they looked at the expression of immediate early genes Arc and Homer1a in the brain using cellular compartment analysis of temporal activity by fluorescence in situ hybridization.…”