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  2. Synergistic effect between quinpirole and L-NAME as well as sulpiride and L-arginine on the modulation of anxiety and memory processes in the 6-OHDA mouse model of Parkinson's disease: An isobologram analysis

Synergistic effect between quinpirole and L-NAME as well as sulpiride and L-arginine on the modulation of anxiety and memory processes in the 6-OHDA mouse model of Parkinson's disease: An isobologram analysis

  • Neurobiol Learn Mem. 2021 Dec:186:107538. doi: 10.1016/j.nlm.2021.107538.
Mohammad-Reza Zarrindast 1 Soheila Fazli-Tabaei 2 Fatemeh Khakpai 3
Affiliations

Affiliations

  • 1 Department of Pharmacology School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran; Department of Neuroendocrinology, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
  • 2 Department of Physiology, Faculty of Medicine, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
  • 3 Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences, Islamic Azad University, Tehran, Iran. Electronic address: khakpai@iautmu.ac.ir.
Abstract

We evaluated interactions between dopamine D2 receptor and nitric oxide (NO) actions on the regulation of anxiety and memory in the 6-hydroxydopamine (6-OHDA) mouse model of Parkinson's disease (PD). A unilateral guide cannula was stereotaxically implanted over the right striatum. Elevated plus-maze test (EPM) test-retest protocol was employed to evaluate anxiety and memory in mice. The results revealed that injection of L-NAME (9 mg/kg) induced anxiolytic and amnesic effects, while L-arginine (9 mg/kg) produced anxiogenic and memory-improvement effects in the 6-OHDA mouse model of PD. Administration of sulpiride (20 mg/kg) induced anxiogenic and memory-improvement effects, whereas quinpirole (20 mg/kg) caused anxiolytic and amnesic effects in PD mice. Co-injection of sulpiride (5, 10, and 20 mg/kg) plus L-NAME (3 mg/kg) induced anxiolytic and amnesic effects. Co-injection of sulpiride (20 mg/kg) plus L-arginine (3 mg/kg) induced anxiogenic and memory-improvement effects. Co-administrations of quinpirole (20 mg/kg) and L-NAME (3 mg/kg) induced anxiolytic effect, but co-administration of quinpirole (20 mg/kg) plus L-arginine (3 mg/kg) caused anxiogenic and memory-improvement effects. The isobologram analysis revealed that there is a synergistic effect between sulpiride and L-arginine as well as quinpirole and L-NAME upon induction of anxiogenic and anxiolytic effects, respectively in PD mice. Our results suggested: (1) NO and dopamine D2 receptor mechanisms affect anxiety and memory in PD mice; (2) L-NAME reversed anxiogenic and memory-improvement effect induced by sulpiride; (3) Anxiolytic and amnesic effects induced by quinpirole reversed by L-arginine; (4) There is a synergistic effect between dopamine D2 receptor and NO systems on the modulation of anxiety and memory.

Keywords

Anxiety; Dopamine D2 receptor; Isobologram; Memory; Nitric oxide (NO); Parkinson's disease (PD).

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