Delay-dependent modulation of memory retrieval by infusion of a dopamine D? agonist into the rat medial prefrontal cortex.

Dopamine (DA) in the medial prefrontal cortex (PFC) can modulate the short-term retention of information and other executive functions. The present study examined whether administration of a DA D? agonist into the PFC could have differential effects on memory retrieval in circumstances in which memory was either excellent or poor. Separate groups of rats were trained on a delayed version of the radial maze task. On the test day, the delay between the phases was either 30 min or 12 hr. Infusions of the D? receptor agonist SKF 81297 (0.05, 0.10, or 0.20 Ag/0.5 P1) into the PFC before the test phase improved memory retrieval after a 12-hr delay but disrupted performance after a 30-min delay. These data suggest that D? receptor activity can exert differential effects over PFC function, depending on the strength of the memory trace. When memory is decremented by an extended delay, activation of PFC DA D? receptors by an agonist can improve cognitive function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

~(99)Tc~m标记多巴胺D_2受体配体的合成,标记及生物分布研究

首次合成了 3种苯酰胺类D2 受体配体 :N [(2 巯基 )乙基 ] 2 ,3 二甲氧基苯甲酰胺 (MEDM BZM) ,N [(2 巯基 )乙基 ] 5 溴 2 ,3 二甲氧基苯甲酰胺 (MEBDM BZM ) ,N [(2 巯基 )乙基 ] 3 乙氧基苯甲酰胺 (MEE BZM) ,光谱数据与结构相符。用配体交换法与 3 硫杂 1,5 戊二硫醇共同配位合成了中性脂溶性的“3+ 1”型混配99Tcm 螯合物 ,标记率大于 85 %。 3种配合物在小鼠脑中的初始摄取率高于文献报道值     

Dopaminergic modulation of olfactory bulb processing affects odor discrimination learning in rats.

Olfactory behavioral studies have shown that, when modulated through systemic injections, D1 and D2 receptors have opposing effects on odor discrimination learning. In the present study, cannulated male Sprague–Dawley rats were used to investigate how the modulation of these 2 types of dopaminergic receptors through direct infusion of D1/D2 agonists and antagonists into the olfactory bulb affect olfactory perception. Dopaminergic modulation was locally altered by manipulations of D1 (agonist SKF 82958: 14.6, 43.8, & 143.6 mM; antagonist SCH-23390: 13.4, 40.1, & 60.1 mM) and D2 (agonists quinpirole: 78.2, 117.3, & 156.4 mM; antagonist sulpiride: 0.3, 0.9, & 2.9 mM) receptors during a simultaneous odor discrimination task. The authors found that modulation of D2, but not D1, receptors significantly affected rats’ odor discrimination performance. A significant positive correlation between blockade of D2 receptors and discrimination performance, as well as a significant negative correlation between D2 receptor activation and discrimination performance, was observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in nicotine sensitization and conditioned hyperactivity in adolescent rats neonatally treated with quinpirole: Role of D2 and D3 receptor subtypes.

Neonatal quinpirole treatment in rats produces increased sensitivity of dopamine D2-like receptors throughout the animal’s lifetime, referred to as D2 priming. There is little information on the effects of nicotine in adolescent rats, especially in a model that has clinical relevance to psychosis where increased D2 receptor sensitivity is common. Male and female rats were treated with quinpirole (1 mg/kg) or saline from postnatal (P) day 1–P21, given nicotine (0.5 mg/kg) or saline from P33 through P49, and placed into a locomotor arena for behavioral testing. Nicotine or saline treatment was preceded by the D2-like receptor antagonist eticlopride, D3 antagonist nafadotride, or saline. Conditioned hyperactivity was analyzed on P50 in the same context in a drug-free test. In females, D2 priming increased the locomotor response to acute nicotine, but did not affect subsequent nicotine sensitization, and only non–D2-primed females demonstrated conditioned hyperactivity. Eticlopride and nafadotride blocked behavioral sensitization, although nafadotride was more effective at blocking nicotine-conditioned hyperactivity in females. In males, D? priming enhanced sensitization to nicotine and produced conditioned hyperactivity, which were blocked by eticlopride and nafadotride. These results have implications for psychosis and comorbidity of nicotine abuse in adolescence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic Study Identifies CBLN4 as a Novel Susceptibility Gene for Accident Proneness

Frequent traffic accidents constitute a major danger to human beings. The accident-prone driver who has the stable physiological, psychological, and behavioral characteristics is one of the most prominent causes of traffic accidents. The internal link between the individual characteristics and the accident proneness has been a difficult point in the accident prevention research. The authors selected accident-prone drivers as cases and safe drivers as controls (case-control group) from 18,360 drivers who were enrolled from three public transportation incorporations of China using area stratified sampling method. The case-control groups were 1:1 matched. The authors performed genome-wide association study (GWAS) by 179 cases and 179 controls using the U.S. Affymetrix Genome-Wide Human Mapping SNP 6.0 Array. The authors observed that the gene frequencies of 34 single-nucleotide polymorphisms (SNPs) in three regions of cases were higher than those in the control (P<10⁻⁴). The authors then tested two independent replication sets for strong association 6 SNPs in 349 pairs of case-control drivers using the U.S. ABI 3730 sequencing method. The results indicated that SNP rs6069499 within linked CBLN4 gene are strongly associated with accident proneness (P_combined=6.37×10⁻¹⁰). According to CBLN4 gene mainly involved in adrenal development and the regulation of secretion, the authors performed 12 biochemical parameters of the blood using radioimmunoassay. The levels of dopamine (DA) and adrenocorticotropic (ACTH) hormone showed significant differences between accident-prone drivers and safe drivers (P_DA=0.03, P_ACTH=0.01). It is suggested that the accident-prone drivers may have the idiosyncrasy of susceptibility.     

Effects of β-Phenylethylamine on Psychomotor,Rewarding, and Reinforcing Behaviors and Affective State: The Role of Dopamine D1 Receptors

Beta-phenylethylamine (β-PEA) is a well-known and widespread endogenous neuroactive trace amine found throughout the central nervous system in humans. In this study, we demonstrated the effects of β-PEA on psychomotor, rewarding, and reinforcing behaviors and affective state using the open-field test, conditioned place preference (CPP), self-administration, and ultrasonic vocalizations (USVs) paradigms. We also investigated the role of the dopamine (DA) D1 receptor in the behavioral effects of β-PEA in rodents. Using enzyme-linked immunosorbent assay (ELISA) and Western immunoblotting, we also determined the DA concentration and the DA-related protein levels in the dorsal striatum of mice administered with acute β-PEA. The results showed that acute β-PEA increased stereotypic behaviors such as circling and head-twitching responses in mice. In the CPP experiment, β-PEA increased place preference in mice. In the self-administration test, β-PEA significantly enhanced self-administration during a 2 h session under fixed ratio (FR) schedules (FR1 and FR3) and produced a higher breakpoint during a 6 h session under progressive ratio schedules of reinforcement in rats. In addition, acute β-PEA increased 50-kHz USV calls in rats. Furthermore, acute β-PEA administration increased DA concentration and p-DAT and TH expression in the dorsal striatum of mice. Finally, pretreatment with SCH23390, a DA D1 receptor antagonist, attenuated β-PEA-induced circling behavior and β-PEA-taking behavior in rodents. Taken together, these findings suggest that β-PEA has rewarding and reinforcing effects and psychoactive properties, which induce psychomotor behaviors and a positive affective state by activating the DA D1 receptor in the dorsal striatum.     

The role of learned irrelevance in attentional set-shifting impairments in Parkinson's disease.

In this study, the cognitive and neurochemical factors underlying learned irrelevance, one of the mechanisms thought to be responsible for attentional set-shifting deficits in Parkinson's disease (PD), were investigated. In a visual discrimination learning task, the extent to which a target dimension was irrelevant prior to an extra-dimensional shift was varied. Twenty patients with PD and 22 healthy participants performed the task twice, with patients tested on and off L-dopa. The patients made more errors than control participants in the condition in which the target dimension was completely irrelevant prior to the extradimensional shift, but not when it was partially reinforced. Moreover, L-dopa had no effect on the patients' task performance, despite improving their working memory. These results confirm that learned irrelevance is a significant factor in accounting for attentional set-shifting deficits in patients with PD, although unlike other executive impairments in this group, the phenomenon appears to be unrelated to their central dopaminergic deficit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biological implementation of the temporal difference algorithm for reinforcement learning: Theoretical comment on O'Reilly et al. (2007).

The ability to survive in the world depends critically on the brain's capacity to detect earlier and earlier predictors of reward or punishment. The dominant theoretical perspective for understanding this capacity has been the temporal difference (TD) algorithm for reinforcement learning. In this issue of Behavioral Neuroscience, R. C. O'Reilly, M. J. Frank, T. E. Hazy, and B. Watz (2007, see record 2007-02025-004)) propose a new model dubbed primary value and learned value (PVLV) that is simpler than TD, and they claimed that it is biologically more realistic. In this commentary, the author suggests some slight modifications of a previous biological implementation of TD instead of adopting the new PVLV algorithm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence That GABA Mediates Dopaminergic and Serotonergic Pathways Associated With Locomotor Activity in Juvenile Chinook Salmon (Oncorhynchus tshawytscha).

The authors examined the control of locomotor activity in juvenile salmon (Oncorhynchus tshawytscha) by manipulating 3 neurotransmitter systems--gamma-amino-n-butyric acid (GABA), dopamine, and serotonin--as well as the neuropeptide corticotropin releasing hormone (CRH). Intracerebroventricular (ICV) injections of CRH and the GABAA agonist muscimol stimulated locomotor activity. The effect of muscimol was attenuated by administration of a dopamine receptor antagonist, haloperidol. Conversely, the administration of a dopamine uptake inhibitor (4′,4″-difluoro-3-alpha-[diphenylmethoxy] tropane hydrochloride [DUI]) potentiated the effect of muscimol. They found no evidence that CRH-induced hyperactivity is mediated by dopaminergic systems following concurrent injections of haloperidol or DUI with CRH. Administration of muscimol either had no effect or attenuated the locomotor response to concurrent injections of CRH and fluoxetine, whereas the GABAA antagonist bicuculline methiodide potentiated the effect of CRH and fluoxetine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Compound Measure of Hand-Foot-Eye Preference Masked Opposite Turning Behavior in Healthy Right-Handers and Non-Right-Handers: Technical Comment on Mohr et al. (2003).

A previous article reported opposite turning behavior in right-handers and non-right-handers (C. Mohr. T. Landis, H. S. Bracha, & P. Brugger, 2003; see record 2003-10460-031). This observation appears contradictory to the 1st study on long-term spontaneous turning behavior in healthy participants (H. S. Bracha, D. J. Seitz, J. Otemaa, & S. D. Click, 1987; see record 1987-33604-001). These latter authors found a complex interaction between hemispheric dominance, preferred turning side, and sex. C. Mohr et al. (2003) argued that the differentiation of the population in hemisphere-dominant groups by a compound measure of hand-foot-eye preference might have masked their recent finding. Thus, this commentary presents a reanalysis of the original data set (H. S. Bracha et al., 1987). Replicating recent observation, right-handers preferred left-sided turns; and non-righthanders, right-sided turns. This replication strengthens the proposition that handedness and turning behavior might depend on interhemispheric dopamine asymmetries. (PsycINFO Database Record (c) 2010 APA, all rights reserved)