Animal studies have emphasized the role of phasic dopamine (DA) signaling in reward-related learning, but these processes remain largely unexplored in humans.
Objectives To evaluate the effect of a single, low dose of a D2/D3 agonist-pramipexole-on reinforcement learning in healthy adults. Based on prior evidence indicating that low doses of DA agonists decrease Transmembrane Transporters inhibitor phasic DA release through autoreceptor stimulation, we hypothesized that 0.5 mg of pramipexole would impair reward learning due to presynaptic mechanisms.
Materials and methods Using a double-blind design, a single 0.5-mg
dose of pramipexole or placebo was administered to 32 healthy volunteers, who performed a probabilistic reward task involving a differential reinforcement schedule as well as various control tasks.
Results As hypothesized, response bias toward the more frequently rewarded stimulus was impaired in the pramipexole group, even
after adjusting for transient adverse effects. In addition, the pramipexole group showed reaction time and motor speed slowing and increased negative affect; however, when adverse physical side effects were considered, group differences in motor speed and negative affect disappeared.
Conclusions These findings show that a single low dose of pramipexole impaired the acquisition of reward-related behavior in healthy participants, and they are consistent with prior evidence suggesting that phasic DA signaling is required to reinforce actions leading to reward.
The potential Tariquidar concentration implications of the present findings to psychiatric conditions, including depression and impulse control disorders related to addiction, are discussed.”
“Primarily outside the scientific community, misapprehensions and misinformation about recombinant DNA-modified (also known as ‘genetically modified’, or ‘GM’) plants have generated significant ‘pseudo-controversy’ over their safety that has resulted in unscientific and excessive regulation (with attendant inflated development costs) and disappointing progress. Alectinib in vivo But pseudo-controversy and sensational claims have originated within the scientific community as well, and even scholarly journals’ treatment of the subject has been at times unscientific, one-sided and irresponsible. These shortcomings have helped to perpetuate ‘The Big Lie’ – that recombinant DNA technology applied to agriculture and food production is unproven, unsafe, untested, unregulated and unwanted. Those misconceptions, in turn, have given rise to unwarranted opposition and tortuous, distorted public policy.”
“Both clinical investigations and studies with animals reveal nuclei within the diencephalon that are vital for recognition memory (the judgment of prior occurrence). This review seeks to identify these nuclei and to consider why they might be important for recognition memory.