BACKGROUND Dopaminergic and opioidergic drugs have been found to be effective in patients with restless legs syndrome (RLS). OBJECTIVES To test the effect of apomorphine--a combined opioidergic and dopaminergic agonist--and subsequent selective antagonism by naloxone and metoclopramide on subjective and objective symptoms in patients with idiopathic RLS. METHODS Nine patients with RLS were ...

Many fearful expectations are shaped by observation of aversive outcomes to others. Yet, the neurochemistry regulating social learning is unknown. Previous research has shown that during direct (Pavlovian) threat learning, information about personally experienced outcomes is regulated by the release of endogenous opioids, and activity within the amygdala and periaqueductal gray (PAG). Here we r...

Ferulic acid is a caffeic acid derivative and a common phenolic compound quite abundant in various medicinal plants that used for pain relief. The antinociceptive effect of ferulic acid has been shown; however, the action mechanisms of ferulic acid still remain unclear. The purpose of the present study was to investigate the possible mechanism of action of ferulic acid-induced antinociception i...

Antidepressant drugs, especially tricyclics have been widely used in the treatment of chronic pain, but not in acute pain. Because of numerous undesirable side effects, the selective serotonin reuptake inhibitors (SSRIs), with their favorable side effect profile, are preferred nowadays. An activation of the endogenous opioid mechanisms or potentiation of the analgesic effect mediated by seroton...

Ferulic acid is a caffeic acid derivative and a common phenolic compound quite abundant in various medicinal plants that used for pain relief. The antinociceptive effect of ferulic acid has been shown; however, the action mechanisms of ferulic acid still remain unclear. The purpose of the present study was to investigate the possible mechanism of action of ferulic acid-induced antinociception i...

Background and Objective: It has been shown that the opioidergic system exerts widespread effects on cognitive functions. Interactions between opioid and serotonin receptors have been reported in some brain structures such as the dorsal hippocampus, thus a functional interaction between opioids and serotonin seems possible concerning memory control. The purpose of this study was to assess the e...

Endogenous opiate peptides can regulate neuroendocrine and circulatory responses to behavioral stress and may be important in the pathogenic effects of sympathoadrenal reactivity. We tested this hypothesis by examining the effect of the opiate antagonist naloxone on blood pressure responses to behavioral stress in young adults with high, medium, or low casual blood pressures. Naloxone increased...