Effects of protein kinase A inhibitor and activator on rewarding effects of SKF-82958 microinjected into nucleus accumbens shell of ad libitum fed and food-restricted rats

Enhanced Pain Sensitization Induced by Chronic Sleep Deprivation: The Role of Dopamine D2 Receptors-Dependent Homer1a Protein

Numerous studies have demonstrated a positive correlation between sleep disorders and hyperalgesia. These sleep disorders adversely affect the descending pain regulatory system. Researchers have extensively studied the midbrain dopamine system in relation to pain associated with sleep disturbances. Our study shows that chronic sleep deprivation decreases dopamine responses to noxious stimuli within the mouse nucleus accumbens, regulated by dopamine release and intracellular signals. Furthermore, we confirmed that the dopamine D2 receptors play a critical role in the pain associated with chronic sleep deprivation. Importantly, we revealed that homer1a in D2 receptor neurons enhances AMPA receptors expression.

SKF82958, a dopamine D1 receptor agonist, disrupts prepulse inhibition in the medial prefrontal cortex and nucleus accumbens in C57BL/6J mice

Prepulse inhibition (PPI) is a crucial indicator of sensorimotor gating that is often impaired in neuropsychiatric diseases. Although dopamine D1 receptor agonists have been found to disrupt PPI in mice, the underlying mechanisms are not fully understood. In this study, we aimed to identify the brain regions responsible for the PPI-disruptive effect of the D1 agonist in mice. Results demonstrated that intraperitoneal administration of the selective dopamine D1 receptor agonist SKF82958 dramatically inhibited PPI, while the dopamine D1 receptor antagonist SCH23390 enhanced PPI. Additionally, local infusion of SKF82958 into the nucleus accumbens and medial prefrontal cortex disrupted PPI, but not in the ventral hippocampus. Infusion of SCH23390 into these brain regions also failed to enhance PPI. Overall, the study suggests that the nucleus accumbens and medial prefrontal cortex are responsible for the PPI-disruptive effect of dopamine D1 receptor agonists. These findings provide essential insights into the cellular and neural circuit mechanisms underlying the disruptive effects of dopamine D1 receptor agonists on PPI and may contribute to the development of novel treatments for neuropsychiatric diseases.