A crucial role for cAMP and protein kinase A in D1 dopamine receptor regulated intracellular calcium transients.

D1-like dopamine receptors stimulate Ca(2+) transients in neurons but the effector coupling and signaling mechanisms underlying these responses have not been elucidated. Here we investigated potential mechanisms using both HEK 293 cells that stably express D1 receptors (D1HEK293) and hippocampal neurons in culture. In D1HEK293 cells, the full D1 receptor agonist SKF 81297 evoked a robust dose-dependent increase in Ca(2+)(i) following 'priming' of endogenous G(q/11)-coupled muscarinic or purinergic receptors.

Regular transfusion lowers plasma free hemoglobin in children with sickle-cell disease at risk for stroke.

Background And Purpose: Intravascular hemolysis releases large amounts of free hemoglobin (PFH) in plasma of sickle-cell disease (SCD) patients. PFH has been associated with harmful endothelial actions including scavenging nitric oxide (NO). Whether PFH plays a role in stroke in SCD has not been examined.

D1/D5 dopamine receptors stimulate intracellular calcium release in primary cultures of neocortical and hippocampal neurons.

D1/D5 dopamine receptors in basal ganglia, hippocampus, and cerebral cortex modulate motor, reward, and cognitive behavior. Previous work with recombinant proteins revealed that in cells primed with heterologous G(q/11)-coupled G-protein-coupled receptor (GPCR) agonists, the typically G(s)-linked D1/D5 receptors can stimulate robust release of calcium from internal stores when coexpressed with calcyon. To learn more about the intracellular signaling mechanisms underlying these D1/D5 receptor regulated behaviors, we explored the possibility that endogenous receptors stimulate internal release of calcium in neurons.