Which type of messenger increases after activation of D1 receptors?

Upon activation of D1 receptors, the intracellular messenger that increases is cyclic adenosine monophosphate (cAMP). D1 receptors are a subtype of dopamine receptors that are linked to the stimulatory G protein (Gs). When dopamine binds to D1 receptors, this activation stimulates adenylate cyclase, the enzyme responsible for the conversion of ATP to cAMP.

The increase in cAMP acts as a secondary messenger that mediates various physiological responses, including neuronal signaling and smooth muscle relaxation. This mechanism is crucial in many central nervous system processes and in the regulation of renal blood flow, among other functions.

In contrast, the other messengers listed serve different roles in cellular signaling:

• cGMP is primarily involved in signaling pathways associated with nitric oxide and certain natriuretic peptides.

• Diacylglycerol (DAG) and inositol trisphosphate (IP3) are both related to the activation of phospholipase C and are involved in pathways associated with G protein-coupled receptors that activate Gq proteins, leading to calcium mobilization and muscle contraction or secretion events, which is distinct from the mechanism associated with D1 receptor activation.

Thus, the identifying feature of D1 receptors is their