H₂ receptors are positively coupled to adenylate cyclase via G_s. It is a potent stimulant of cAMP production, which leads to activation of Protein Kinase A. PKA functions to phosphorylate certain proteins, affecting their activity. The drug betazole is an example of a Histamine H₂ receptor agonist.

H₂ receptors are positively coupled to adenylate cyclase via G_s. It is a potent stimulant of cAMP production, which leads to activation of Protein Kinase A. PKA functions to phosphorylate certain proteins, affecting their activity. The drug betazole is an example of a Histamine H₂ receptor agonist.