Final answer:
Animal research has revealed c. dopamine as the neurotransmitter linked to the brain's reward system. After dopamine binds to its receptor, there is typically an increase in cAMP concentration. Dopamine and cAMP are both integral to reward system functioning.
Step-by-step explanation:
Animal research has identified a general reward system in the brain involving the release of the neurotransmitter dopamine. This neurotransmitter plays a crucial role in reward, motivation, and addiction-related behaviors. Dopamine binds to G-protein-linked receptors, which typically leads to an increase in the concentration of cyclic adenosine monophosphate (cAMP), as depicted in Figure 37.6 and Figure 28.6.
When dopamine binds to its receptor, it activates a G-protein. This in turn activates adenylyl cyclase which converts ATP to cAMP. Thus, after dopamine binds its receptor, you would expect the concentration of cAMP to increase. Epinephrine and norepinephrine are also part of the adrenergic system. They can function as hormones when released into the bloodstream, but they are not specifically associated with the brain's reward system as dopamine is.