Final answer:
Dopamine is the neurotransmitter responsible for many functions of the frontal lobe, playing key roles in memory, attention, and problem-solving, with an increase in cAMP observed after dopamine receptor binding.
Step-by-step explanation:
The neurotransmitter responsible for many functions of the frontal lobe is dopamine. This neurotransmitter is involved in a range of functions including cognition, affective and behavioral responses. Dopamine operates within the brain's reward and limbic systems, significantly affecting memory, attention, and problem-solving. Dopaminergic pathways, including the mesocorticolimbic system, are crucial in the prefrontal cortex (PFC) where they regulate cognitive functions and responses to stressors.
After dopamine binds to its receptor, which is G-protein-linked, you can expect an increase in the concentration of cAMP (cyclic adenosine monophosphate), as it is a secondary messenger that gets activated when dopamine stimulates the receptor. Contrarily, before phosphorylation of tyrosine residues occurs, the hormone insulin binds to a receptor tyrosine kinase on the surface of target cells.