Final answer:
The sympathetic nervous system, norepinephrine, beta-adrenergic receptors, GPCRs, and cAMP are crucial in regulating the body's stress response and metabolic activities. They work together to ready the body for a fight-or-flight response through a cascade of signaling events that lead to various physiological changes.
Step-by-step explanation:
The sympathetic nervous system, norepinephrine, beta-adrenergic receptors, G-protein-coupled receptors (GPCRs), and cyclic adenosine monophosphate (cAMP) all play integral roles in the regulation of stress response and metabolic activities, which matches with Option 3. When the sympathetic nervous system is activated by stressful stimuli, signaling molecules such as norepinephrine and epinephrine are released, which bind to beta-adrenergic receptors. This binding activates a G-protein, which in turn triggers adenylyl cyclase to convert ATP into cAMP, a secondary messenger responsible for mediating specific cellular responses.
cAMP activation leads to various physiological effects such as increased heart rate, dilated airways, enhanced blood flow to muscles, and elevated blood glucose levels. These responses collectively prepare the body for the 'fight-or-flight' reaction. Sympathomimetic drugs can mimic these effects by stimulating adrenergic receptors, while sympatholytic drugs block them, moderating the sympathetic system's response.