Final answer:
Adrenaline induces long term gene expression response through GCPR-PKA signaling by activating ß-adrenergic receptors in muscle cells, leading to an increase in cAMP and subsequent activation of PKA. PKA then phosphorylates enzymes involved in glycogen metabolism, promoting glycogen degradation and inhibiting glycogen synthesis, allowing the muscle cell to obtain glucose for energy use.
Step-by-step explanation:
When adrenaline binds to ß-adrenergic receptors in muscle cells, it triggers a signaling pathway that leads to the activation of cyclic AMP (cAMP) inside the cell. This increase in cAMP activates protein kinase A (PKA), which then phosphorylates two enzymes. The first enzyme, glycogen phosphorylase (GP), promotes the degradation of glycogen into glucose.
The second enzyme, glycogen synthase (GS), is inhibited by phosphorylation, preventing glycogen formation from glucose. These changes enable the muscle cell to quickly convert stored glycogen into glucose and make it available for energy use in response to a surge of adrenaline, such as in the 'fight or flight' response.