Alpha Adrenergic Pathway

Memory Hack💡

Similar to “alpha”, Q comes before S in the alphabet. This hack can help you remember that "alpha" adergenic uses Gaq rather than Gas

Notes

• Once activated, the alpha subunit Gaq activates phospholipase C (PLC)

• Phospholipase C cleaves PIP2 to become TWO second messengers→ IP3 and DAG

• IP3 is no longer stuck in the membrane, and it travels to and binds the receptor on a calcium ion channel which floods calcium into the cell. 

• DAG is still stuck in the membrane, so it travels along it and binds to protein kinase C (PKC), which is also waiting for the calcium ion.

→ Once they both bind, it results in smooth muscle contraction, limiting blood flow to these organs. 

Conceptually: if we are in fight or flight, we want to stop focusing energy on our digestive system, which is part of why blood flow gets limited. Also, it allows us to oxygenate more blood to provide more energy!