And so this is called our secondary messenger. And the secondary messenger, our cyclic Amp goes on and activates protein kinase A. So that now protein kinase A can go on and phosphorylate other enzymes inside our cell. So this is one specific example of a secondary messenger pathway. This is the pathway by which we pass down signals from one cell to a different cell in the body. So in this case we only had one intermediate molecule involved, the neurotransmitter.