Could anyone direct me to some article/book/paper on neuropeptides? Any information is appreciated, I just want to know about them. What is their activity in the body? I have heard (note: heard, not read) that they travel throughout the body...but I can't see what they would do, or what effect they could have. After all, there are no axon terminals in the cells permeating the body (except motor cells, I guess), so I don't see how they could be important facets of any normal process. However, I have heard of people talking about them as though they represent a relation between emotion and health; as well as many other, similar claims.
Again, I pretty much don't know anything about them (accept that they are a sort of neurotransmitter which seems to travel throughout the body, instead of just within synapses), so I'll appreciate any information I can get.