I have Potter & Perry for Nursing Fundamentals and in the chapter "comfort" or about pain, it either has conflicting information, or I am not understanding it all. What is the difference between a Neuromodulator and a Neurotransmitter and why would it say that bradykinin is an excitatory neurotransmitter and then in a box say that it is an inhibitory neuromodulator. I went googling my butt off and now I'm so lost. I've read that neurotransmitters cannot be neuromodulators and then I've read the opposite. My final exam is in a few days, I guess I want to know the Potter & Perry answer if anyone has it, because that's what will be on the exam....and then if someone knows how it really is....please help me understand it...the real way. Thanks guys!