Originally Posted by Tristar
Does morphine stimulate opioid receptors to secrete endorphins that will inihibit Substance P?
As stated above opioids bind to opioid receptor sites, in morphine's case mu receptors (1 and 2). Morphine mimics endorphins and inhibits the release of several neurotransmitters including Substance P and acetycholine. Morphine acts mainly on the presynaptic nerve terminal.
By the way this doesn't sound like a typical undergraduate nursing topic...