Comparing Addiction’s / Comparing Pain’s

Compare and contrast nicotine and alcohol addictions. For this discussion, emphasize the mechanism of action, receptors and any pathways involved.
Compare and contrast stimulant and opioid addictions. For this discussion, emphasize the mechanism of action, receptors and any pathways involved.
Compare and contrast "normal" pain and neuropathic pain. For this discussion, include how the differences impact treatment.