... state. Opioid receptors presynaptically inhibit transmission of excitatory pathways. These pathways include acetylcholine, the catecholamines, serotonin, and substance P. Substance P is a neuropeptide active in neurons that mediate our sense of pain; antagonists of substance P are currently under investigation as clinical antidepres! sants. Endorphins are also involved in glucose regulation. Opioid receptors are functionally designated as mu, delta, kappa, etc. These categories can ... ...

• Word Count: 3024
• Approx Pages: 12
• Grade Level: Undergraduate