Which neurotransmitters act as endogenous opioids found mainly in the pituitary gland?

Endorphins are a group of neurotransmitters that act as endogenous opioids, primarily produced in the pituitary gland and the central nervous system. They play a crucial role in pain relief, mood regulation, and the body's response to stress. Endorphins bind to opioid receptors in the brain, mimicking the effects of externally administered opiates, thereby reducing the perception of pain and enhancing feelings of well-being.

The presence of endorphins in the pituitary gland highlights their importance in the neuroendocrine system, where they can influence various physiological processes through hormone release. Their function goes well beyond mere neurotransmission, impacting overall emotional and physical health.

In contrast, other options do not have the same characteristics; for instance, Substance P is specifically involved in pain transmission rather than acting as an endogenous opioid. Norepinephrine plays a crucial role in attention and responding actions, while acetylcholine is primarily involved in muscle activation and other neural signaling. Each of these neurotransmitters has distinct functions that do not align with the opioid action attributed to endorphins.