Which of the following is NOT a chemical associated with pain found around trigger points?

Dopamine is known primarily as a neurotransmitter involved in a variety of brain functions, such as mood regulation, reward, and motor control. In the context of pain and trigger points, dopamine is not typically associated with the inflammatory processes or pain signaling pathways that characterize the chemical environment around trigger points.

In contrast, Interleukin 1, histamines, and substance P are all substances well-documented in relation to inflammation and pain. Interleukin 1 is a cytokine that plays a crucial role in the inflammatory response, often increasing sensitivity to pain. Histamines are involved in the body’s immune response and can contribute to pain and inflammation as well. Substance P is a neuropeptide that is directly linked to the transmission of pain signals in the nervous system.

Thus, recognizing dopamine's primary role in other physiological processes helps distinguish it from the other listed chemicals that are directly associated with pain mechanisms around trigger points.