<unk>  are released from the pituitary gland, typically in response to pain, and can act in both the central nervous system (CNS) and the peripheral nervous system (PNS). In the PNS, β-endorphin is the primary<unk> released from the pituitary gland.<unk>  inhibit transmission of pain signals by binding μ-receptors of peripheral nerves, which block their release of neurotransmitter substance P. The mechanism in the CNS is similar but works by blocking a different neurotransmitter: gamma-aminobutyric acid (GABA). In turn, inhibition of GABA increases the production and release of dopamine, a neurotransmitter associated with reward learning.
Endorphins
Serotonin
N-Acetylserotonin
Opioid peptide
Gluten exorphin
Neuropeptide
Dynorphin
Beta-Endorphin