β-Endorphin (rat)

β-Endorphin (β-EP) is an endogenous opioid neuropeptide with diverse biological activities. It is produced via piomelanocortin cleavage in the pituitary gland, hypothalamus, and in lymphocytes, then migrates to its sites of action which include plasma, gut, skin, placenta, cerebrospinal fluid, and cardiac tissues. β-EP induces concentration-dependent decreases in electrically stimulated contraction of the mouse vas deferens that can be reversed by the μ-opioid antagonist CTP and δ-opioid antagonist ICI 174,864.

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