Proenkephalin-A (PENK)

Met- and Leu-enkephalins compete with and mimic the effects of opiate drugs. They play a part in several of physiologic functions, including pain perception and responses to stress.

PENK(114-133) and PENK(237-258) increase glutamate release in the striatum. PENK(114-133) reduces GABA concentration in the striatum.