In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.

Q: Ergovaline binding and activation of D2 dopamine receptors in GH4ZR7 cells.

A: dopamine
****
Q: Isolation and function of the amino acid transporter PAT1 (slc36a1) from rabbit and discrimination between transport via PAT1 and system IMINO in renal brush-border membrane vesicles.

A: amino acid
****
Q: Studies on an (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor antagonist IKM-159: asymmetric synthesis, neuroactivity, and structural characterization.

A:
(S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid
****