“A 30 ….1 mM CuCl2 suppressed responses to single concentrations of the following …-proline, D-tryptophan, 6-chloro-D-tryptophan, L-valine , glycine, sucrose, maltose, lactose, tetrachloro-galacto-sucrose, glucose, fructose, methyl alpha-D-glucopyranoside, glycerol, …-4'-cyano-3'-(2-2-2-trifluoro acetamido)succinanilic acid, phenethyurea, and stevioside.”