gamma-aminobutyric acid ( gaba , half-maximal inhibitory concentration , ic50 = 9.9 microm ) and ( - ) -baclofen ( ic50 = 4.5 microm ) but not 10 ( -4 ) m muscimol , exerted a presynaptic inhibitory effect on cholinergic transmission in field-stimulated guinea-pig taenia coli preparations , in vitro .
C0016904
gaba
C0004609
baclofen