TPMPA is a GABA_A-Ρ1 (Ρ1 GABA_C) receptor antagonist that is 8-fold selective for GABA_A-Ρ1 over GABA_A-Ρ2 (Ρ2 GABA_C) receptors expressed inX. laevisoocytes (K_bs = 2 and 16 μM, respectively).¹In rat hippocampal slices, TPMPA blocks the inhibitory effect of the GABA_Bagonist 3-APMPA on excitatory postsynaptic currents (EPSCs) with an EC₅₀value of 490 μM.²TPMPA (100 μM) increases light sensitivity and the maximal response of rat retinal ganglion cells without altering their dynamic range.³In sleeping rats, TPMPA (50 μg, i.c.v.) increases waking from 45 to 62% compared to a vehicle control and decreases slow-wave and paradoxical sleep (REM) by 11 and 5.4%, respectively.⁴

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