The thio analogues of the GABA (y-aminobutyric acid) agonist THIP (4, 5, 6, 7- tetrahydroisoxazolo [5, 4-c] pyridin-3-01), the GABA uptake inhibitor THPO (4, 5, 6, 7- tetrahydroisoxazolo [4, 5-c] pyridin-3-01), and the glycine antagonist THAZ (5, 6, 7, 8- tetrahydro-4H-isoxazolo [4, 5-d] azepin-3-ol) have been synthesized and tested biologically on single neurons in the cat spinal cord and in vitro by using synaptic membrane ...