Baclofen antagonism by 2-hydroxy-saclofen in the cat spinal cord

When administered microelectrophoretically, a sulphonic acid derivative of baclofen, 3-amino-2-(4-chlorophenyl)-2-hydroxy-propylsulphonic acid, reversibly reduced the presynaptic reduction by (−)-baclofen of the monosynaptic excitation of spinal interneurones by impulses in low threshold primary afferent fibres of the cat as well as the postsynaptic depression by (−)-baclofen of the firing of these neurones. This compound, 2-hydroxy-saclofen, may be useful in assessing the physiological significance of central baclofen receptors.