Journal of the neurological Sciences 199 Elsevier Publishing Company, Amsterdam Printed in The Netherlands The Action of a GABA Derivative in Human Spasticity D. BURKE*, C. J. ANDREWS** AND L. KNOWLES*** Dirision ~1' Neurology, The Pr&ce Hen O, Hospital and the School of Medicine, Unirersio' of" New South Wales, Sydney ( Australia ) (Received 17 January, 1971) INTRODUCTION Neutral amino acids such as glycine and ?,-aminobutyric acid (GABA) have been shown to have an inhibitory action on spinal neurones, producing membrane hyper- polarisation similar to the actions of naturally occurring inhibitory transmitters (Curtis et al. 1968b). The possibility of a therapeutic role of these amino acids or their derivatives has therefore been investigated in disorders of muscle tone. A derivative of 7-aminobutyric acid, viz. fl-(4-chlorophenyl)-7-aminobutyric acid, designated 34,647-Ba, has been shown in a preliminary controlled trial to be an effective agent in alleviating spasticity caused by spinal cord lesions (Jones et al. 1970). It is therefore of interest to analyse the effects of this drug in spastic subjects, since presumably it mimics the inhibitory action of its parent substance. MATERIALS AND METHODS Electromyographic assessment was carried out before and during treatment in 10 patients with clinically stable spasticity, all of whom had responded satisfactorily to 34,647-Ba. Seven patients were quadripleg:c as a result of trauma to the cervical spinal cord, the lesion being clinically complete in 2. One patient suffered from multiple sclerosis and 1 from transverse myelitis. One patient had a complete spinal cord lesion, confirmed at laminectomy, due to an angioma of the thoracic cord. Four of the 10 patients had taken part in the double-blind trial (Jones et al. 1970). Control observations were made before starting oral treatment with 34,647-Ba and comparable observations were made at least 4 days after reaching the optimal dosage for each patient as judged clinically. This dosage varied from 60 to 90 mg/day, admin- istered in 3 divided doses, 1 In~ proJeCt was supported by grants from the National Health and Medical Research Council of Australia, the Adolph Basser Trust, and Mr. and Mrs. Edwin Street. * Commonwealth Postgraduate Scholar and Adolph Basser Research Fellow in Neurology. ** Edwin and Daisy Street Research Fellow in Neurology. *** Research Assistant of the National Health and Medical Research Council of Australia. J. neurol. Sci., 1971, 14:199-208