Antagonism of inhibitory amino acids by the steroid derivative RU5135

Abstract

The steroid derivative RU5135 has been tested for its ability to antagonize glycine and the γ‐aminobutyric acid (GABA) analogue muscimol on isolated preparations of rat optic nerve and cuneate nucleus, respectively. On the cuneate nucleus, RU5135 antagonized muscimol in a competitive manner with a pA2 value of 8.31. RU5135 shared a common site of action with bicuculline that was separate from the Picrotoxin site. On the optic nerve, RU5135 antagonized glycine with a pA2 of 7.67. It shared a common site of action with strychnine. 1985 British Pharmacological Society