It is an orally active muscle relaxant and is used in treating the spasticity and muscle
rigidity of spinal cord injuries, cerebral palsy, and other related neurologic disorders.
4.7.4 GABA Receptors: Postsynaptic Drug Effects4.7.4.1 GABA Agonists
Directly acting GABA agonists usually bear some resemblance to the neurotransmitter.
Muscimol (4.172), an isoxazole isolated from the mushroom Amanita muscaria
(“deadly fly agaric”), is a hallucinogen with a receptor affinity greater than that of
GABA (0.9 nM versus 9.4 nM on Triton-treated membranes) on the GABABreceptor.
A number of related compounds have been synthesized and have also proved to be
active, among them THIP (gaboxadol) (4.173). Progabide (4.174) is another novel
GABA agonist that bears a resemblance to the benzodiazepines.
NEUROTRANSMITTERS AND THEIR RECEPTORS 273