inosine-triphosphate and gaboxadol

The influence of gamma-aminobutyric acid (GABA) receptor agonists and antagonists on the intracellular concentration of inositol 1,4,5-triphosphate (IP3) was examined in neuronal cultures of embryonic chick tectum. GABA and selective agonists of its receptors were inactive, whereas phaclofen, a GABA-B receptor antagonist, increased IP3 levels in a concentration-dependent manner. This effect occurred at phaclofen concentrations much lower than those required to affect GABA-B receptors. It is concluded that phaclofen, in addition to its known effect at GABA-B receptors, is also active at an as-yet undefined site.

Topics: Animals; Baclofen; Chick Embryo; gamma-Aminobutyric Acid; Inosine Nucleotides; Inosine Triphosphate; Isoxazoles; Neurons; Receptors, GABA-A; Superior Colliculi