3-Aminopropylphosphonic Acid

3-Aminopropylphosphonic acid (3-APPA) is a phosphonic analog of GABA that acts as a partial agonist of GABAB receptors (IC50 = 1.5 ?M in a radioligand binding assay).{36477,23832} It induces relaxation in unstimulated isolated guinea pig ileum longitudinal muscle and reverses GABA- and baclofen-induced inhibition of twitch responses in isolated guinea pig ileum longitudinal muscle.{36477} 3-APPA (5 mg/kg) completely inhibits GABA- and baclofen-induced inhibition of vagally stimulated bronchospasms in guinea pigs.{36478} It also reverses the antitussive effect of baclofen in cats when administered at a dose of 3 mg/kg.{36479}