Tracazolate (ICI 136753) hydrochloride is a potent GABAA receptor modulator. Tracazolate hydrochloride has selectivity for β3 and potentiates α1β1γ2s (EC50=13.2 μM), α1β3γ2 (EC50=1.5 μM). Tracazolate hydrochloride has the potency (EC50) determined by the nature of the third subunit (γ1-3, δ, ε) within the receptor complex. Tracazolate hydrochloride possesses anxiolytic and anticonvulsant activity[2].IC50 & Target: GABAAIn Vitro: Tracazolate (ICI 136753) hydrochloride inhibits α1β1ε (EC50=4.0 μM) and α1β3ε (EC50=1.2 μM), α1β3 (EC50=2.7 μM) and α6β3γ (EC50=1.1 μM). Replacement of Ser265 within the β1 subunit with Asn (the β3 counterpart) increases the sensitivity of tracazolate, whereas the opposite mutation (Asnβ3 to Ser) decreases the sensitivity to Tracazolate. Tracazolate hydrochloride interacts with γ-aminobutyric acid GABAA receptors, adenosinereceptors, and phosphodiesterases.
Tracazolate hydrochloride (10?μM) increases the maximum current amplitude and enhances the sensitivity of α1β2δ-containing GABAA receptors in oocytes[2].