850608-87-6

Sodium channel IC50: 43 μM (GABA receptor)

Riluzole hydrochloride is an anticonvulsant drug and belongs to the family of use-dependent Na ⁺ channel blocker which can also inhibit GABA uptake with an IC ₅₀ of 43 μM. At 20 μM, Riluzole hydrochloride inhibits peak autaptic IPSCs only slightly but prolongs IPSCs reliably. It is also found that Riluzole hydrochloride causes a strong, concentration-dependent, readily reversible enhancement of responses to 2 μM GABA. At higher concentrations of Riluzole hydrochloride, especially 300 μM, GABA currents exhibit apparent desensitization during prolonged co-exposure to 2 μM GABA and Riluzole hydrochloride. The EC ₅₀ of Riluzole hydrochloride potentiation of GABA responses is about 60 μM.

In normal naïve rats, systemic injection of Riluzole hydrochloride (8 mg/kg, i.p.; n=6 rats) decreases the duration of ultrasonic but not audible vocalizations evoked by noxious stimulation of the knee joint compare to vehicle tested in the same rats (P<0.05). Systemic application of Riluzole hydrochloride (8 mg/kg, i.p.; n=19 rats) decreases the vocalizations of arthritic rats compare to predrug and vehicle significantly (P<0.05 to 0.001). Riluzole hydrochloride administered into the CeA significantly decreases the duration of audible and ultrasonic vocalizations evoked by noxious stimulation of the knee compare to predrug values (n=8 rats; P<0.05 to 0.01).