Br-PBTC is a highly potent, 2/4 subtype-selective positive allosteric modulator of nicotinic acetylcholine receptors (nAChRs). It specifically targets α2β2, α2β4, α4β2, α4β4, (α4β2)2α4, and (α4β2)2β2 subtypes of nAChRs, with EC50 values ranging from 0.1 to 0.6 μM. Br-PBTC exerts its activity by binding to the c-tail region of an α subunit.

Br-PBTC (0.01~10 μM; HEK cells) selectively affects 2 and 4 subunits. Br-PBTC (3 μM; oocytes) has greater effects on nAChRs with 2 subunits over those with 4 subunits. Br-PBTC (0.01~10 μM; 15 minutes; HEK cells) can increase channel activation by a maximal concentration of ACh. Br-PBTC (3 μM; 50 seconds; oocytes) increased ACh activation of α4β2 nAChRs by 385± 61 %. Br-PBTC (3 μM；oocytes) reactivates short term desensitized nAChRs expressed. Br-PBTC (3 μM; 500 seconds; HEK cells) reactivates short term desensitized (α4β2) 2 α4 and(α4β2) 2 β2 nAChRs expressed. Br-PBTC (0.1~100 μM；0~140 seconds; HEK cells) reactivates long term desensitized nAChRs[1].