“…Receptors containing the a1 subunit exhibit BZ 1 receptor pharmacology, with a high affinity for classical BZ agonists, such as diazepam and alprazolam, and also for the atypical BZ agonists, CL218872 and zolpidem. Transfection studies of recombinant GABA A receptors comprised of a1, b, g1, or g2 subunits exhibit BZ 1 receptor pharmacology, with highaffinity binding for zolpidem (Barnard et al, 1988;Mehta and Ticku, 1999), which binds BZ 1 receptors with an affinity (k d B7 nM) that is at least 20 times greater than for BZ 2 receptors (Arbilla et al, 1986). Receptors composed of the a2, a3, or a5 subunits show BZ 2 receptor profiles, with high affinity for classical BZ agonists, but greatly reduced affinity for zolpidem.…”