SL651498 was identified as a drug development candidate from a research program designed to discover subtype-selective GABA(A) receptor agonists for the treatment of generalized anxiety disorder and muscle spasms. SL651498 displayed high affinity for GABA(A) receptors containing alpha(1) and alpha(2 subunits, and weaker affinity for alpha5-containing GABA(A) receptors, it behaved as a full agonist at recombinant t GABA(A) receptors containing alpha(2) and alpha(3) subunits, and as a partial agonist at recombinant GABA(A) receptors expressing alpha(1) and alpha(5) subunits. It was shown, that SL651498 represented a promising alternative to agents currently used for the treatment of anxiety disorders and muscle spasms without the major side effects seen with classical benzodiazepines).

6-alpha-Naloxol is active metabolite of naloxone. 6-alpha-Naloxol was shown to be neutral antagonist at the mu receptor in vitro, with no affect on cAMP levels or GTPitalic gammaS binding, regardless of morphine pretreatment. It elicits withdrawal behaviour and conditioned place aversion in morphine pretreated rodents.