Systemic EMD 68843 injections reduce anxiety in the shock-probe, but not the plus-maze test

Selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors and 5-HT(1A) receptor agonists are believed to reduce anxiety. In the present study we examined the effects of injections of 5-(4-[4-(5-cyano-3-indolyl)-butyl]-1-piperazinyl)-benzofuran-2-carboxamide hydrochloride salt (EMD 68843), a 5-HT(1A) receptor agonist and selective 5-HT reuptake inhibitor, in two animal models of anxiety, plus-maze and shock-probe. Rats received intraperitoneal injections of vehicle, diazepam (2.5 mg/kg), or EMD 68843 (10, 20, or 40 mg/kg) 1 h prior to testing. Diazepam at the single dose tested and EMD 68843 dose-dependently (significantly at 20 and 40 mg/kg) reduced burying in shock-probe. However, only diazepam significantly increased open arm exploration in the plus-maze. Therefore, EMD 68843 has task specific anxiolytic properties.