The rank order of potency for the physiological effects of three phenethylamine hallucinogens in the locus coeruleus (LC) was identical to that previously shown for their 5-HT2 binding affinity ((-) DOB > DOM > (+)DOB). The behaviorally inactive positional isomer of DOB, SL-7161, did not significantly affect LC unit activity. These results offer insight into structure-activity relationships at 5-HT2 receptors and support earlier findings that the actions of hallucinogens displayed in the LC are mediated via 5-HT2 receptors.
