Experimental CNS ischemia: serotonin antagonists reduce or prevent damage.

We tested three serotonin antagonists--lysergic acid diethylamide (LSD), 2-bromolysergic acid diethylamide (BOL), and cinanserin--for effects on experimental spinal cord ischemia in the rabbit. Blood flow to spinal cord was obstructed. Drugs were administered before or after initiation of occlusion, and flow was later restored. When LSD was given 5 minutes after the onset of occlusion, the duration of ischemia required to produce neurologic abnormality was prolonged, but this protection was temporary. BOL and cinanserin treatment 5 minutes after the onset of ischemia was beneficial because neurologic improvement was permanent, and pretreatment with these drugs also markedly reduced damage. Therefore, several serotonin antagonists can prevent or reduce spinal cord damage when administered before or after the onset of ischemia.