Daily LSD administration selectively decreases serotonin2 receptor binding in rat brain

The effect of ten daily injections of saline or d-lysergic acid diethylamide (LSD) (260 micrograms/kg i.p.) on serotonin1 (5-hydroxytryptamine1, 5-HT1) and 5-HT2 receptor binding was determined in brain membranes from rats killed 24 h after the last injection. [3H]LSD (3.0 nM) was used with either 30.0 nM 5-HT or 70.0 nM cinanserin to estimate 5-HT1 and 5-HT2 receptors, respectively. LSD administration decreased 5-HT2 binding in cortex, striatum, hippocampus, and diencephalon/midbrain without altering 5-HT1 or total specific binding.