Nor-LSD, or norLSD, also known as N,N-diethyl-6-norlysergamide or as N-desmethyllysergic acid diethylamide (N-desmethyl-LSD), is a serotonin receptor modulator and putative psychedelic of the lysergamide family related to lysergic acid diethylamide (LSD). It is the analogue of LSD in which the methyl group at the 6 position of the ergoline ring system has been removed.
According to Alexander Shulgin, nor-LSD showed no psychedelic effects at assessed doses of up to 500üg in humans, whereas LSD was active at doses as low as 50üg. Higher doses of nor-LSD do not appear to have been assessed.
Nor-LSD showed 5- to 29-fold lower affinity for the serotonin 5-HT<sub>2</sub> receptor compared to LSD (K<sub>i</sub> = 30âÂÂ158nM vs. 5.4nM, respectively). It also showed affinity for the serotonin 5-HT<sub>1</sub> receptor. In another more recent study however, nor-LSD showed similar or even higher affinities, activational potencies, and/or efficacies at the serotonin 5-HT<sub>1A</sub>, 5-HT<sub>2A</sub>, and 5-HT<sub>2B</sub> receptors as LSD, whereas it showed 36-fold lower affinity for the serotonin 5-HT<sub>2C</sub> receptor compared to LSD.
Nor-LSD failed to completely substitute for LSD in rodent drug discrimination tests even at very high doses. The greatest degree of substitution with nor-LSD was 75% at a dose of 7,420nM/kg, whereas 100% substitution occurred with LSD at a dose of 186nM/kg (a 40-fold lower dose). The was 2,594nM/kg for nor-LSD and 46nM/kg for LSD. Hence, nor-LSD was approximately 56-fold less potent than LSD in terms of producing LSD-like effects in rodents and failed to produce full LSD-like effects even at the highest assessed dose. In another study, nor-LSD failed to produce LSD-like electroencephalogram (EEG) changes in rabbits.
Nor-LSD has been reported to occur as a metabolite of LSD in rats and humans.
Derivatives of nor-LSD substituted at the 6 position include LSD (METH-LAD; 6-methyl), ETH-LAD (6-ethyl), PRO-LAD (6-propyl), BU-LAD (6-butyl), AL-LAD (6-allyl), and PARGY-LAD (6-propynyl), among others. There appears to be a length of about 3carbon atoms that can be tolerated at the 6 position before potent psychedelic activity is lost.
Nor-LSD was first described in the scientific literature, by Yuji Nakahara and Tetsukichi Niwaguchi, by at least 1971.