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Effects of lysergic acid diethylamide (LSD) on temporal recovery (pre-pulse inhibition) of the acoustic startle response in the rat.

In a series of 6 experiments 40 mug/kg d-lysergic acid diethylamide (LSD) augmented acoustic startle amplitude in rats when long intertone intervals (4, 8, 16, or 32 sec) were used but not when short interstimulus intervals were used (0.02, 0.1, 0.5, 1, or 2 sec). In contrast, 8 mg/kg d-amphetamine augmented startle when either long or short interstimulus intervals were used. The results suggest that LSD augments startle by accelerating the decay of pre-pulse inhibition (temporal recovery process) which may be one mechanism by which LSD can alter sensory processing.

Acoustic Stimulation↗

Lysergic acid diethylamide- and mescaline-induced attenuation of the effect of punishment in the rat.

At a dose as low as 1 microgram per kilogram of body weight, lysergic acid diethylamide (LSD) significantly decreased the suppressive effect of electric shock on licking behavior of the rat. Attenuation of punishment was also obtained with mescaline, but neither dimethyltryptamine nor delta9-tetrahydrocannabinol was active in this test. Cyproheptadine and alpha-propyldopacetamide, drugs that interfere with the function of neurons that contain serotonin, have a behavioral effect similar to that of LSD and mescaline, which suggests that the attenuation of punishment produced by these hallucinogens may result from decreased activity of such neurons.

Amides↗

Determination of lysergic acid diethylamide in body fluids by high-performance liquid chromatography and fluorescence detection--a more sensitive method suitable for routine use.

A new method for determination of lysergic acid diethylamide (LSD) in body fluids by high-performance liquid chromatography and fluorescence detection was developed based on previously published methods. The new method is suitable for confirmation of samples tested positive by immunoassay, avoiding loss of LSD by absorption to surfaces. The reduced loss of LSD results in improved sensitivity. This is achieved by adding ethylene glycol to the samples, which cover glass surfaces. This principle can similarly be used to improve analysis of other drugs. Body fluids for analysis included urine and whole blood. An internal standard was applied for quantification of LSD. The new method offers satisfying precision data and has a detection limit of less than 0.05 ng/nL.

Body Fluids↗

Determination of lysergic acid diethylamide (LSD) in urine by instrumental high-performance thin-layer chromatography.

An instrumental high-performance thin-layer chromatographic (HPTLC) technique for the determination of lysergic acid diethylamide (LSD) in urine was developed. Before chromatographic separation, a single-step extraction with alkaline wash is performed. The procedure can detect less than 1 microgram LSD/L urine. Results of HPTLC determination are compared with those from a radioimmunoassay (RIA) procedure.

Chromatography, Thin Layer↗

(+)Lysergic acid diethylamide, but not its nonhallucinogenic congeners, is a potent serotonin 5HT1C receptor agonist.

Activation of central serotonin 5HT2 receptors is believed to be the primary mechanism whereby lysergic acid diethylamide (LSD) and other hallucinogens induce psychoactive effects. This hypothesis is based on extensive radioligand binding and electrophysiological and behavioral studies in laboratory animals. However, the pharmacological profiles of 5HT2 and 5HT1C receptors are similar, making it difficult to distinguish between effects due to activation of one or the other receptor. For this reason, it was of interest to investigate the interaction of LSD with 5HT1C receptors. Agonist-stimulated phosphoinositide hydrolysis in rat choroid plexus was used as a direct measure of 5HT1C receptor activation. (+)LSD potently stimulated phosphoinositide hydrolysis in intact choroid plexus and in cultures of choroid plexus epithelial cells, with EC50 values of 9 and 26 nM, respectively. The effect of (+)LSD in both systems was blocked by 5HT receptor antagonists with an order of activity consistent with interaction at 5HT1C receptors. Neither (+)-2-bromo-LSD nor lisuride, two nonhallucinogenic congeners of LSD, were able to stimulate 5HT1C receptors in cultured cells or intact choroid plexus. In contrast, lisuride, like (+)LSD, is a partial agonist at 5HT2 receptors in cerebral cortex slices and in NIH 3T3 cells transfected with 5HT2 receptor cDNA. The present finding that (+)LSD, but not its nonhallucinogenic congeners, is a 5HT1C receptor agonist suggests a possible role for these receptors in mediating the psychoactive effects of LSD.

Animals↗

Comparison of EMIT II, CEDIA, and DPC RIA assays for the detection of lysergic acid diethylamide in forensic urine samples.

In an effort to determine a practical, efficient, and economical alternative for the use of a radioimmunoassay (RIA) for the detection of lysergic acid diethylamide (LSD) in human urine, the performance of two photometric immunoassays (Dade Behring EMIT II and Microgenics CEDIA) and the Diagnostics Products Corp. (DPC) RIA were compared. Precision, accuracy, and linearity of the 3 assays were determined by testing 60 replicates (10 for RIA) at 5 different concentrations below and above the 500-pg/mL LSD cut-off. The CEDIA and RIA exhibited better accuracy and precision than the EMIT II immunoassay. In contrast, the EMIT II and CEDIA demonstrated superior linearity r2 = 0.9809 and 0.9540, respectively, as compared with the RIA (r2 = 0.9062). The specificity of the three assays was assessed using compounds that have structural and chemical properties similar to LSD, common over-the-counter products, prescription drugs and some of their metabolites, and other drugs of abuse. Of the 144 compounds studied, the EMIT II cross-reacted with twice as many compounds as did the CEDIA and RIA. Specificity was also assessed in 221 forensic human urine specimens that previously screened positive for LSD by the EMIT II assay. Of these, only 11 tested positive by CEDIA, and 3 were positive by RIA. This indicated a comparable specificity performance between CEDIA and RIA. This also was consistent with a previously reported high false-positive rate of EMIT II (low specificity). Each of the immunoassays correctly identified LSD in 23 out of 24 human urine specimens that had previously been found to contain LSD by gas chromatography-mass spectrometry at a cut-off concentration of 200 pg/mL. The CEDIA exhibited superior precision, accuracy, and decreased cross-reactivity to compounds other than LSD as compared with the EMIT II assay and does not necessitate the handling of radioactive materials.

Cross Reactions↗

Molecular genetic responses to lysergic acid diethylamide include transcriptional activation of MAP kinase phosphatase-1, C/EBP-beta and ILAD-1, a novel gene with homology to arrestins.

We recently demonstrated that the potent hallucinogenic drug lysergic acid diethylamide (LSD) dynamically influences the expression of a small collection of genes within the mammalian prefrontal cortex. Towards generating a greater understanding of the molecular genetic effects of hallucinogens and how they may relate to alterations in behavior, we have identified and characterized expression patterns of a new collection of three genes increased in expression by acute LSD administration. These genes were identified through additional screens of Affymetrix DNA microarrays and examined in experiments to assess dose-response, time course and the receptor mediating the expression changes. The first induced gene, C/EBP-beta, is a transcription factor. The second gene, MKP-1, suggests that LSD activates the MAP (mitogen activated protein) kinase pathway. The third gene, ILAD-1, demonstrates sequence similarity to the arrestins. The increase in expression of each gene was partially mediated through LSD interactions at 5-HT2A (serotonin) receptors. There is evidence of alternative splicing at the ILAD-1 locus. Furthermore, data suggests that various splice isoforms of ILAD-1 respond differently at the transcriptional level to LSD. The genes thus far found to be responsive to LSD are beginning to give a more complete picture of the complex intracellular events initiated by hallucinogens.

Animals↗

Responses of serotonergic and non-serotonergic neurons in the rat nucleus raphe magnus to systemic lysergic acid diethylamide.

Serotonergic and non-serotonergic neurons in the nucleus raphe magnus were identified by conduction velocities and spontaneous discharge rates. Eight of 13 serotonergic neurons were depressed by lysergic acid diethylamide (LSD) administration (40-50 micrograms/kg, i.p. or i.v.), while the others were non-responsive. Among 38 non-serotonergic neurons, 5 were depressed, 4 were excited and 29 were unaffected by systemic LSD at the same doses. It is thus concluded that LSD could act differently on serotonergic and non-serotonergic neurons in nucleus raphe magnus.

Action Potentials↗

On-line identification of lysergic acid diethylamide (LSD) in tablets using a combination of a sweeping technique and micellar electrokinetic chromatography/77 K fluorescence spectroscopy.

This work describes a novel method for the accurate determination of lysergic acid diethylamide (LSD) in tablets. A technique involving sweeping-micellar electrokinetic chromatography (MEKC) was used for the initial on-line concentration and separation, after which a cryogenic molecular fluorescence experiment was performed at 77 K. Using this approach, not only the separation of LSD from the tablet extract was achieved, but on-line spectra were readily distinguishable and could be unambiguously assigned. The results are in agreement with analyses by gas chromatography-mass spectrometry (GC-MS). Thus, this method, which was found to be accurate, sensitive and rapid, has the potential for use as a reliable complementary method to GC-MS in such analyses.

Chromatography, Micellar Electrokinetic Capillary↗

Automated extraction of lysergic acid diethylamide (LSD) and N-demethyl-LSD from blood, serum, plasma, and urine samples using the Zymark RapidTrace with LC/MS/MS confirmation.

A forensic procedure for the quantitative confirmation of lysergic acid diethylamide (LSD) and the qualitative confirmation of its metabolite, N-demethyl-LSD, in blood, serum, plasma, and urine samples is presented. The Zymark RapidTrace was used to perform fully automated solid-phase extractions of all specimen types. After extract evaporation, confirmations were performed using liquid chromatography (LC) followed by positive electrospray ionization (ESI+) mass spectrometry/mass spectrometry (MS/MS) without derivatization. Quantitation of LSD was accomplished using LSD-d3 as an internal standard. The limit of quantitation (LOQ) for LSD was 0.05 ng/mL. The limit of detection (LOD) for both LSD and N-demethyl-LSD was 0.025 ng/mL. The recovery of LSD was greater than 95% at levels of 0.1 ng/mL and 2.0 ng/mL. For LSD at 1.0 ng/mL, the within-run and between-run (different day) relative standard deviation (RSD) was 2.2% and 4.4%, respectively.

Body Fluids↗

Separation of D-lysergic acid diethylamide derivatives using micellar electrokinetic capillary chromatography.

By adjusting column temperature and applied electric field, a fast separation in micellar electrokinetic capillary chromatography was developed for the separation of D-lysergic acid diethylamide derivatives. A baseline separation of nine derivatives was accomplished with a run time of less than 12 min by utilizing elevated column temperature (60 degrees C) and an applied electric field of 387 V/cm. The number of plates generated per unit time for the separations completed at elevated temperatures was significantly higher when compared to separations at the same applied electric field but at lower temperatures (20 degrees C).

Chromatography, Micellar Electrokinetic Capillary↗

Antagonism of d-lysergic acid diethylamide and mescaline by 1-methyl-1, 2, 5, 6-tetrahydropyridine-N, N-diethyl-carboxamide (THPC).

Contractions of sheep umbilical vasculature induced by 5-hydroxytryptamine, mescaline and d-lysergic acid diethylamide (LSD) were antagonized by 1-methyl-1, 2, 5, 6-tetrahydropyridine-N, N-diethyl-carboxamide (THPC) 5 X 10(-4)M. THPC did not block contractile responses to angiotensin. The data are interpreted to support our previous suggestions that certain chemical entities representing portions of the LSD molecule may be effectively studied as antagonists to the hallucinogens. The present data indicate that THPC is a weak 5-hydroxytryptamine receptor antagonist.

Angiotensin II↗