( 3 H)lysergic acid diethylamide: cellular autoradiographic localization in rat brain

Lysergic acid diethylamide causes mouse retinal damage by up-regulating p-JAK1/p-STAT1

Purpose: Lysergic acid diethylamide (LSD) is a powerful hallucinogen with high potential for abuse. There is far less known about its effects on the retina, especially the underlying mechanisms. This study was to investigate the acute toxicity of LSD on the retina of C57 mice and its mechanisms of action.Methods: C57 mice were treated with LSD at progressively increasing doses (0.2-1.2 mg/kg) intraperitoneally two times daily for 5 days, mice treated with saline served as negative control. Electroretinography (ERG) was used to test the function of the retina. Toluidine blue staining was used to detect the morphology of the retina. Enzyme-linked immunosorbent assay (ELISA) was used to measure the apoptosis-related factors. Real-time PCR and western blot techniques were used to measure expression changes of genes and proteins, respectively.Results: LSD treatment caused retinal damage, as shown by a decrease in ERG response and the loss of photoreceptor cells. LSD treatment also increased apoptosis through up-regulating the expression of p-JAK1/p-STAT1.Conclusions: Our study indicated that intraperitoneal administration of LSD-induced retinal damage of C57 mice, at least partially through regulating the JAK/STAT pathway.

The pharmacology of lysergic acid diethylamide: a review

Lysergic acid diethylamide (LSD) was synthesized in 1938 and its psychoactive effects discovered in 1943. It was used during the 1950s and 1960s as an experimental drug in psychiatric research for producing so-called "experimental psychosis" by altering neurotransmitter system and in psychotherapeutic procedures ("psycholytic" and "psychedelic" therapy). From the mid 1960s, it became an illegal drug of abuse with widespread use that continues today. With the entry of new methods of research and better study oversight, scientific interest in LSD has resumed for brain research and experimental treatments. Due to the lack of any comprehensive review since the 1950s and the widely dispersed experimental literature, the present review focuses on all aspects of the pharmacology and psychopharmacology of LSD. A thorough search of the experimental literature regarding the pharmacology of LSD was performed and the extracted results are given in this review. (Psycho-) pharmacological research on LSD was extensive and produced nearly 10,000 scientific papers. The pharmacology of LSD is complex and its mechanisms of action are still not completely understood. LSD is physiologically well tolerated and psychological reactions can be controlled in a medically supervised setting, but complications may easily result from uncontrolled use by layman. Actually there is new interest in LSD as an experimental tool for elucidating neural mechanisms of (states of) consciousness and there are recently discovered treatment options with LSD in cluster headache and with the terminally ill.

Hallucinogens

Hallucinogens (psychedelics) are psychoactive substances that powerfully alter perception, mood, and a host of cognitive processes. They are considered physiologically safe and do not produce dependence or addiction. Their origin predates written history, and they were employed by early cultures in a variety of sociocultural and ritual contexts. In the 1950s, after the virtually contemporaneous discovery of both serotonin (5-HT) and lysergic acid diethylamide (LSD-25), early brain research focused intensely on the possibility that LSD or other hallucinogens had a serotonergic basis of action and reinforced the idea that 5-HT was an important neurotransmitter in brain. These ideas were eventually proven, and today it is believed that hallucinogens stimulate 5-HT(2A) receptors, especially those expressed on neocortical pyramidal cells. Activation of 5-HT(2A) receptors also leads to increased cortical glutamate levels presumably by a presynaptic receptor-mediated release from thalamic afferents. These findings have led to comparisons of the effects of classical hallucinogens with certain aspects of acute psychosis and to a focus on thalamocortical interactions as key to understanding both the action of these substances and the neuroanatomical sites involved in altered states of consciousness (ASC). In vivo brain imaging in humans using [(18)F]fluorodeoxyglucose has shown that hallucinogens increase prefrontal cortical metabolism, and correlations have been developed between activity in specific brain areas and psychological elements of the ASC produced by hallucinogens. The 5-HT(2A) receptor clearly plays an essential role in cognitive processing, including working memory, and ligands for this receptor may be extremely useful tools for future cognitive neuroscience research. In addition, it appears entirely possible that utility may still emerge for the use of hallucinogens in treating alcoholism, substance abuse, and certain psychiatric disorders.

Lead exposure and child behavior

OBJECTIVES

Unlike cognitive impairments associated with lead exposure, lead-associated child behavior problems have been difficult to specify, particularly in young children.

METHODS

The Child Behavior Checklist (CBCL) and the Center for Epidemiologic Studies Depression Scale were used as the outcome and confounding variables, respectively, of major interest. These measures were examined with respect to blood lead levels of 201 African-American children aged 2 through 5 years.

RESULTS

In comparison with the low exposed group, the high exposed group (two consecutive blood lead levels greater than or equal to 15 micrograms/dL) had a significantly higher mean CBCL Total Behavior Problem Score (TBPS) and Internalizing and Externalizing scores; when other factors, including maternal depressive symptomatology, were controlled for, regression procedures indicated a .18-point TBPS increase for each unit increase in lead and a 5.1-point higher TBPS in the high exposed group; children in this group were 2.7 times more likely to have a TBPS in the clinical range.

CONCLUSIONS

Through its use of a standardized parent-report measure of behavior and its consideration of maternal morale in multiple linear and logistic regression procedures, this study provides further evidence of lead's detrimental effect on child behavior at levels typical of present-day exposure.

Serotonin2 agonist administration down-regulates rat brain serotonin2 receptors

Daily administration of D-lysergic acid diethylamide (LSD) was previously shown to decrease serotonin2 (5-HT2) receptor binding in rat brain. Recently, 4-substituted derivatives of 1-(2,5-dimethoxyphenyl)-2-aminopropane, the substitution being with either iodine (DOI) or bromine (DOB), have been suggested to be relatively selective 5-HT2 agonists. These compounds share common behavioral and neurophysiological effects with LSD, suggested to be 5-HT2 receptor mediated, and the purpose of the present study was to determine whether they also affect 5-HT2 receptor binding after systemic administration in a similar way to LSD. Administration of DOI (1.0 mg/kg) or DOB (0.5 mg/kg) for 7 days resulted in a decrease in 5-HT2 binding, as evaluated with [3H]ketanserin, similar to the decrease after LSD. In a further evaluation of the parallelism of LSD and 5-HT2 agonists, it was found that 24 hr after one administration of a low dose of LSD (130 ug/kg) or DOI (1.0 mg/kg), there was no change in binding, but there was a decrease 24 hr after a high dose (LSD, 650 micrograms/kg; DOI, 7.0 mg/kg). Four hours after the high dose of LSD or DOI there was also a decrease in 5-HT2 binding. Thus, results have shown that 5-HT2 agonists are capable of down-regulating 5-HT2 receptors and that LSD acts in a parallel fashion. This study has also demonstrated that 5-HT2 receptors can be modified within hours after drug administration.

Hallucinogenic drug research--if so, so what? Symposium summary and commentary

The conference brought a critical focus both on older findings and new strategies in hallucinogenic drug research as well as on behavioral and electrophysiologic tools that correlate with neurobehavioral and neurochemical events. A number of unsolved problems to be investigated were noted. The sensitizing effects of both mescaline and LSD on other inputs at motor nuclei or at limbic sites, and effects on afferent processes were examples of important new directions as were drug discrimination tests that can determine the relative roles of aminergic systems in drug effect. Fixed ratio operant schedules can differentiate serotonin blocking agents, detect active indole psychotomimetics and demonstrate temporal and tolerance parameters relevant to drug induced neurochemical changes. Data and critique as well as pharmacokinetics no longer support the presynaptic-disinhibition model of LSD effects, nor is LSD induced "slowed turnover" of serotonin seen as an accurate description of neurochemical changes. The distinct nerve ending biochemical changes after LSD are reviewed. Subcellular compartmental analyses require a radical revision of the picture of the ratio in the nerve ending of cytoplasmic and vesicular amine as well as factors normally regulating accessibility of amine to intraneuronal MAO.

Morphologic alterations in the Purkinje neuron of the rat induced by lysergic acid diethylamide and fixation

The effect of lysergic acid diethylamide (LSD) on the morphology of the cerebellar cortex of the rat was studied with electron microscopy. Hippocampal electrical activity was used as an objective measure of drug efficacy. At a dose of 1700 micrograms/kg, the amplitude from the hippocampus was diminished (in 2 to 5 min) and this effect lasted for about 65 to 165 min. A morphologic alteration consisting of cisternal stacks occurred in the dendrites of Purkinje neurons of rats treated with this dose of LSD, with the perfusion carried out correctly. These stacks of smooth endoplasmic reticulum were seen 2 h after injection and persisted for at least 8 h. A reduction in the volume of perfused fluid to less than 500 ml caused similar changes in the dendrites of the Purkinje neuron of untreated rats; this was one way to experimentally induce a faulty perfusion. With LSD and faulty perfusion (reduced volume) more severe changes occurred in the dendrites and small stacks of smooth endoplasmic reticulum were seen in the Purkinje soma; similar changes were also seen when the perfusion of a control animal was mismanaged during the initial 3 min. The Purkinje neuron seems to manifest morphologic alterations, generally of two types, with exposure to a variety of noxious agents. The LSD caused some perturbation of this neuron, and this was found under properly controlled conditions of fixation. The results are interpreted as indicating that LSD is causing a metabolic alteration which could disrupt the synaptic activity over several hours.

Nerve terminal effects of indoleamine psychotomimetics on 5-hydroxytryptamine

The mode of action of indoleamine psychotomimetics has been closely linked to 5-HT. Early work showed increases in rat brain levels of 5-HT which were later localized to the nerve-ending fraction. With improved methodology, the 5-HT increment was further detected in the synaptic vesicle fraction. These effects were obtained with several indoleamine hallucinogens but not with mescaline. LSD has been most thoroughly studied and has served as the prototypical compound in ascertaining the mode of action of these drugs. Pretreatment with reserpine abolished the 5-HT effects of LSD in the vesicular fraction. However, a new compartment, termed "juxtavesicular," displayed 5-HT increases following reserpine and LSD. A soluble binding site for 5-HT within the synaptoplasm has been postulated in confirmation of independent results by other groups of investigators. The origin of the 5-HT increment appears to be associated with newly synthesized amine. This was deduced from experiments involving various 5-HT synthesis blockers. To ascertain whether inhibition of raphé neuronal firing is responsible for the accumulation of 5-HT at the nerve terminal, two sets of experiments were performed. Destruction of the raphé cell bodies by radiofrequency lesions failed to abolish the LSD-induced 5-HT increase early after the lesion. Destruction of cortical 5-HT neurons with the neurotoxin 5,7-dihydroxytryptamine completely abolished the 5-HT effect of LSD. It was concluded that an intact nerve terminal is necessary for the expression of the LSD-mediated increases in 5-HT. A LSD "autoreceptor" is postulated, possibly identical to a 5-HT presynaptic receptor inhibiting the release of 5-HT.

Chronic intraventricular administration of lysergic acid diethylamide (LSD) affects the sensitivity of cortical cells to monocular deprivation

In kittens, but not in adult cats, depriving one eye of pattern vision by suturing the lids shut (monocular deprivation or MD) for one week reduces the proportion of binocular units in the visual cortex. A sensitivity of cortical units in adult cats to MD can be produced by infusing exogenous monoamines into the visual cortex. Since LSD interacts with monoamines, we have examined the effects of chronic administration of LSD on the sensitivity to MD for cortical cells in adult cats. Cats were assigned randomly to one of four conditions: MD/LSD, MD/No-LSD, No-MD/LSD, No-MD/No-LSD. An osmotic minipump delivered either LSD or the vehicle solution alone during a one-week period of MD. The animals showed no obvious anomalies during the administration of the drug. After one week the response properties of single units in area 17 of the visual cortex were studied without knowledge of the contents of the individual minipumps. With the exception of ocular dominance, the response properties of units recorded in all animals did not differ from normal. In the control animals (MD/No-LSD, No-MD/LSD, No-MD/No-LSD) the average proportion of binocular cells was 78%; similar to that observed for normal adult cats. However, in the experimental animals, which received LSD during the period of MD, only 52% of the cells were binocular. Our results suggest that chronic intraventricular administration of LSD affects either directly or indirectly the sensitivity of cortical neurons to MD.

Characterization and radioautography of [3H]LSD binding by rat brain slices in vitro: the effect of 5-hydroxytryptamine

Binding of D-[3H]lysergic acid diethylamide (LSD) to rat coronal brain slices and its blockade by 5-hydroxytryptamine (5-HT) had characteristics similar to those of brain homogenates in respect of KD, kinetics and reversibility of binding. Radioautography was done on slices that had been incubated in 6 nM [3H] LSD and on adjacent slices incubated in the same concentration of tritiated LSD plus 10(-5) M of 5-HT. Choroid plexus showed densest labeling of [3H] LSD. In neuropil, dense labeling occurred within parts of the hippocampal formation except for fields CA2 and CA3 which were sparsely labeled. All layers of the cortex except the posterior cingulate gyrus were labeled by LSD. 5-HT blocked labeling of choroid plexus, hippocampal formation, septum, pons, medulla and parts of cortex but only reduced labeling of most other structures. LSD binding sites may relate to some of its pharmacological effects.

The pineal and psychiatry: a review

The pineal body in man is an active endocrine gland throughout life. Historically the gland has been associated with speculation on the nature of mind and its disorders. Modern research is now demonstrating it to be an endocrine gland capable of affecting the brain and behaviour. The implications for future research into this aspect of pineal function are discussed in the context of a critical review of the current literature.

The uptake of delta9-tetrahydrocannabinol in choroid plexus and brain cortex in vitro and in vivo

[3H]delta9 Tetrahydrocannabinol (delta9-THC) was actively transported by the choroid plexus and cerebral cortical slices of the rabbit when incubated as a BSA-microsuspension in artificial rabbit CSF. The transport system for delta9-THC in choroid plexus had a V max of 174 nmoles/mg tissue/h, approximately 9-fold greater than that observed for cortical slices. In vivo experiments demonstrated a preferential distribution of delta9-THC in choroid plexus at 1 h after intravenous injection. These results indicate that delta9-THC is actively accumulated by choroidal epithelium and may also be transported across the epithelial stroma into the capillary circulation. This suggests that the choroid plexus participates in the regulation of delta9-THC concentration in CSF and indirectly in brain by means of the "sink" function of the CSF.

Lysergic acid diethylamide: effect on histone acetylation in rabbit brain

Lysergic acid diethylamide increased acetylation of histones in rabbit cerebral hemispheres and midbrain 30 minutes after intravenous administration of the drug at doses of 10 and 100 micrograms per kilogram of body weight. Evidence for the stimulation of acetylation in individual histone bands was obtained after separation by electrophoresis on polyacrylamied gels.