Psychedelia.dk

Post abstract og henvisning til ny spændene forskning. Lad være med at poste hele artikler mm de er frit tilgengelige og ikke omfattet af copyrigth.

Alle har muligheden for at få kopier af videnskablige artikler på Danmarks Natur- og Læge videnskablige bibliotek http://www.kb.dk/da/kub/campusbib/kubnord/index.html

Vigtigste læsning for folk med interesse i hallucingene stoffer. Den mest omfattende gennemgang af teorien til dato.

Forfatter: Nichols, DE
Tidsskrift: Pharmacology & Therapeutics
År: 2004
Nummer: 101(2)
Side: 131-81

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.

PUBMED LINK

Ny forskning viser afkøling og ophedning af kroppen efter behandling med MDMA er afhængig af omgivelsernes temperatur.

Forfattere: Banks ML, Sprague JE, Kisor DF, Czoty PW, Nichols DE, Nader MA.
Tidsskrift: Drug Metabolites and Dispositions
År: 2007
Nummer: 35(10):
Side: 1840-5

Ambient temperature effects on 3,4-methylenedioxymethamphetamine-induced thermodysregulation and pharmacokinetics in male monkeys.

Changes in ambient temperature are known to alter both the hyperthermic and the serotonergic consequences of 3,4-methylenedioxymethamphetamine (MDMA). Metabolism of MDMA has been suggested to be a requisite for these neurotoxic effects, whereas the hyperthermic response is an important contributing variable. The aim of the present study was to investigate the interaction between ambient temperature, MDMA-induced thermodysregulation, and its metabolic disposition in monkeys. MDMA (1.5 mg/kg i.v.) was administered noncontingently at cool (18 degrees C; n = 5), room (24 degrees C; n = 7), and warm (31 degrees C; n = 7) ambient temperatures. For 240 min following MDMA administration, core temperature was recorded and blood samples were collected for analysis of MDMA and its metabolites 3,4-dihydroxymethamphetamine (HHMA), 3,4-dihydroxyamphetamine, and 3,4-methylenedioxyamphetamine (MDA). A dose of 1.5 mg/kg MDMA induced a hypothermic response at 18 degrees C, a hyperthermic response at 31 degrees C, and did not significantly change core temperature at 24 degrees C. Regardless of ambient temperature, plasma MDMA concentrations reached maximum within 5 min, and HHMA was a major metabolite. Curiously, the approximate elimination half-life (t(1/2)) of MDMA at 18 degrees C (136 min) and 31 degrees C (144 min) was increased compared with 24 degrees C (90 min) and is most likely because of volume of distribution changes induced by core temperature alterations. At 18 degrees C, there was a significantly higher MDA area under the concentration-time curve (AUC) and a trend for a lower HHMA AUC compared with 24 degrees C and 31 degrees C, suggesting that MDMA disposition was altered. Overall, induction of hypothermia in a cool environment by MDMA may alter its disposition. These results could have implications for MDMA-induced serotonergic consequences.

PUBMED LINK

Aber der har lært at diskriminere 5HT2A virkende hallucinogener (LSD, DOM, Psilocybin) fra andre stoffer (Amfetamin, Ketamin, Opiater), giver ikke respons kappa opioid receptor agonists U-50488 and Salvinorin A (Salvie Divinorum), hvilket betyder at forskellige hallucinogener giver forskellige stimulerede respons i mammals. Og bekræfter den absolutte forskel i virkningen af Salvie Divinorum og LSD.

Forfattere: Li JX, Rice KC, France CP.
Tidsskrift: Journal of Pharmacological Experimental Techniques
År: 2007
Nummer: Ahead of print
Side: -

Discriminative stimulus effects of 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) in rhesus monkeys.

Discriminative stimulus effects of 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) and related drugs have been studied extensively in rodents, although the generality of those findings across species is not known. The goals of this study were to see whether monkeys could discriminate DOM and to characterize the DOM discriminative stimulus by studying a variety of drugs, including those with hallucinogenic activity in humans. Four rhesus monkeys discriminated between 0.32 mg/kg (s.c.) of DOM and vehicle after an average of 116 (range=85-166) sessions while responding under a fixed ratio (FR) 5 schedule of stimulus shock termination. Increasing doses of DOM occasioned increased responding on the drug lever with the training dose occasioning DOM-lever responding for up to 2 hrs. The serotonin (5-HT)2A/2C receptor antagonists ritanserin and ketanserin, the 5-HT2A receptor antagonist MDL100907 and its stereoisomer MDL100009, but not haloperidol, completely blocked the discriminative stimulus effects of DOM. Quipazine as well as several drugs with hallucinogenic activity in humans, including (+)lysergic acid diethylamide (LSD), (-)DOM and 2,5-dimethoxy-4-(n)-propylthiophenethylamine (2C-T-7), occasioned DOM-lever responding. The kappa opioid receptor agonists U-50488 and salvinorin A (a hallucinogen) did not exert DOM-like effects and neither did ketamine, phencyclidine, amphetamine, methamphetamine, cocaine, morphine, yohimbine, fenfluramine, 8-OH-DPAT or N-0434. These data confirm in non-human primates a prominent role for 5-HT2A receptors in the discriminative stimulus effects of some drugs with hallucinogenic activity in humans. The failure of another drug with hallucinogenic activity (salvinorin A) to substitute for DOM indicates that different classes of hallucinogens exert qualitatively different discriminative stimulus effects in non-humans.

PUBMED LINK

Artikkel gennemgår nuværende viden i forhold til stof brug (primært Cannabis) og schitzophreni.

Forfattere: Coulston CM, Perdices M, Tennant CC.
Tidsskrift: Australian and New Zealand Journal of Psychiatry.
År: Nov 2007
Nummer: 41
Side: 869-84

The Neuropsychology of cannabis and other substance use in schizophrenia: review of the literature and critical evaluation of methodological issues.

Research on the neuropsychology of substance use in schizophrenia has been steadily growing over the past decade. However, significant gaps remain in the knowledge of individual substances and their relationship to cognition in the schizophrenia spectrum disorders. Approximately 65 studies to date have directly examined this relationship. Of these, approximately 20 have focused on nicotine, 15 on alcohol, 10 on cocaine, three on stimulants/hallucinogens, one on benzodiazepines, 10 on polydrug abuse, and seven on cannabis. Research on cannabis is especially lacking, given that worldwide it is the most commonly used illicit drug in schizophrenia, is used at higher rates in schizophrenia than in the general population, and makes its own unique contribution to the onset and prognosis of schizophrenia. In the present paper an overview of the neuropsychology literature on substance use in schizophrenia is presented, with special emphasis on cannabis. This incorporates a discussion of the methodological limitations inherent in these studies, and range of potential confounding variables that were not considered or controlled, providing directions for future research into the cognitive correlates of cannabis and other substance use in schizophrenia.

PUBMED LINK