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At least 613 records · Page 34Linked to original sources
PubMed1992

Pharmacological characterization of RP 62203, a novel 5-hydroxytryptamine 5-HT2 receptor antagonist.

1. RP 62203 (2-[3-(4-(4-fluorophenyl)-piperazinyl)propyl]naphto[1,8- ca]isothiazole-1,1-dioxide) is a novel naphtosultam derivative which shows very high affinity for 5-HT2 receptors in the rat cerebral cortex (Ki = 50.0 pM). 2. RP 62203 is relatively selective for this sub-type of 5-hydroxytryptamine (5-HT) receptor, having lower affinity for the 5-HT1A receptor and very low affinity for the 5-HT, receptor. RP 62203 displayed low to moderate affinity for alpha 1-adrenoceptors, dopamine D2 receptors and histamine H1 receptors. 3. In vivo binding experiments demonstrated that oral administration of low doses of RP 62203 led to a long-lasting (greater than 6 h) occupation of cortical 5-HT2 receptors (ID50 = 0.39 mgkg-1). 4. In cortical slices from the neonatal rat, RP 62203 potently inhibited inositol phosphate formation evoked by 5-HT, with an IC50 of 7.76 nM. 5. The activity of neurones in the raphé and their responses to microiontophoretically applied 5-HT were studied with extracellular recording electrodes in the anaesthetized rat. RP 62203 potently and dose-dependently blocked excitations evoked by 5-HT when administered at doses of 0.5-4.0 mg kg-1, i.p. In contrast, neither 5-HT-evoked depressions nor glutamate-evoked excitations of raphé neuronal firing were blocked by RP 62203 at doses as high as 8.0 mg kg-1, i.p. 6. Head twitches induced by 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) could be abolished by low doses of RP 62203 in mice (ED50 = 0.44 mg kg-1, p.o.) and in rats (ED50 = 1.54 p.o.). Similar results were obtained with mescaline and 5-hydroxytryptophan (5-HTP). 7. The potency of RP 62203 was compared with that of three other 5-HT2 receptor antagonists, ritanserin, ICI 169,369 and ICI 170,809. In all models, RP 62203 showed similar activity to ritanserin, whilst either ICI 169,369 or ICI 170,809 was several fold less active. 8. It is concluded that RP 62203 is a potent and selective antagonist at 5-HT2 receptors in the rodent central nervous system.

Action Potentials↗
PubMed1990

Monoamines and schizophrenia.

The hypothesis that central biogenic amines may play a role in the pathophysiology of schizophrenia was originally based upon the fact that hallucinogenic and antipsychotic drugs have profound effects on central transmitter pathways where dopamine, noradrenaline and serotonin are involved. The structural similarities between hallucinogenic drugs such as amphetamine and mescaline, and catecholamines on the one hand and lysergic acid diethylamide (LSD) and indolamines such as serotonin on the other hand have by direct experimentation been shown to explain their important effects on the transmitter systems. The marked effect of several classes of chemically different antipsychotic drugs on central dopamine receptor function formed the basis for the dopamine hypothesis regarding the mechanisms of action of these drugs and also for the hypothesis that dopamine D2 receptor function played a significant role in the pathophysiology of schizophrenia. Direct experimental analysis of aminergic functions in the brain of schizophrenic patients, both during life and post mortem, has been and will for the foreseeable future continue to be a rational approach to the further elucidation of the validity of these hypotheses. Analysis of metabolite levels in the cerebrospinal fluid and plasma of schizophrenic patients has shown great variation in the results with reports of both elevated and reduced release of amines in the brains of schizophrenic patients. Analysis of the aminergic receptor structures in the postmortem human brain has relatively consistently revealed an increased density of D2 receptors in the major basal ganglia of schizophrenic patients. Whether these alterations represent a primary feature of brain structure in schizophrenia or a drug-induced effect still remains to be shown. Positron emission tomographic (PET) scan studies of D2 receptors in schizophrenia have demonstrated both increased densities and absence of change in the characteristics of D2 receptors in the patients as compared to matched controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Antipsychotic Agents↗
PubMed1996

Ecstasy induced pneumomediastinum.

Two cases are reported of pneumomediastinum induced by the use of Ecstasy, a semi-synthetic hallucinogenic compound related to amphetamine and mescaline which has become established as a recreational drug in the UK since the late 1980s. Both cases recovered without incident, but it is important that the possible complications of this drug be publicised so that at risk subjects can be diagnosed early and managed appropriately.

3,4-Methylenedioxyamphetamine↗
PubMed2002

What geometric visual hallucinations tell us about the visual cortex.

Many observers see geometric visual hallucinations after taking hallucinogens such as LSD, cannabis, mescaline or psilocybin; on viewing bright flickering lights; on waking up or falling asleep; in "near-death" experiences; and in many other syndromes. Klüver organized the images into four groups called form constants: (I) tunnels and funnels, (II) spirals, (III) lattices, including honeycombs and triangles, and (IV) cobwebs. In most cases, the images are seen in both eyes and move with them. We interpret this to mean that they are generated in the brain. Here, we summarize a theory of their origin in visual cortex (area V1), based on the assumption that the form of the retino-cortical map and the architecture of V1 determine their geometry. (A much longer and more detailed mathematical version has been published in Philosophical Transactions of the Royal Society B, 356 [2001].) We model V1 as the continuum limit of a lattice of interconnected hypercolumns, each comprising a number of interconnected iso-orientation columns. Based on anatomical evidence, we assume that the lateral connectivity between hypercolumns exhibits symmetries, rendering it invariant under the action of the Euclidean group E(2), composed of reflections and translations in the plane, and a (novel) shift-twist action. Using this symmetry, we show that the various patterns of activity that spontaneously emerge when V1's spatially uniform resting state becomes unstable correspond to the form constants when transformed to the visual field using the retino-cortical map. The results are sensitive to the detailed specification of the lateral connectivity and suggest that the cortical mechanisms that generate geometric visual hallucinations are closely related to those used to process edges, contours, surfaces, and textures.

Hallucinations↗
PubMed1977

Clinical pharmacology of phencyclidine toxicity.

Phencyclidine appears to be unique in action compared with other psychedelic drugs, and its effects are less dependent upon the individual's personality than are the effects of LSD or mescaline. The authors discuss the sensory, psychological, and behavioral symptoms of phencyclidine intoxication. Most cases are of short duration and the only treatment necessary may be observation together with minimal stimulation and diazepam. However, prolonged and severe behavioral disturbances, exaggeration of preexisting thought disorder, and serious medical complications commonly occur and must be considered in the treatment plan.

Cognition↗
PubMed1976

Extraordinary experiences during cross-modal perception.

9 Ss were requested to perceive simultaneously the taste of beer and a rhythmic sound, the pitch of which could be varied. The frequencies at which Ss experienced harmony between the taste and the sound were determined. At the pitch of harmony Ss reported characteristic experiences, e.g., optimum taste of the beer, rhythmic sensations in the head, and tickling sensations in the jaws and the mouth. 3 Ss also reported experiences resembling those described by persons under the influence of such drugs as mescaline, psilocybin, LSD, and cannabis.

Acoustic Stimulation↗
PubMed1980

Specific drug use and violence in delinquent boys.

Delinquent boys who had been committed to a training school were interviewed by a psychiatrist to determine drug abuse status. Crimes that were officially recorded were classified as person offenses or property offenses, and the number of offenses was determined from the juvenile record. Drug scores were given subjects for each of 13 drug categories according to the following scale: 0, no use of drug; 1 to 4 v, varying use frequencies increasing in stepwise fashion but not reaching abuse proportions; 5, use greater than 8 days per month and abuse as defined in DSM III. Subject's number of crimes against persons were correlated with subject's drug scores for each of 13 drug categories. Five drugs had significantly positive correlations: phencyclidine, barbiturates, cocaine, Valium, and amphetamines. Scores for alcohol, LSD, mescaline, volatile substances, codeine, marijuana, heroin, and morphine did not correlate significantly with the number of person offenses in the person offender group. Mean drug scores for 13 drug categories of all subjects who were violent person offenders were compared with drug scores of subjects who were property only offenders. The t tests for independent means revealed that drug scores were significantly higher in the person offending group for five drugs: marijuana, alcohol, cocaine, heroin, and LSD. A high drug score for marijuana was the most predictive of all drug scores for membership in the person offending group.

Adolescent↗
PubMed2000

Nonmedical drug use among adolescent students: highlights from the 1999 Ontario Student Drug Use Survey.

BACKGROUND: During the 1990s, rates of nonmedical drug use among adolescents escalated. We assessed data from 5 cycles of the Ontario Student Drug Use Survey for overall trends in the proportion of students reporting illegal drug use between 1991 and 1999. METHODS: The survey is a repeated, cross-sectional, 2-stage cluster-design survey of students enrolled in grades 7, 9, 11 and 13. Outcome measures were prevalence of use of 17 drugs, including alcohol and tobacco, over the 12 months preceding the survey. RESULTS: The rates of drug use increased between 1993 and 1999. The 95% confidence intervals (CIs) for the differences in proportions between 1997 and 1999 indicated significant increases in the overall use of 6 drugs: alcohol (95% CIdiff 6.1, 1.9-10.3), cannabis (95% CIdiff 46.3, 0.2-8.4), glue (95% CIdiff 2.3, 1.3-3.3), other solvents (95% CIdiff 5.0, 3.1-6.3), barbiturates (95% CIdiff 1.9, 0.4-3.4) and hallucinogens such as mescaline and psilocybin (95% CIdiff 3.5, 0.8-6.9). Fewer grade 7 students in 1999 than in earlier cohorts reported using alcohol or cigarettes by age 9. INTERPRETATION: The public health implications of the findings are mixed. On the positive side, there is no evidence of increases in early onset of drug use. On the negative side, the overall proportion of students reporting illegal drug use has continued to rise.

Adolescent↗
PubMed2001

The pharmacology and toxicology of "ecstasy" (MDMA) and related drugs.

"Ecstasy" (MDMA) and related drugs are amphetamine derivatives that also have some of the pharmacological properties of mescaline. They have become popular with participants in "raves," because they enhance energy, endurance, sociability and sexual arousal. This vogue among teenagers and young adults, together with the widespread belief that "ecstasy" is a safe drug, has led to a thriving illicit traffic in it. But these drugs also have serious toxic effects, both acute and chronic, that resemble those previously seen with other amphetamines and are caused by an excess of the same sympathomimetic actions for which the drugs are valued by the users. Neurotoxicity to the serotonergic system in the brain can also cause permanent physical and psychiatric problems. A detailed review of the literature has revealed over 87 "ecstasy"-related fatalities, caused by hyperpyrexia, rhabdomyolysis, intravascular coagulopathy, hepatic necrosis, cardiac arrhythmias, cerebrovascular accidents, and drug-related accidents or suicide. The toxic or even fatal dose range overlaps the range of recreational dosage. The available evidence does not yet permit an accurate assessment of the size of the problem presented by the use of these drugs.

Amphetamines↗
PubMed1975

Adaptive changes in behavior after repeated administration of various psychoactive drugs.

Evidence has been presented that d-amphetamine interacts with various types of behavior in the context of a conditioning paradigm. Rats exposed simultaneously to a locomotor activity measurement and three dose levels of d-amphetamine on repeated occasions gradually developed dose-related enhancement of drug-stimulated activity, which persisted after discontinuation of the drug. Rats trained in FR-operant chambers with food reinforcement showed a decrease in the rate of lever pressing after administration of d-amphetamine. Tolerance to this effect required varying numbers of daily drug injections, according to the subject's degree of prior drug experience. In both situations the drug administrations were coupled with the behavioral measure to allow for conditioning effects. In a continuous avoidance procedure the initial dose of d-amphetamine did not enhance response rate, although subsequent doses did produce significant stimulation. Even when the initial doses were administered out of temporal phase with the avoidance measurement, the simultaneous administration of the drug and the behavioral procedure on a subsequent day resulted in a significant drug-induced stimulation of response rate. Thus, in this particular instance, the conditioning influence of the earlier doses was apparent whether or not the drug effect occurred in contiguity with the avoidance measurement. Other reports in the literature (16) suggest that hallucinogenic drug action may be characterized by the peculiar "pause" in an FR pattern of responding for food reinforcement. This proposal was substantiated and extended to a number of representative hallucinogenic agents. d-Amphetamine or chlorpormazine reduced the rate of FR responding without provoking an obvious pause. Examination of tolerance and cross-tolerance to the hallucinogenic pause in the FR pattern after LSD, mescaline, psilocybin, DOM, and DMT generally indicated interactions between the drugs, although this was not entirely consistent. It follows that the mechanisms of action of these drugs probably have elements in common, though they are not necessarily identical. In doses as small as 10 mg/kg, cinanserin, a serotonergic receptor-blocking agent, completely reversed the pause in FR pattern induced by the various hallucinogenic drugs.

Adaptation, Psychological↗
PubMed1975

[Application of group psychology of animals into pharmacological studies. 12. Specificities of actions of psychotropic drugs on emotional and exploratory behaviors of a single mouse or groups of 2 or 3 animals].

The exploratory movement recorder of Tokyo University of Education type was utilized to assess the exploratory motor activity of groups of 1, 2 and 3 mice of the dd-strain. As the animals were observed during 15 min periods to move spontaneously, psychotropic drugs were administered and the specific actions of these agents were determined. Each drug was given i.p. in a dose which proved non-effective in a single mouse. Observations were as follows: The ratio of exploratory motor activity of each pair of mice as compared to a single mouse was not always different from that of control animals. When a 3rd mouse was added to the pair, the motor activity either increased or decreased considerably. The rate of increase in motor activity was calculated 45 min after caffeine, pentetrazol, ephedrine and DL-amphetamine and was found to be less than in the control animals. After administration of chlordiazepoxide, diazepam, imipramine, chlorpromaxine or mescaline, the rate of increase in motor activity was considerably greater than in the controls. With dimorphoramine or hexobarbital, the rate was much the same as control. After beta-oxy gamma-aminobutyric acid, the rate was slightly increased and with diphenhydramine the rate was slightly less than control. Thus the exploratory motor activity of 3 mice as compared to that of 2, decreased considerably after administration of psychotropic stimulants, while after psychotropic depressants, an even greater increase was observed. We have already reported on the mutual relation of mice in fighting episodes and E1-mice convulsions. Those relations were, however, responses elicited by the physical stimulation. In contrast, the mutual relation in this paper is more of a natural nature. In view of observations in this paper, it is considered that CNS stimulants increase the mutual, emotional, checking behavior in groups of 3 animals while CNS depressants decrease the checking behavior. Such behavior is one example of the emotional conduct when a 3rd party is added to a 2 member group.

Animals↗
PubMedDate not supplied

[Neurological syndromes associated with the ingestion of plants and fungi with a toxic component (II). Hallucinogenic fungi and plants, mycotoxins and medicinal herbs].

INTRODUCTION: A wide range of fungi and medicinal herbs, rich in hallucinogenic substances and widely used for mystic and medicinal purposes, can give rise to neurotoxic symptoms. DEVELOPMENT: We review the toxic syndromes that can arise from the ingestion of hallucinogenic fungi, cacti and plants, together with descriptions of cases of acute poisoning resulting from the use of medicinal herbs and from foodstuffs that are contaminated by mycotoxins. A series of different psychedelic fungi belonging to the Psilocybe, Panaeolus and Stropharia genera contain hallucinogenic alkaloids such as psilocybin. Some of the most notable plants displaying hallucinogenic and sedative properties are Papaver somniferum, Erytroxylum sp. and Cannabis sativa. Infusions of ayahuasca are obtained from the lianas and roots of different plants with psychoactive properties, such as Banisteriopsis caapi and Psychotria viridis, which contain alkaloids derived from tryptamine and from the beta carboline harmala. Peyote, a cactus rich in mescaline, and Claviceps purpurea (a fungus rich in LSD) are strong hallucinogens. We also examine ergotism and mycotoxicosis from Arthrinium sp. Poisoning from mycotoxin containing moulds on sugar cane can give rise to encephalopathy and late dystonia. Some of the more noteworthy medicinal plants for which neurological toxicity has been reported are Hypericum perforatum, kava kava (Piper methysticum), Aconitum sp. and Callilepis laureola. CONCLUSIONS: Because of the increasingly more widespread consumption of herbs and fungi and their potentially neurotoxic effects, in clinical practice there is a need to be aware of the neurological syndromes deriving from their use.

Administration, Oral↗
PubMed1992

Pharmacological profile of the new potent neuroleptic ocaperidone (R 79,598).

Ocaperidone, a new benzisoxazolyl piperidine neuroleptic, was compared with haloperidol, risperidone and ritanserin in a large series of pharmacological tests. Ocaperidone inhibited dopamine agonist (apomorphine, amphetamine or cocaine)-induced behavioral effects at low doses (0.014-0.042 mg/kg) and was, thereby, equipotent with haloperidol (0.016-0.024 mg/kg) and 2.0 to 8.3 times more potent than risperidone. Ocaperidone completely blocked the dopamine agonist behavior at slightly higher doses (0.064 mg/kg) and was, thereby, more potent and efficacious than haloperidol (0.097-0.13 mg/kg) and risperidone (0.59-1.17 mg/kg). The dissociation between inhibition of apomorphine behavior and induction of catalepsy was as high for ocaperidone (22) as for risperidone (20) and higher than for haloperidol (8), suggesting risperidone-like low extrapyramidal side effect liability. Ocaperidone also antagonized serotonin agonist (tryptamine, mescaline or 5-hydroxytryptophan)-induced behavioral effects (0.011-0.064 mg/kg) and was, thereby, equipotent with risperidone (0.014-0.056 mg/kg) and at least as potent as ritanserin (0.037-0.13 mg/kg). Ocaperidone displayed its serotonin and dopamine antagonism at the same dose levels, in contrast to risperidone, which was a predominant serotonin antagonist. Apart from protection from compound 48/80 lethality (0.042 mg/kg) and norepinephrine lethality (0.097 mg/kg), which were not considered to hinder its clinical application, no additional secondary effects were observed at low doses of ocaperidone. In the apomorphine test in dogs, ocaperidone was very potent (i.v., s.c. and p.o. ED50 values: less than 1.0 micrograms/kg) and showed a rapid onset (less than 0.5 h) and long duration of action (24 h) after p.o. administration. Ocaperidone is concluded to be a highly potent and efficacious dopamine-D2 antagonist with concomitant, equivalent serotonin 5-HT2 antagonism. Ocaperidone is expected to exert pronounced haloperidol-like effects on the positive symptoms of schizophrenic patients but with risperidone-like low extrapyramidal side effect liability and improved patient compliance.

Animals↗
PubMed1992

Biochemical and pharmacological properties of SR 46349B, a new potent and selective 5-hydroxytryptamine2 receptor antagonist.

A new potent, selective and p.o. active serotonergic [5-hydroxytryptamine (5-HT2)] receptor antagonist, SR 46349B [trans, 4-([3Z)3-(2-dimethylaminoethyl)oxyimino-3(2-flurophenyl++ +)propen-1-yl]phenol hemifumarate) has been characterized by a series of "in vitro" and "in vivo" methods. Based upon binding studies with 5-HT2 receptors in rat brain cortical membranes and blockade of 5-HT-induced contractions in isolated tissues (rabbit thoracic aorta, rat jugular vein, rat caudal artery, rat uterus and guinea pig trachea), SR 46349B showed high affinity for 5-HT2 receptors. Furthermore, SR 46349B displayed moderate affinity for the 5-HT1C receptor and had no affinity for the other 5-HT1 subclass (5-HT1A, 5-HT1B or 5-HT1D), dopamine (D1 or D2), "alpha" adrenergic (alpha-1 or alpha-2), sodium and calcium channel and histamine (H1) receptors. It did not interact with histamine (H1), alpha-1 adrenergic and 5-HT3 receptors in smooth muscle preparations. No inhibition of the uptake of norepinephrine, dopamine or 5-HT was seen. Based upon blockade of pressor responses to 5-HT in pithed rats and in vivo binding studies in mice, SR 46349B was found to be a potent and p.o. active 5-HT2 receptor antagonist with a relatively long duration of action. Behavioral experiments, including mescaline- and 5-hydroxytryptophan-induced head twitches and learned helplessness, as well as sleep-waking cycle and EEG spectral parameter studies, indicated that SR 46349B has a classical 5-HT2 psychopharmacological antagonist profile.

Animals↗
PubMed1977

Further evaluation of the discriminative effects of morphine in the rat.

Rats were trained in a two-choice discrete trial avoidance paradigm to discriminate between saline and 3.0 mg/kg of morphine. Behavior was considered to be under stimulus ocntrol when the rats completed at least 90% of the trials in a 20-trial session on the morphine-appropriate choice lever after receiving morphine and when they completed at least 90% of the trials on the saline-appropriate choice lever after receiving saline. The discriminative effects of morphine, measured by responding on the morphine-appropriate lever, were then evaluated by determining the dose-response characteristics of representative narcotic analgesics, analgesics with mixed agonist and narcotic antagonist properties and nonopioid psychoactive drugs. Eight narcotic analgesics each produced dose-related responding on the morphine-appropriate lever. The relative potency for producing discriminative effects equivalent to those produced by 3.0 mg/kg of morphine ranged form etonitazene = 1000 x morphine to propoxyphene = 0.0175 x morphine. Of the narcotic antagonist analgesics tested, butorphanol and nalmexone produced discriminative effects equivalent to those of the morphine training dose whereas nalorphine, levallorphan, oxilorphan, nalbuphine and ketocyclazocine did not. The nonopioid psychoactive drugs, mescaline, ketamine, physostigmine and scopolamine, also failed to produce discriminative effect equivalent to those produced by 3.0 mg/kg of morphine. These results confirm and extend our previous findings that of those drugs which have also been evaluated in man, discriminative effects equivalent to the training dose of morphine are produced uniquely by narcotic analgesics and narcotic antagonists which produce morphine-like subjective effects. These results are compatible with the hypothesis that the properties of morphine which enable it to function as a discriminative stimulus in the rat are analogous to those responsible for producing subjective effects in man.

Analgesics↗
PubMedDate not supplied

[3,4-methylenedioxymethamphetamine ('ecstasy'): its long-term emotional and cognitive effects, and serotonin depletion].

AIMS: The main objective of this study is to describe the different neuropsychological deficits associated to the consumption of 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy'), as well as the growing evidence that attributes these deficits to the selective axonal damage to serotoninergic cells brought about by this substance. DEVELOPMENT: MDMA is an amphetamine derivative that, like its precursor, has properties as a stimulant. Part of its chemical structure is similar to that of the hallucinogen mescaline with which it shares the capacity to alter perception. Nevertheless, the primary pharmacological effect of this substance, which is what usually leads to its use and abuse, is chiefly linked to an intense positive emotional state. This effect on the individual's mood is also usually accompanied by numerous feelings of empathy, sociability and closeness, which turn this drug into a powerful entactogenic agent (a term used in psychotherapy to describe a state of wellbeing, closeness and emotional self-awareness produced by certain compounds). The antidepressant and entactogenic effects induced by an acute dose of MDMA can be accounted for by the notable increase in serotonin bioavailability triggered by the drug. Repeated consumption of MDMA, however, ends up affecting many functions that have been related to the serotoninergic systems, such as sleep, appetite, attention and memory, or one's emotional state. CONCLUSIONS: Most of the neuropsychological disorders found in individuals who take ecstasy on a regular basis can be explained by the selective neurodegeneration processes that the drug appears to produce in the serotonin terminals of the brain in the long run.

Animals↗