Cannabis sativa is the source of a unique set of compounds known collectively as plant cannabinoids or phytocannabinoids. This review focuses on the manner with which three of these compounds, (-)-trans-delta9-tetrahydrocannabinol (delta9-THC), (-)-cannabidiol (CBD) and (-)-trans-delta9-tetrahydrocannabivarin (delta9-THCV), interact with cannabinoid CB1 and CB2 receptors. Delta9-THC, the main...
Background and purpose: Illegal ‘ecstasy’ tablets frequently contain 3,4‐methylenedioxymethamphetamine (MDMA)‐like compounds of unknown pharmacological activity. Since monoamine transporters are one of the primary targets of MDMA action in the brain, a number of MDMA analogues have been tested for their ability to inhibit [ 3 H]noradrenaline uptake into rat PC12 cells expressing the...
Previous work implied that the hippocampal cannabinoid system was particularly important in some forms of learning, but direct evidence for this hypothesis is scarce. We therefore assessed the effects of the synthetic cannabinoid HU210 on memory and hippocampal activity. HU210 (100 microg kg(-1)) was administered intraperitoneally to rats under three experimental conditions. One group of...
Background and purpose: Studies were designed to examine the effects of dietary fats on metabolic effects of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy). These effects included hyperthermia, expression of uncoupling protein (UCP1 and 3) in brown adipose tissue or skeletal muscle and plasma free fatty acid (FFA) levels. Experimental approach: Male Sprague-Dawley rats were fed either a...
To follow up in vitro evidence that Delta(9)-tetrahydrocannabivarin extracted from cannabis (eDelta(9)-THCV) is a CB(1) receptor antagonist by establishing whether synthetic Delta(9)-tetrahydrocannabivarin (O-4394) and Delta(8)-tetrahydrocannabivarin (O-4395) behave as CB(1) antagonists in vivo. O-4394 and O-4395 were compared with eDelta(9)-THCV as displacers of [(3)H]-CP55940 from specific...
3,4‐Methylenedioxymethamphetamine (MDMA or ‘ecstasy’) decreases the 5‐HT concentration, [ 3 H]‐paroxetine binding and tryptophan hydroxylase activity in rat forebrain, which has been interpreted as indicating 5‐HT neurodegeneration. This has been questioned, particularly the 5‐HT loss, as MDMA can also inhibit tryptophan hydroxylase. We have now evaluated the validity of these parameters as a...
The effects of injection of 3,4‐methylenedioxymethamphetamine (MDMA), 3,4‐methylenedioxyamphetamine (MDA) and N ‐ethyl‐3,4‐methylenedioxyamphetamine (MDEA) (all 20 mg kg −1 ) on blood pressure, heart rate, core body temperature and locomotor activity in conscious rats were investigated using radiotelemetry. MDMA and MDA produced a prolonged increase in both systolic and diastolic pressures,...
3,4‐Methylenedioxymetamphetamine (MDMA) produces complex effects on body temperature, including hypo‐ and hyperthermic components that vary with ambient temperature and strain of rat. We have previously reported that MDMA is an α 2 ‐adrenoceptor agonist, and α 2 ‐adrenoceptor agonists such as clonidine produce hypothermia. The purpose of this study was to investigate the effects of MDMA on core...
3,4‐Methylenedioxymethamphetamine (MDMA, ‘ecstasy’) administration to rats produces hyperthermia if they are housed in normal or warm ambient room temperature ( T a ) conditions (20°C), but hypothermia when in cool conditions ( T a 17°C). We have now investigated some of the mechanisms involved. MDMA (5 mg kg −1 i.p.) produced a rapid decrease in rectal temperature in rats at T a 15°C. This...
This study investigated whether the immediate and long‐term effects of 3,4‐methylenedioxymethamphetamine (MDMA) on monoamines in mouse brain are due to the parent compound and the possible contribution of a major reactive metabolite, 3,4‐dihydroxymethamphetamine (HHMA), to these changes. The acute effect of each compound on rectal temperature was also determined. MDMA given i.p. (30 mg kg −1 ,...
The reward circuitry of the brain consists of neurons that synaptically connect a wide variety of nuclei. Of these brain regions, the ventral tegmental area (VTA) and the nucleus accumbens (NAc) play central roles in the processing of rewarding environmental stimuli and in drug addiction. The psychoactive properties of marijuana are mediated by the active constituent, Delta(9)-THC, interacting...
Studies were designed to examine the effects of α 1 ( α 1 AR)‐ plus β 3 ‐adrenoreceptor ( β 3 AR) antagonists on 3,4‐methylenedioxymethamphetamine (MDMA, Ecstasy)‐induced hyperthermia and measures of rhabdomyolysis (creatine kinase (CK)) and renal function (blood urea nitrogen (BUN) and serum creatinine (sCr)) in male Sprague–Dawley rats. MDMA (40 mg kg −1 , s.c.) induced a rapid and robust...
1. We recently described that several 2-(2,5-dimethoxy-4-substituted phenyl)ethylamines (PEAs), including 4-I=2C-I, 4-Br=2C-B, and 4-CH(3)=2C-D analogs, are partial agonists at 5-HT(2C) receptors, and show low or even negligible intrinsic efficacy at 5-HT(2A) receptors. These results raised the proposal that these drugs may act as 5-HT(2) antagonists. 2. To test this hypothesis, Xenopus laevis...
Little is known about the cellular effects induced by 3,4‐methylenedioxymethamphetamine (MDMA, ecstasy), although changes in gene expression have been observed following treatments with other psychostimulants. Thus, the aim of this study was to investigate in mice, the relationships between the ras‐dependent protein kinase ERK and MDMA‐induced reinforcement using the conditioned place...
I.c.v. self‐administration of MDMA (0.01–2 μg per infusion), alone and in combination with CP 55,940 (0.4 μg infusion −1 ), was studied on an operant responding procedure. On the basis of individual preference for one of two levers, developed during training, rats were allowed to self‐administer vehicle from the preferred lever and MDMA from the other. Pressings on the MDMA associated‐lever,...
The pharmacological profile of a series of (+/-)-2,5-dimethoxy-4-(X)-phenylisopropylamines (X=I, Br, NO(2), CH(3), or H) and corresponding phenylethylamines, was determined in Xenopus laevis oocytes injected with cRNA coding for rat 5-HT(2A) or 5-HT(2C) receptors. The efficacy and relative potency of these drugs were determined and compared to classical 5-HT(2) receptor agonists and...
1. The molecular nature and functions of the I(2) subtype of imidazoline binding sites are unknown but evidence suggests an association with monoamine oxidase (MAO). Rats can distinguish the selective imidazoline I(2)-site ligand 2-BFI from vehicle in drug discrimination, indicating functional consequences of occupation of these sites. We have used drug discrimination to investigate the nature...
Methylenedioxymethamphetamine (MDMA, “ecstasy”), widely used as a recreational drug, can produce hyponatraemia. The possibility that this could result from stimulation of vasopressin by MDMA or one of its metabolites has been investigated in vitro . Release of both oxytocin and vasopressin from isolated hypothalami obtained from male Wistar rats was determined under basal conditions and...
The pharmacology of the acute hyperthermia that follows 3,4‐methylenedioxymethamphetamine (MDMA, ‘ecstasy’) administration to rats has been investigated. MDMA (12.5 mg kg −1 i.p.) produced acute hyperthermia (measured rectally). The tail skin temperature did not increase, suggesting that MDMA may impair heat dissipation. Pretreatment with the 5‐HT 1/2 antagonist methysergide (10 mg kg −1 ), the...
Administration of 3,4‐methylenedioxymethamphetamine (MDMA, ‘ecstasy’) to mice produces acute hyperthermia and long‐term degeneration of striatal dopamine nerve terminals. Attenuation of the hyperthermia decreases the neurodegeneration. We have investigated the mechanisms involved in producing the neurotoxic loss of striatal dopamine. MDMA produced a dose‐dependent loss in striatal dopamine...
It has been reported that co‐administration of fluoxetine with 3,4‐methylenedioxymethamphetamine (MDMA, ‘ecstasy’) prevents MDMA‐induced degeneration of 5‐HT nerve endings in rat brain. The mechanisms involved have now been investigated. MDMA (15 mg kg −1 , i.p.) administration produced a neurotoxic loss of 5‐HT and 5‐hydroxyindoleacetic acid (5‐HIAA) in cortex, hippocampus and striatum and a...
We have investigated the effects of methylenedioxymethamphetamine (MDMA, ‘ecstasy’), i.v., on diastolic blood pressure (DBP) in pithed and pentobarbitone anaesthetized rats. In pithed rats, the non‐selective 5‐HT receptor antagonist methiothepin (0.1 mg kg −1 ) and the α 2 ‐adrenoceptor antagonists methoxyidazoxan and yohimbine (1 mg kg −1 ) showed significant α 1 ‐adrenoceptor antagonist...
1. Phencyclidine (PCP) is widely used as an animal model of schizophrenia. The aim of this study was to better understand the role of nitric oxide (NO) in the mechanism of action of PCP and to determine whether positive NO modulators may provide a new approach to the treatment of schizophrenia. 2. The effects of the NO donor, sodium nitroprusside (SNP), were studied in PCP-treated rats....
Ibogaine and 18-methoxycoronaridine are naturally occurring alkaloids reported to possess antiaddictive properties in several models of drug dependence. We have examined their effect at mu-opioid receptors regulating neurogenic contractions of several smooth muscle preparations and also against spontaneous contractions of the rat isolated portal vein. Ibogaine (pIC(50) 5.28) and...
We have investigated the effects of methylenedioxymethamphetamine (MDMA, ‘ecstasy’) on peripheral noradrenergic neurotransmission in the rat. In rat atrial slices pre‐incubated with [ 3 H]‐noradrenaline and in the presence of desipramine (1 μ M ) to prevent effects of MDMA on basal outflow of tritium, MDMA (10 μ M ) significantly inhibited the release of tritium evoked by short trains of six...