Acute DOB and PMA Administration Impairs Motor and Sensorimotor Responses in Mice and Causes Hallucinogenic Effects in Adult Zebrafish

The drastic increase in hallucinogenic compounds in illicit drug markets of new psychoactive substances (NPS) is a worldwide threat. Among these, 2, 5-dimetoxy-4-bromo-amphetamine (DOB) and paramethoxyamphetamine (PMA; marketed as "ecstasy") are frequently purchased on the dark web and consumed for recreational purposes during rave/dance parties. In fact, these two substances seem to induce the same effects as MDMA, which could be due to their structural similarities. According to users, DOB and PMA share the same euphoric effects: increasing of the mental state, increasing sociability and empathy. Users also experienced loss of memory, temporal distortion, and paranoia following the repetition of the same thought. The aim of this study was to investigate the effect of the acute systemic administration of DOB and PMA (0.01-30 mg/kg; i.p.) on motor, sensorimotor (visual, acoustic, and tactile), and startle/PPI responses in CD-1 male mice. Moreover, the pro-psychedelic effect of DOB (0.075-2 mg/kg) and PMA (0.0005-0.5 mg/kg) was investigated by using zebrafish as a model. DOB and PMA administration affected spontaneous locomotion and impaired behaviors and startle/PPI responses in mice. In addition, the two compounds promoted hallucinatory states in zebrafish by reducing the hallucinatory score and swimming activity in hallucinogen-like states

Design and characterization of superpotent bivalent ligands targeting oxytocin receptor dimers via a channel-like structure

Dimeric/oligomeric states of G-protein coupled receptors have been difficult to target. We report here bivalent ligands consisting of two identical oxytocin-mimetics that induce a three order magnitude boost in G-protein signaling of oxytocin receptors (OTRs) in vitro and a 100- and 40-fold gain in potency in vivo in the social behavior of mice and zebrafish. Through receptor mutagenesis and interference experiments with synthetic peptides mimicking transmembrane helices (TMH), we show that such superpotent behavior follows from the binding of the bivalent ligands to dimeric receptors based on a TMH1-TMH2 interface. Moreover, in this arrangement, only the analogues with a well-defined spacer length (∼25 Å) precisely fit inside a channel-like passage between the two protomers of the dimer. The newly discovered oxytocin bivalent ligands represent a powerful tool for targeting dimeric OTR in neurodevelopmental and psychiatric disorders and, in general, provide a framework to untangle specific arrangements of G-protein coupled receptor dimers

Epileptiform Activity and Cognitive Deficits in SNAP-25+/− Mice are Normalized by Antiepileptic Drugs

Synaptosomal-associated protein of 25 kDa (SNAP-25) is a protein that participates in the regulation of synaptic vesicle exocytosis through the formation of the soluble NSF attachment protein receptor complex and modulates voltage-gated calcium channels activity. The Snap25 gene has been associated with schizophrenia, attention deficit hyperactivity disorder, and bipolar disorder, and lower levels of SNAP-25 have been described in patients with schizophrenia. We used SNAP-25 heterozygous (SNAP-25+/−) mice to investigate at which extent the reduction of the protein levels affects neuronal network function and mouse behavior. As interactions of genotype with the specific laboratory conditions may impact behavioral results, the study was performed through a multilaboratory study in which behavioral tests were replicated in at least 2 of 3 distinct European laboratories. Reductions of SNAP-25 levels were associated with a moderate hyperactivity, which disappeared in the adult animals, and with impaired associative learning and memory. Electroencephalographic recordings revealed the occurrence of frequent spikes, suggesting a diffuse network hyperexcitability. Consistently, SNAP-25+/− mice displayed higher susceptibility to kainate-induced seizures, paralleled by degeneration of hilar neurons. Notably, both EEG profile and cognitive defects were improved by antiepileptic drugs. These results indicate that reduction of SNAP-25 expression is associated to generation of epileptiform discharges and cognitive dysfunctions, which can be effectively treated by antiepileptic drug

Endovanilloid and endocannabinoid mechanism in neuroprotection

Exogenous and endogenous cannabinoids exert neuroprotection either in vitro or in vivo under different experimental conditions. Thus, cannabinoid receptor activation protects hippocampal or granule cerebellar neurons from excitotoxicity (Skaper et al., 1996; Shen and Thayer,1998; Hampson and Grimaldi, 2001), from hypoxia and glucose deprivation (Nagayama et al., 1999), from acute brain trauma (Panikashvili et al., 2001), ouabain-induced neurotoxicity (van der Stelt et al., 2001) and oxidative cell death (Kim et al., 2005). The size of cerebral infarcts after middle cerebral artery occlusion is increased in CB1-knockout mice (Parmentier-Batteur et al., 2002).The protective effect has been ascribed to inhibition of glutamate transmission, reduction of Ca++ influx and subsequent inhibition of noxious cascades, such as tumor necrosis factor-a (TNF-a) generation and oxidative stress (van der Stelt et al., 2002). More recently, exogenous 2-arachidonoylglycerol (2-AG) has been found to reduce brain edema, infarct volume and hippocampal death after closed head injury (Panikashvili et al., 2005), in part via CB1 receptor\u2013mediated mechanism. However, cannabinoid CB1 receptor activation does not prevent the toxicity of glutamate towards embryonic chick telencephalon primary cultures (Nilsson et al., 2003). Increased production of endocannabinoid-related compounds modulate the inflammatory response to ischemia (Franklin et al., 2003). Therefore, endogenous cannabinoid signaling mechanisms may represent a key component of protection and repair programs mobilized in the injured brain. On the other hand, in addition to the CB1 receptor, the endocannabinoid N-arachidonoylethanolamine (AEA) or its metabolites may convey neuroprotection via other molecular targets (Grotenhermen, 2004). AEA is also a full agonist at the transient receptor potential channel vanilloid subfamily member 1 (VR1), recently reported to be involved in neurodegeneration. It is present in regions highly susceptible to neurodegenerative insults and it is influenced by temperature and pH changes (Mezey et al., 2000; Marinelli et al., 2002). In addition, during brain injury, AEA and lipoxigenase products accumulate in the brain (Marinelli et al., 2000, Muthian et al., 2004). Capsazepine, the selective VR1 vanilloid antagonist, has been shown to protect against neuronal injury caused by oxygen glucose deprivation by inhibiting I (h) (Veldhuis et al., 2003). A role of vanilloid receptors and lipoxygenases in neuroprotection by AEA and arvanil against in vivo excitotoxicity in the rat, has been reported (Ray et al., 2003) and a protective role of cannabinoid receptors against apoptosis induced by AEA vai vanilloid receptors(Maccarrone et al., 2000). Here we report the results recently obtained after acute post-ischemic treatment of different exogenous cannabinods agonists (CP 55,940, Cannabidiol, D9-tetrahydrocannabidiol (D9-THC), CB1 cannabinoid receptor antagonists (SR 141716), VR1 vanilloid receptor agonists (Capsaicin) or antagonists (Capsazepine) in a model of transient global cerebral ischemia in Mongolian gerbils. The neuroprotection was quantified in terms of complete recovery of EEG total and relative spectral power, spontaneous motor activity, memory function and hippocampal CA1 neuronal density, starting from 1 to 7 days. All the compounds protected against ischemia-induced EEG flattening, hyperlocomotion and memory impairment with a dose-dependent bell-shaped curve. In addition, a survival of hippocampal neurons was obtained. From the present lecture it can be concluded that there is a considerable experimental evidence for a neuroprotective role of both CB1 and VR1 cannabinoid and vanilloid receptors. However, the activation of both receptors does not completely explain the neuroprotective effect observed during brain injury. The data are critically reviewed and possible explanations are given

Electronic nicotine delivery systems (ENDS): A convenient means of smoking?

Electronic nicotine delivery systems (ENDS), which are becoming increasingly popular in many parts of the world, have recently become more sophisticated in terms of their more active content and better controlled vaporisation. This review begins by describing how cigarette smoking led to the development of ENDS as a means of combatting nicotine addiction. ENDS are usually categorised as belonging to one of only three main generations, but a fourth has been added in order to differentiate the latest, most powerful, most advanced and innovative that have improved heating efficiency. Descriptions of the principal substances contained in ENDS are followed by considerations concerning the risk of toxicity due to the presence of albeit low concentrations of such a variety of compounds inhaled over a long time, and the increasingly widespread use of ENDS as a means of smoking illicit drugs. We also review the most widely used pharmacotherapeutic approaches to smoking cessation, and recent epidemiological data showing that ENDS can help some people to stop smoking. However, in order to ensure their appropriate regulation, there is a need for higher-quality evidence concerning the health effects and safety of ENDS, and their effectiveness in discouraging tobacco smoking

The Non-Peptide Arginine-Vasopressin v1a Selective Receptor Antagonist, SR49059, Blocks the Rewarding, Prosocial, and Anxiolytic Effects of 3,4-Methylenedioxymethamphetamine and Its Derivatives in Zebra Fish

3,4-Methylenedioxymethamphetamine (MDMA) and its derivatives, 2,5-dimethoxy-4-bromo-amphetamine hydrobromide (DOB) and para-methoxyamphetamine (PMA), are recreational drugs whose pharmacological effects have recently been attributed to serotonin 5HT2A/C receptors. However, there is growing evidence that the oxytocin (OT)/vasopressin system can modulate some the effects of MDMA. In this study, MDMA (2.5–10 mg/kg), DOB (0.5 mg/kg), or PMA (0.005, 0.1, or 0.25 mg/kg) were administered intramuscularly to adult zebra fish, alone or in combination with the V1a vasopressin antagonist, SR49059 (0.01–1 ng/kg), before carrying out conditioned place preference (CPP), social preference, novel tank diving, and light–dark tests in order to evaluate subsequent rewarding, social, and emotional-like behavior. The combination of SR49059 and each drug progressively blocked: (1) rewarding behavior as measured by CPP in terms of time spent in drug-paired compartment; (2) prosocial effects measured on the basis of the time spent in the proximity of a nacre fish picture; and (3) anxiolytic effects in terms of the time spent in the upper half of the novel tank and in the white compartment of the tank used for the light–dark test. Antagonism was obtained at SR49059 doses which, when given alone, did not change motor function. In comparison with a control group, receiving vehicle alone, there was a three to five times increase in the brain release of isotocin (the analog of OT in fish) after treatment with the most active doses of MDMA (10 mg/kg), DOB (0.5 mg/kg), and PMA (0.1 mg/kg) as evaluated by means of bioanalytical reversed-phase high-performance liquid chromatography. Taken together, these findings show that the OT/vasopressin system is involved in the rewarding, prosocial, and anxiolytic effects of MDMA, DOB, and PMA in zebra fish and underline the association between this system and the behavioral alterations associated with disorders related to substance abuse

Neuroprotective Effects of Genistein in Mongolian Gerbils: Estrogen Receptor-β Involvement

Genistein is a naturally occurring plant-derived phytoestrogen, present in the human diet, known to possess some beneficial effects. The present study investigated the effect of genistein on neuroprotection evaluated through electroencephalographic and behavioural correlates in a model of global cerebral ischemia in gerbils. Over the dose range tested, genistein (3 and 10 mg/ kg), given 5 min after recirculation antagonized the ischemia-induced electroencephalographic total spectral power decrease 7 days after ischemia; fully prevented ischemia-induced hyperlocomotion evaluated 1 day after ischemia; reversed ischemia-induced memory impairment evaluated through both nest building behaviour and object recognition test; decreased malondialdehyde overproduction in the brain, evaluated 7 days after reperfusion; and fully promoted the survival of pyramidal cells in the CA1 hippocampal subfield. The selective antagonist for estrogen receptor–β (ERβ), 4-[2-phenyl-5,7-bis(trifluoromethyl) pyrazolo[1,5-a]pyrimidin-3-yl]phenol (PHTPP) given 30 min before carotid occlusion, fully prevented the neuroprotective effect of genistein at the dose of 3 mg/kg. These results demonstrate the neuroprotective effect of genistein through the activation of ERβ and provide further grounds for the growing interest concerning the true potential of phytoestrogens as compounds to beneficially affect brain injury without having the disadvantages of estrogens. Keywords:: ischemia, electroencephalography (EEG), phytoestrogen, CA1, estrogen receptor–

Neuroprotection induced by delta-9-THC in a model of transient global cerebral ischemia

There is increasing experimental evidence of a neuroprotective effect of cannabinoids in experimental models including ischemia (Nagayama et al. 1999; Braida et al. 2000, 2003; van der Stelt et al., 2001a, 2001b; Veldhuis et al., 2003; Marsicano et al., 2003) and head trauma (Panikashvli et al., 2001). D9-THC, the major and psychoactive constituent of marijuana, is known to exert protective actions either in vitro, in rat cortical neurons (Hampson et al., 1998), or in vivo, in a model of rat forebrain ischemia (Louw et al., 2000) and neurotoxicity (van der Stelt et al., 2001; El-Remessy et al., 2003). However the role of CB1 cannabinoid receptor on D9-THC -induced neuroprotection is still controversial since partial (El-Remessy et al., 2003) or any (Hampson et al., 1998; van der Stelt et al., 2001) antagonism was found. The aim of the present work was to further investigate in vivo the effect of post-ischemic treatment with D9-THC on transient global cerebral ischemia in gerbils using a wide range of doses (0.05 \u2013 2 mg/kg) and to evaluate the role of CB1 cannabinoid receptor using the selective CB1 cannabinoid antagonist SR 141716. Gerbils, previously submitted to bilateral carotid occlusion for 10 min, were treated with D9-THC 5 min after recirculation and monitored for 7 days. Electroencephalographic (EEG) mean total spectral power (on Day 7), spontaneous motor activity (on Day 1) and cognitive function (on Day 3), were evaluated as parameters known to be hardly influenced by cerebral ischemia. D9-THC protected against ischemia-induced EEG flattening and hyperlocomotion, evaluated in an activity cage, with a dose-dependent bell-shaped curve, the maximal active dose being 1 mg/kg. Ischemia-induced memory impairment, evaluated through the passive avoidance test was blocked by D9-THC from 0.5 to 2 mg/kg. Preliminary results indicate that the neuroprotection by D9-THC is in part mediated by the cannabinoid receptor CB1

Effect of the anandamide transporter inhibitor,AM404, on anxiety response in rats

There are many and contradictory reports on the interaction between cannabinoids and anxiety. Both cannabinoid agonists and antagonists have been shown to have anxiolytic- and anxiogenic-like behavioural reactions in rodents depending on the dose and the context (Onaivi et al. 1990; Crawley et al. 1993; Onaivi et al. 1995; Rodriguez de Fonseca, 1996; Navarro et al., 1997; Akinshola et al. 1999; Haller et al., 2002; Berrendero and Maldonado 2002;Valjent et al.. 2002; Haller et al. 2004). The aim of the present work was to further elucidate the role of endocannabinoid system in anxiety response. For this purpose, the anandamide transport inhibitor, AM 404 (2.5-10 mg/kg), and D9\u2013THC (0.015-1.5 mg/kg), previously evaluated in our laboratory for its reinforcing properties in a Conditioned Place Preference test (Braida et al., 2005), were studied in a plus-maze apparatus according to Pellow et al. (1985) The test length was 5 min and the total time spent in each arm and the number of arm entries were scored by trained observers in male Sprague-Dawley rats, 30 min after treatment. The role of the CB1 cannabinoid and opioid receptor was investigated pre-treating rats with SR 141716 (0.25-1 mg/kg) and naloxone (0.5-2 mg/kg), 10 min before D9\u2013THC or AM 404. Both D9\u2013THC (0.75 mg/kg) and AM 404 (10 mg/kg) significantly elevated the percentage of open arm entries and the time spent in the open arms, showing an anxiolytic activity. This effect was reversed by pre-treatment with SR 141716. An interaction with opioid system was also found. These findings further support a key role of endocannabinoid system in the regulation of emotional states