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Addiction Biology May 2022Levamisole is a veterinary anthelmintic drug and a common adulterant of misused drugs. This study analyses the lethal, antinociceptive and haematological effects...
Levamisole is a veterinary anthelmintic drug and a common adulterant of misused drugs. This study analyses the lethal, antinociceptive and haematological effects produced by acute or repeated levamisole administration by itself or combined with morphine. Independent groups of male Swiss Webster mice were i.p. injected with 100 mg/kg morphine, 31.6 mg/kg levamisole (lethal doses at 10%, LD ) or the same doses combined. Naloxone pretreatment (10 mg/kg, i.p.) prevented morphine-induced death, as did 2.5 mg/kg, i.p. mecamylamine with levamisole. Co-administration of levamisole and morphine (Lvm + Mor) increased lethality from 10% to 80%. This augmented effect was prevented by 30 mg/kg, i.p. naloxone and reduced with 10 mg/kg naloxone plus 2.5 mg/kg, i.p. mecamylamine. In independent groups of mice, 17.7 mg/kg, i.p. levamisole antagonized the acute morphine's antinociceptive effect evaluated in the tail-flick test. Repeated 17.7 mg/kg levamisole administration (2×/day/3 weeks) did not affect tolerance development to morphine (10 mg/kg, 3×/day/1 week). Blood samples obtained from mice repeatedly treated with levamisole showed leukopenia and neutropenia. Morphine also produced neutropenia, increased erythrocyte count and other related parameters (e.g. haemoglobin). Lvm + Mor had similar effects on leukocyte and neutrophil counts to those seen with levamisole only, but no erythrocyte-related alterations were evident. Blood chemistry analysis did not indicate liver damage but suggested some degree of electrolyte balance impairment. In conclusion, Lvm + Mor increased death risk, altered morphine-induced antinociceptive effects and produced haematologic abnormalities. The importance of studying combinations of drugs of abuse lies in the fact that drug users frequently combine drugs, which are commonly adulterated.
Topics: Analgesics; Animals; Levamisole; Male; Mecamylamine; Mice; Morphine; Naloxone; Neutropenia
PubMed: 35470549
DOI: 10.1111/adb.13166 -
European Journal of Pharmacology Oct 2015In this study we aimed to test central administration of CDP-choline on serum ghrelin, leptin, glucose and corticosterone levels in rats. Intracerebroventricular...
In this study we aimed to test central administration of CDP-choline on serum ghrelin, leptin, glucose and corticosterone levels in rats. Intracerebroventricular (i.c.v.) 0.5, 1.0 and 2.0 µmol CDP-choline and saline were administered to male Wistar-Albino rats. For the measurement of serum leptin and ghrelin levels, blood samples were obtained baseline and at 5, 15, 30, 60 and 120 min following i.c.v. CDP-choline injection. Equimolar doses of i.c.v. choline (1.0 µmol) and cytidine (1.0 µmol) were administered and measurements were repeated throughout the second round of the experiment. Atropine (10 µg) and mecamylamine (50 µg) were injected intracerebroventricularly prior to CDP-choline and measurements repeated in the third round of the experiment. After 1 µmol CDP-choline injection, serum ghrelin levels were suppressed significantly at 60 min (P=0.025), whereas serum leptin levels were increased at 60 and 120 min (P=0.012 and P=0.017 respectively). CDP-choline injections also induced a dose- and time-dependent increase in serum glucose and corticosterone levels. The effect of choline on serum leptin and ghrelin levels was similar with CDP-choline while no effect was seen with cytidine. Suppression of serum ghrelin levels was eliminated through mecamylamine pretreatment while a rise in leptin was prevented by both atropine and mecamylamine pretreatments. In conclusion; centrally injected CDP-choline suppressed serum ghrelin levels while increasing serum leptin levels. The observed effects following receptor antagonist treatment suggest that nicotinic receptors play a role in suppression of serum ghrelin levels,whereas nicotinic and muscarinic receptors both play a part in the increase of serum leptin levels.
Topics: Animals; Atropine; Blood Glucose; Corticosterone; Cytidine Diphosphate Choline; Ghrelin; Injections; Leptin; Male; Mecamylamine; Muscarinic Antagonists; Nicotinic Antagonists; Rats, Wistar; Receptors, Muscarinic; Receptors, Nicotinic
PubMed: 26162700
DOI: 10.1016/j.ejphar.2015.07.014 -
Addiction Biology Mar 2016There are a number of approved therapeutics for the management of alcohol dependence, which might also convey the potential as smoking cessation aids. The present study...
There are a number of approved therapeutics for the management of alcohol dependence, which might also convey the potential as smoking cessation aids. The present study investigated the effect of a few of these therapeutics and potential candidates (non-peptide vasopressin V1b antagonists) on the expression of nicotine-induced behavioral sensitization in Wistar rats. The following compounds were included in this evaluation: rimonabant, bupropion, topiramate, acamprosate, naltrexone, mecamylamine, nelivaptan (SSR-149415, V1b antagonist) and two novel V1b antagonists. Following the development of nicotine-induced locomotor sensitization and a withdrawal period, the expression of sensitization was assessed in the presence of one of the examined agents given 30 minutes prior to the nicotine challenge injection. Acamprosate, naltrexone, rimonabant, mecamylamine, nelivaptan and V1b antagonist 'compound 2' significantly antagonized the expression of nicotine-induced sensitization. Whereas topiramate showed a trend for effects, the V1b antagonist 'compound 1' did not show any significant effects. Bupropion failed to block sensitization but increased activity alone and was therefore tested in development and cross-sensitization studies. Taken together, these findings provide pre-clinical evidence that these molecules attenuated the expression of nicotine-induced sensitization and should be further investigated as putative treatments for nicotine addiction. Moreover, V1b antagonists should be further investigated as a potential novel smoking cessation aid.
Topics: Acamprosate; Analysis of Variance; Animals; Antidiuretic Hormone Receptor Antagonists; Bupropion; Dose-Response Relationship, Drug; Fructose; Indoles; Male; Motor Activity; Naltrexone; Nicotine; Nicotinic Agonists; Pyrrolidines; Rats, Wistar; Taurine; Tobacco Use Cessation Devices; Topiramate
PubMed: 25307867
DOI: 10.1111/adb.12190 -
The Journal of Pharmacology and... Aug 2020Methylenedioxypyrovalerone (MDPV) is an abused synthetic cathinone, commonly referred to as a "bath salt." Because the dopamine (DA) transporter (DAT) and vesicular...
Methylenedioxypyrovalerone (MDPV) is an abused synthetic cathinone, commonly referred to as a "bath salt." Because the dopamine (DA) transporter (DAT) and vesicular monoamine transporter-2 (VMAT-2) are key regulators of both the abuse and neurotoxic potential of structurally and behaviorally related agents, the impact of MDPV on these transporters was investigated. Results revealed that a single in vivo MDPV administration rapidly (within 1 hour) and reversibly increased both rat striatal DAT and VMAT-2 activity, as assessed via [H]DA uptake in synaptosomes and synaptic vesicles, respectively, prepared from treated rats. There was no evidence of an MDPV-induced increase in plasmalemmal membrane DAT surface expression. Plasma concentrations of MDPV increased dose-dependently as assessed 1 hour after 2.5 and 5.0 mg/kg (s.c.) administration and returned to levels less than 10 ng/ml by 18 hours after 2.5 mg/kg (s.c.). Neither pretreatment with a D1 receptor (SCH23390), a D2 receptor (eticlopride), nor a nicotinic receptor (mecamylamine) antagonist attenuated the MDPV-induced increase in DAT activity. In contrast, eticlopride pretreatment attenuated both the MDPV-induced increase in VMAT-2-mediated DA uptake and an associated increase in cytoplasmic-associated vesicle VMAT-2 immunoreactivity. SCH23390 did not attenuate the MDPV-induced increase in VMAT-2 activity. Repeated MDPV injections did not cause persistent DAergic deficits, as assessed 7 to 8 days later. The impact of MDPV on striatal and hippocampal serotonergic assessments was minimal. Taken together, these data contribute to a growing pharmacological rubric for evaluating the ever-growing list of designer cathinone-related stimulants. The profile of MDPV compared with related psychostimulants is discussed. SIGNIFICANCE STATEMENT: Pharmacological characterization of the synthetic cathinone, 3,4-methylenedioxypyrovalerone (MDPV; commonly referred to as a "bath salt"), is critical for understanding the abuse liability and neurotoxic potential of this and related agents. Accordingly, the impact of MDPV on monoaminergic neurons is described and compared with that of related psychostimulants.
Topics: Animals; Benzodioxoles; Body Temperature; Central Nervous System Stimulants; Designer Drugs; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dopaminergic Neurons; Female; Male; Neostriatum; Pyrrolidines; Rats; Rats, Sprague-Dawley; Substance-Related Disorders; Vesicular Monoamine Transport Proteins; Synthetic Cathinone
PubMed: 32385092
DOI: 10.1124/jpet.119.264895 -
EvoDevo 2019Nicotinic and muscarinic acetylcholine receptors likely evolved in the cnidarian-bilaterian common ancestor. Both receptor families are best known for their role at...
BACKGROUND
Nicotinic and muscarinic acetylcholine receptors likely evolved in the cnidarian-bilaterian common ancestor. Both receptor families are best known for their role at chemical synapses in bilaterian animals, but they also have described roles as non-neuronal signaling receptors within the bilaterians. It is not clear when either of the functions for nicotinic or muscarinic receptors evolved. Previous studies in cnidarians suggest that acetylcholine's neuronal role existed prior to the cnidarian-bilaterian divergence, but did not address potential non-neuronal functions. To determine the origins of neuronal and non-neuronal functions of nicotinic acetylcholine receptors, we investigated the phylogenetic position of cnidarian acetylcholine receptors, characterized the spatiotemporal expression patterns of nicotinic receptors in , and compared pharmacological studies in to the previous work in other cnidarians.
RESULTS
Consistent with described activity in other cnidarians, treatment with acetylcholine-induced tentacular contractions in the cnidarian sea anemone Phylogenetic analysis suggests that the genome encodes 26 nicotinic (nAChRs) and no muscarinic (mAChRs) acetylcholine receptors and that nAChRs independently radiated in cnidarian and bilaterian linages. The namesake nAChR agonist, nicotine, induced tentacular contractions similar to those observed with acetylcholine, and the nAChR antagonist mecamylamine suppressed tentacular contractions induced by both acetylcholine and nicotine. This indicated that tentacle contractions are in fact mediated by nAChRs. Nicotine also induced the contraction of radial muscles, which contract as part of the peristaltic waves that propagate along the oral-aboral axis of the trunk. Radial contractions and peristaltic waves were suppressed by mecamylamine. The ability of nicotine to mimic acetylcholine responses, and of mecamylamine to suppress acetylcholine and nicotine-induced contractions, supports a neuronal function for acetylcholine in cnidarians. Examination of the spatiotemporal expression of nAChRs () during development and in juvenile polyps identified that are expressed in neurons, muscles, gonads, and large domains known to be consistent with a role in developmental patterning. These patterns are consistent with nAChRs functioning in both a neuronal and non-neuronal capacity in
CONCLUSION
Our data suggest that nAChR receptors functioned at chemical synapses in to regulate tentacle contraction. Similar responses to acetylcholine are well documented in cnidarians, suggesting that the neuronal function represents an ancestral role for nAChRs. Expression patterns of nAChRs are consistent with both neuronal and non-neuronal roles for acetylcholine in cnidarians. Together, these observations suggest that both neuronal and non-neuronal functions for the ancestral nAChRs were present in the cnidarian-bilaterian common ancestor. Thus, both roles described in bilaterian species likely arose at or near the base of nAChR evolution.
PubMed: 31700598
DOI: 10.1186/s13227-019-0136-3 -
Pharmacological Reports : PR Aug 2014The aim of the present study was to evaluate the involvement of the cholinergic receptors ligands in the memory-related responses in mice, using the novel object... (Comparative Study)
Comparative Study
BACKGROUND
The aim of the present study was to evaluate the involvement of the cholinergic receptors ligands in the memory-related responses in mice, using the novel object recognition (NOR) test.
METHODS
The NOR test is based on natural, exploratory abilities of animals exposed to a new environment. In the first session, two copies of the same object were presented. In the next sessions (30min and 24h after), one of the familiar object and a new object were presented.
RESULTS
The mice injected with nicotine (0.035 and 0.175mg/kg, free base, sc) before the first session spent more time exploring the new object than the familiar one at the second and third session, indicating that nicotine improved cognition. In turn, the mice injected with scopolamine (0.3 and 1mg/kg, ip) before the first session spent less time exploring the new object than the familiar one at the second and third trial, indicating that scopolamine impaired the memory performance. Additionally, the acute injection of drugs used in smoking cessation in humans: mecamylamine (0.5 and 1mg/kg) and bupropion (5 and 10mg/kg), prior to injections of nicotine (0.035mg/kg) or scopolamine (1mg/kg), significantly prevented nicotine-induced memory improvement or scopolamine-induced memory impairment, at the second and third session.
CONCLUSIONS
The results of our studies unveiling neuronal mechanisms for cholinergic system of memory processes, via both nicotinic and muscarinic cholinergic receptors, will be useful for development of more effective pharmacotherapies for memory impairment-like treatment of human disorders in which cholinergic pathways have been implicated.
Topics: Analysis of Variance; Animals; Bupropion; Cholinergic Agents; Dose-Response Relationship, Drug; Exploratory Behavior; Male; Mecamylamine; Memory; Mice; Nicotine; Pattern Recognition, Visual; Scopolamine
PubMed: 24948066
DOI: 10.1016/j.pharep.2014.02.002 -
Pharmacology, Biochemistry, and Behavior Jul 2021Electronic-cigarette's (ECIGs) popularity has grown over the last decade and changed the way individuals administer nicotine. Preclinical research is imperative for...
Electronic-cigarette's (ECIGs) popularity has grown over the last decade and changed the way individuals administer nicotine. Preclinical research is imperative for understanding the addictive properties and health-risks associated with ECIG use; however, there is not a standard dosing regimen used across research laboratories. The main objective was to determine how vapor puff durations, administration session length, and flavored e-liquid alter general and mood-disorder related behaviors while providing a foundation of vapor administration parameters. Adult male and female C57BL/6 mice were exposed to several nicotine-free unflavored vapor puff durations (1, 3, 6, or 10 s) and vapor administration session lengths (10 and 30 min) then measured on the following assays: locomotor activity (LMA), tail suspension test (TST), and light-dark test. The effects of mecamylamine and the time-course of vapor-induced depression of LMA also were assessed. Additionally, mice were exposed to flavored (strawberry and adventurers tobacco blend) vapor inhalation and measured on locomotor activity, tail suspension test, and light-dark test. Following both 10 and 30 min vapor administration session, there was a puff duration-dependent decrease in distance traveled, time in center, and rearing. The vapor-induced depression of LMA was not mediated by nicotine or nicotinic acetylcholine receptor (nAChR) activation and lasted 60-90 min. The 10 s puff duration produced an anxiogenic-like effect in the light-dark test by decreasing the time spent in the light side. Vapor inhalation did not significantly alter TST behavior. No significant effects of sex or flavor were found. The anxiogenic-like effects of nicotine-free vapor inhalation are concerning as many adolescents vape nicotine-free flavored e-liquid, and there is an association between ECIGs and mood disorders. Additionally, these studies demonstrate that vapor puff duration, but not vapor administration session length, is an important variable to consider during research design as it can become a confounding variable and alter baseline behaviors.
Topics: Administration, Inhalation; Adolescent; Animals; Anxiety; Behavior, Animal; E-Cigarette Vapor; Electronic Nicotine Delivery Systems; Female; Flavoring Agents; Humans; Locomotion; Male; Mecamylamine; Mice; Mice, Inbred C57BL; Nicotine; Nicotinic Antagonists; Receptors, Nicotinic; Sex Factors; Time Factors; Vaping
PubMed: 34019915
DOI: 10.1016/j.pbb.2021.173207 -
Frontiers in Molecular Biosciences 2021The cholinergic anti-inflammatory pathway plays an important role in controlling inflammation. This study investigated the effects of varenicline, an α7 nicotinic...
The cholinergic anti-inflammatory pathway plays an important role in controlling inflammation. This study investigated the effects of varenicline, an α7 nicotinic acetylcholine receptor (α7nAChR) agonist, on inflammatory cytokine levels, cell proliferation, and migration rates in a lipopolysaccharide (LPS)-induced inflammation model in RAW 264.7 murine macrophage cell lines. The cells were treated with increasing concentrations of varenicline, followed by LPS incubation for 24 h. Prior to receptor-mediated events, anti-inflammatory effects of varenicline on different cytokines and chemokines were investigated using a cytokine array. Nicotinic AChR-mediated effects of varenicline were investigated by using a non-selective nAChR antagonist mecamylamine hydrochloride and a selective α7nAChR antagonist methyllycaconitine citrate. TNFα, IL-1β, and IL-6 levels were determined by the ELISA test in cell media 24 h after LPS administration and compared with those of dexamethasone. The rates of cellular proliferation and migration were monitored for 24 h after drug treatment using a real-time cell analysis system. Varenicline decreased LPS-induced cytokines and chemokines including TNFα, IL-6, and IL-1β via α7nAChRs to a similar level that observed with dexamethasone. Varenicline treatment decreased LPS-induced cell proliferation, without any nAChR involvement. On the other hand, the LPS-induced cell migration rate decreased with varenicline via α7nAChR. Our data suggest that varenicline inhibits LPS-induced inflammatory response by activating α7nAChRs within the cholinergic anti-inflammatory pathway, reducing the cytokine levels and cell migration.
PubMed: 34712695
DOI: 10.3389/fmolb.2021.721533 -
In Vivo (Athens, Greece) 2020Cigarette smoke (CS) is a major environmental health threat. The oxidative stress induced by CS on keratinocytes and the possible protective effect of nicotine, its...
BACKGROUND/AIM
Cigarette smoke (CS) is a major environmental health threat. The oxidative stress induced by CS on keratinocytes and the possible protective effect of nicotine, its receptor inhibitors, and Pinus halepensis bark extract in relation to known antioxidants were investigated.
MATERIALS AND METHODS
Primary mouse keratinocytes were exposed to cigarette smoke in the presence and absence of Pinus halepensis bark extract (1 μg/ml), rutin (50 μM) and ascorbic acid (250 μM), nicotine (1 μM) with or without mecamylamine (5 μM) and α-bungarotoxin (0.1 μM). Keratinocyte viability and oxidative stress were evaluated by MTT and fluorescence assays.
RESULTS
Pinus halepensis bark extract decreased the oxidative stress and increased the viability of keratinocytes, and moreover, these effects were more pronounced compared to the mixture of rutin and L-ascorbic acid. Nicotine significantly enhanced the viability potentiation of the beneficial effect induced by Pinus halepensis bark extract. Mecamylamine and α-bungarotoxin showed no specific effect.
CONCLUSION
Pinus halepensis bark extract in combination with nicotine may successfully reverse skin damage induced by cigarette smoke.
Topics: Animals; Keratinocytes; Mice; Nicotine; Oxidative Stress; Pinus; Plant Bark; Plant Extracts; Smoking
PubMed: 32606153
DOI: 10.21873/invivo.11978 -
British Journal of Pharmacology Dec 2014Previous studies have demonstrated that nicotine releases protons from adrenergic nerves via stimulation of nicotinic ACh receptors and activates transient receptor...
BACKGROUND AND PURPOSE
Previous studies have demonstrated that nicotine releases protons from adrenergic nerves via stimulation of nicotinic ACh receptors and activates transient receptor potential vanilloid-1 (TRPV1) receptors located on calcitonin gene-related peptide (CGRP)-containing (CGRPergic) vasodilator nerves, resulting in vasodilatation. The present study investigated whether perivascular nerves release protons, which modulate axon-axonal neurotransmission.
EXPERIMENT APPROACH
Perfusion pressure and pH levels of perfusate in rat-perfused mesenteric vascular beds without endothelium were measured with a pressure transducer and a pH meter respectively.
KEY RESULTS
Periarterial nerve stimulation (PNS) initially induced vasoconstriction, which was followed by long-lasting vasodilatation and decreased pH levels in the perfusate. Cold-storage denervation of the preparation abolished the decreased pH and vascular responses to PNS. The adrenergic neuron blocker guanethidine inhibited PNS-induced vasoconstriction and effects on pH, but not PNS-induced vasodilatation. Capsaicin (CGRP depletor), capsazepine and ruthenium red (TRPV1 inhibitors) attenuated the PNS-induced decrease in pH and vasodilatation. In denuded preparations, ACh caused long-lasting vasodilatation and lowered pH; these effects were inhibited by capsaicin pretreatment and atropine, but not by guanethidine or mecamylamine. Capsaicin injection induced vasodilatation and a reduction in pH, which were abolished by ruthenium red. The use of a fluorescent pH indicator demonstrated that application of nicotine, ACh and capsaicin outside small mesenteric arteries reduced perivascular pH levels and these effects were abolished in a Ca(2+) -free medium.
CONCLUSION AND IMPLICATION
These results suggest that protons are released from perivascular adrenergic and CGRPergic nerves upon PNS and these protons modulate transmission in CGRPergic nerves.
Topics: Acetylcholine; Adrenergic Neurons; Animals; Atropine; Axons; Calcitonin Gene-Related Peptide; Capsaicin; Cholinergic Agonists; Guanethidine; Hydrogen-Ion Concentration; Mecamylamine; Mesenteric Arteries; Muscarinic Antagonists; Nicotinic Antagonists; Protons; Rats; Ruthenium Red; Sympatholytics; Synaptic Transmission; Vasoconstriction; Vasodilation
PubMed: 25117291
DOI: 10.1111/bph.12878