Identification of an m6A Natural Inhibitor, Lobeline, That Reverses Lenvatinib Resistance in Hepatocellular Tumors.

Hepatocellular carcinoma (HCC) is an aggressive cancer that has an effect on human health. As a first-line drug for HCC, despite its excellent efficacy, lenvatinib (Len) is prone to developing drug resistance in HCC patients. The N6-methyladenosine (m6A) modification is not only related to the development of HCC but also shows great potential in overcoming HCC resistance. Using Dot Blot, our group first screened a small molecule m6A regulator, lobeline (Lob), from a library of 390 compounds (mostly natural products). In vitro experiments demonstrated that Lob could significantly enhance the sensitivity to Len of Len-resistant HCC (HCC/Len) and inhibit migration of resistant cells. In Len-resistant cell-derived and patient-derived xenograft models, Lob could reverse the resistant phenotype, with reductions in tumor volume of 68% and 60%, respectively. Furthermore, MeRIP-m6A sequencing results indicated that the underlying molecular mechanism of Lob reversal of HCC drug resistance was related to UBE3B. Taken together, this study highlighted that Lob, a plant derived natural product, could reverse the resistance of HCC to Len by regulating the m6A levels. It is hoped that this will provide a pharmacological research basis for the clinical treatment of HCC patients.

Multispectroscopic and Theoretical Investigation on the Binding Interaction of a Neurodegenerative Drug, Lobeline with Human Serum Albumin: Perturbation in Protein Conformation and Hydrophobic-Hydrophilic Surface.

Lobeline (LOB), a naturally occurring alkaloid, has a broad spectrum of pharmacological activities and therapeutic potential, including applications in central nervous system disorders, drug misuse, multidrug resistance, smoking cessation, depression, and epilepsy. LOB represents a promising compound for developing treatments in various medical fields. However, despite extensive pharmacological profiling, the biophysical interaction between the LOB and proteins remains largely unexplored. In the current article, a range of complementary photophysical and cheminformatics methodologies were applied to study the interaction mechanism between LOB and the carrier protein HSA. Steady-state fluorescence and fluorescence lifetime experiments confirmed the static-quenching mechanisms in the HSA-LOB system. "K" (binding constant) of the HSA-LOB system was determined to be 105 M-1, with a single preferable binding site in HSA. The forces governing the HSA-LOB stable complex were analyzed by thermodynamic parameters and electrostatic contribution. The research also investigated how various metal ions affect complex binding. Site-specific binding studies depict Site I as probable binding in HSA by LOB. We conducted synchronous fluorescence, 3D fluorescence, and circular dichroism studies to explore the structural alteration occurring in the microenvironment of amino acids. To understand the robustness of the HSA-LOB complex, we used theoretical approaches, including molecular docking and MD simulations, and analyzed the principal component analysis and free energy landscape. These comprehensive studies of the structural features of biomolecules in ligand binding are of paramount importance for designing targeted drugs and delivery systems.

Lobeline: A multifunctional alkaloid modulates cholinergic and glutamatergic activities.

Developing drugs for Alzheimer's disease (AD) is an extremely challenging task due to its devastating pathology. Previous studies have indicated that natural compounds play a crucial role as lead molecules in the development of drugs. Even though, there are remarkable technological advancements in the isolation and synthesis of natural compounds, the targets for many of them are still unknown. In the present study, lobeline, a piperidine alkaloid has been identified as a cholinesterase inhibitor through chemical similarity assisted target fishing method. The structural similarities between lobeline and donepezil, a known acetylcholinesterase (AChE) inhibitor encouraged us to hypothesize that lobeline may also exhibit AChE inhibitory properties. It was further confirmed by in silico, in vitro and biophysical studies that lobeline could inhibit cholinesterase. The binding profiles indicated that lobeline has a higher affinity for AChE than BChE. Since excitotoxicity is one of the major pathological events associated with AD progression, we also investigated the neuroprotective potential of lobeline against glutamate mediated excitotoxicity in rat primary cortical neurons. The cell based NMDA receptor (NMDAR) assay with lobeline suggested that neuroprotective potential of lobeline is mediated through the blockade of NMDAR activity.

Quick nic: novel smokeless nicotine products and pediatric trends.

PURPOSE OF REVIEW: The development and marketing of smokeless nicotine products in recent years have become increasingly popular among adolescents. In addition to well known conventional inhaled nicotine products, noninhaled products, such as nicotine toothpicks, orbs, lozenges, strips, and more, have dangerously captivated a new youth audience. Although smokeless nicotine products may seem to be less threatening than conventional inhaled nicotine products, there are significant risks associated with the use of these products, including addiction and severe health issues. The purpose of this review is to provide up-to-date information about alternative nicotine products currently on the market that may appeal to youth, and the dangers of nicotine use for pediatric populations. RECENT FINDINGS: Smokeless nicotine products appeal to minors with their varying flavors and discrete packaging. These products may lead to nicotine toxicity as well as severe health problems, such as cancer, issues with reproduction, and heart attacks. Nicotine is extremely dangerous for young children; in fact, using nicotine products before the age of 18 years can lead to addiction and is linked to an increased likelihood of experimenting with stronger nicotine products or illicit drugs. The development of inconspicuous nicotine packaging has led to increasing concerns for accidental nicotine exposure and overdose in youth. SUMMARY: Greater knowledge regarding current nicotine products on the market, specifically smokeless nicotine products, will help clinicians be more aware of the dangers associated with these products. Clinicians will be better able to provide their patients and families with proper guidance to avoid nicotine addiction, further drug use, and detrimental health issues. Caregivers and medical professionals must recognize novel and inconspicuous nicotine products commonly used among youth, understand the signs of nicotine abuse and dependence, and take measures to address possible nicotine-related health risks.

2,6-Disubstituted Piperidine Alkaloids with Neuroprotective Activity from Hippobroma longiflora.

Three new alkaloids, hipporidine A (1: ), hipporidine B (2: ), and (-)-lobeline N-oxide (3: ), were discovered from the whole plant of Hippobroma longiflora together with five known compounds (4: -8: ). Their 2,6-disubstituted piperidine structures were established based on the HRESIMS, NMR (COSY, HMBC, HSQC, NOESY), and UV spectroscopic data. Hipporidines A (1: ) and B (2: ) possess a rare 1,3-oxazinane moiety. Compound 3: is the N-oxide derivative of (-)-lobeline (6: ). Moreover, the absolute configuration of norlobeline (5: ) was established by single-crystal X-ray diffraction analysis. Three major secondary metabolites (6: -8: ) were evaluated for their neuroprotective effect against paclitaxel-induced neurotoxicity. Consequently, pretreatment with compound 8: at a concentration of 1.0 µM displayed significant attenuation on paclitaxel-damaged neurite outgrowth of dorsal root ganglion neurons without interfering with the cytotoxicity of paclitaxel on cervical cancer SiHa cells.

Overall and cause-specific mortality rates among men and women with high exposure to indoor air pollution from the use of smoky and smokeless coal: a cohort study in Xuanwei, China.

OBJECTIVES: Never-smoking women in Xuanwei (XW), China, have some of the highest lung cancer rates in the country. This has been attributed to the combustion of smoky coal used for indoor cooking and heating. The aim of this study was to evaluate the spectrum of cause-specific mortality in this unique population, including among those who use smokeless coal, considered 'cleaner' coal in XW, as this has not been well-characterised. DESIGN: Cohort study. SETTING: XW, a rural region of China where residents routinely burn coal for indoor cooking and heating. PARTICIPANTS: Age-adjusted, cause-specific mortality rates between 1976 and 2011 were calculated and compared among lifetime smoky and smokeless coal users in a cohort of 42 420 men and women from XW. Mortality rates for XW women were compared with those for a cohort of predominately never-smoking women in Shanghai. RESULTS: Mortality in smoky coal users was driven by cancer (41%), with lung cancer accounting for 88% of cancer deaths. In contrast, cardiovascular disease (CVD) accounted for 32% of deaths among smokeless coal users, with 7% of deaths from cancer. Total cancer mortality was four times higher among smoky coal users relative to smokeless coal users, particularly for lung cancer (standardised rate ratio (SRR)=17.6). Smokeless coal users had higher mortality rates of CVD (SRR=2.9) and pneumonia (SRR=2.5) compared with smoky coal users. These patterns were similar in men and women, even though XW women rarely smoked cigarettes. Women in XW, regardless of coal type used, had over a threefold higher rate of overall mortality, and most cause-specific outcomes were elevated compared with women in Shanghai. CONCLUSIONS: Cause-specific mortality burden differs in XW based on the lifetime use of different coal types. These observations provide evidence that eliminating all coal use for indoor cooking and heating is an important next step in improving public health particularly in developing countries.

From cis-Lobeline to trans-Lobeline: Study on the Pharmacodynamics and Isomerization Factors.

Lobeline is an alkaloid derived from the leaves of an Indian tobacco plant (Lobelia inflata), which has been prepared by chemical synthesis. It is classified as a partial nicotinic agonist and has a long history of therapeutic usage ranging from emetic and respiratory stimulant to tobacco smoking cessation agent. The presence of both cis and trans isomers in lobeline is well known, and many studies on the relationship between the structure and pharmacological activity of lobeline and its analogs have been reported. However, it is a remarkable fact that no studies have reported the differences in pharmacological activities between the two isomers. In this article, we found that different degrees of isomerization of lobeline injection have significant differences in respiratory excitatory effects in pentobarbital sodium anesthetized rats. Compared with cis-lobeline injections, the respiratory excitatory effect was significantly reduced by 50.2% after administration of injections which contained 36.9% trans-lobeline. The study on the influencing factors of isomerization between two isomers shown that this isomerization was a one-way isomerism and only converted from cis to trans, where temperature was the catalytic factor and pH was the key factor. This study reports a new discovery. Despite the widespread use of ventilators, first-aid medicines such as nikethamide and lobeline has retired to second line, but as a nonselective antagonist with high affinity for a4b2 and a3b2 nicotinic acetylcholine receptors (nAChRs). In recent years, lobeline has shown great promise as a therapeutic drug for mental addiction and nervous system disorders, such as depression, Alzheimer disease and Parkinson disease. Therefore, we suggest that the differences between two isomers should be concerned in subsequent research papers and applications.

[Acupuncture combined with smokeless or smoky moxibustion for regulating immune function of experimental chronic rhinosinusitis mice].

OBJECTIVE: To observe the therapeutic effect of moxa fume in the treatment of chronic rhinosinusitis（CRS） and the effect of acupuncture plus smokeless moxibustion or smoky moxibustion on the expression of thymic stromal lymphopoietin (TSLP) and pituitary adenylate cyclase activating polypeptide (PACAP) proteins in the sinus mucosal tissue in CRS mice. METHODS: Sixty male C57BL/6J mice were randomly divided into 6 groups, namely normal control, sham operation, CRS model, medication, acupuncture plus smokeless moxibustion (Acu+smokeless Moxi) and acupuncture plus smoky moxibustion (Acu+smoky Moxi) groups, with 20 mice in each group. The CRS model was established by inserting a piece of polyporous sponge filled with streptococcus pneumoniae into the maxillary sinus after operation. The mice in the sham operation group received skin incision after opening the maxillary sinus. Mice of the medication group received gavage of clarithromycin 0.103 g·kg-1·d-1 for 21 days. For mice of the Acu+smokeless Moxi and Acu +smoky Moxi groups, manual acupuncture stimulation was applied to bilateral "Zusanli" (ST36), "Shenshu" (BL23) and "Hegu" (LI4) with the needles retained for 30 min, once every other day, and on the following day, moxibustion was applied to "Guanyuan" (CV4) and "Shenque" (BL23) for 20 min, once every other day. The treatment was given for 21 days. Mice of the normal, sham operation and model groups received gavage of normal saline (200 µL/d) for 21 days. Histopathological changes of the nasal mucosa were observed after H.E. staining, the TSLP and PACAP contents and expression were determined by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, separately. RESULTS: At the end of the treatment, mice of the model group still had symptoms of nasal obstruction and runny nose, but those of the 3 treatment groups were obviously relieved in the nasal symptoms. H.E. staining showed an obvious chronic inflammatory reaction in the sinus mucosa, uneven distribution of the mucosal epithelium and necrotic and exfoliated epithelial cells, hyperplasia of fibrous tissue in the submucosa, etc. in the model group, which were relatively milder in the medication, Acu+smokeless Moxi and Acu+smoky Moxi groups, while no obvious inflammation was found in the normal group and sham operation group. In comparison with the normal group, no significant changes were found in the expression levels of PACAP and TSLP in the sham operation group (P>0.05). The expression level of PACAP was significantly lower (P<0.05) and that of TSLP significantly higher in the model group than in the normal and sham operatin groups (P<0.05). Compared with the model group, no significant changes were found in the expression of PACAP in the medication, Acu+smokeless Moxi and Acu+smoky Moxi groups (P>0.05), and the expression of TSLP was further obviously increased in the Acu+smokeless Moxi group (P<0.01), but obviously decreased in the Acu+smoky Moxi group (P<0.01). CONCLUSION: Acupuncture combined with smoky moxibustion can down-regulate the expression of TSLP protein in the nasal sinus mucosa in CRS mice, which maybe contribute to its effect in reducing the inflammatory reaction and nasal symptoms.

Chemical Profiling of Lobelia chinensis with High-Performance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry (HPLC/Q-TOF MS) Reveals Absence of Lobeline in the Herb.

Lobelia chinensis is a kind of herbal medicine widely distributed and used in Asia. The chemical components of this herb, however, have not been well studied until now. Lobeline, as an essential and famous bioactive compound in Lobelia genus, has been assumed to be present in L. chinensis. In order to ascertain its presence and, more importantly, proper use of this herb, chemical profiling this herb with highly sensitive and high-resolution analytical mass spectrometry was applied. In this study, high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF MS) method was employed to systematically profile the chemical constituents of L. chinensis for the first time. Comparative chemical profiling study of L. chinensis and Lobelia inflata was also conducted to provide evidence whether lobeline is present or not. Piperidine alkaloids except for lobeline, alkaloid-lignan hybrids, flavonoids, polyacetylenes, nonanedioic acid, and some new phytochemicals were successfully identified in L. chinensis simultaneously. Comparing to the chemical profiles of L. inflata, lobeline was found to be absent in L. chinensis. All of the secondary metabolites in L. chinensis were determined with the HPLC/Q-TOF MS method. The absence of lobeline in L. chinensis was confirmed after this extensive study.

New Scaffold for Lead Compounds to Treat Methamphetamine Use Disorders.

Despite increased methamphetamine use worldwide, pharmacotherapies are not available to treat methamphetamine use disorder. The vesicular monoamine transporter-2 (VMAT2) is an important pharmacological target for discovery of treatments for methamphetamine use disorder. VMAT2 inhibition by the natural product, lobeline, reduced methamphetamine-evoked dopamine release, methamphetamine-induced hyperlocomotion, and methamphetamine self-administration in rats. Compared to lobeline, lobelane exhibited improved affinity and selectivity for VMAT2 over nicotinic acetylcholine receptors. Lobelane inhibited neurochemical and behavioral effects of methamphetamine, but tolerance developed to its behavioral efficacy in reducing methamphetamine self-administration, preventing further development. The lobelane analog, R-N-(1,2-dihydroxypropyl)-2,6-cis-di-(4-methoxyphenethyl)piperidine hydrochloride (GZ-793A), potently and selectively inhibited VMAT2 function and reduced neurochemical and behavioral effects of methamphetamine. However, GZ-793A exhibited potential to induce ventricular arrhythmias interacting with human-ether-a-go-go (hERG) channels. Herein, a new lead, R-3-(4-methoxyphenyl)-N-(1-phenylpropan-2-yl)propan-1-amine (GZ-11610), from the novel scaffold (N-alkyl(1-methyl-2-phenylethyl)amine) was evaluated as a VMAT2 inhibitor and potential therapeutic for methamphetamine use disorder. GZ-11610 was 290-fold selective for VMAT2 over dopamine transporters, suggesting that it may lack abuse liability. GZ-11610 was 640- to 3500-fold selective for VMAT2 over serotonin transporters and nicotinic acetylcholine receptors. GZ-11610 exhibited > 1000-fold selectivity for VMAT2 over hERG, representing a robust improvement relative to our previous VMAT2 inhibitors. GZ-11610 (3-30 mg/kg, s.c. or 56-300 mg/kg, oral) reduced methamphetamine-induced hyperactivity in methamphetamine-sensitized rats. Thus, GZ-11610 is a potent and selective inhibitor of VMAT2, may have low abuse liability and low cardiotoxicity, and after oral administration is effective and specific in inhibiting the locomotor stimulant effects of methamphetamine, suggesting further investigation as a potential therapeutic for methamphetamine use disorder.

Levels of salivary thiocyanate and its relation with occurrence of micronuclei using exfoliative cytology in smokers and nonsmokers.

AIMS: To evaluate the levels of salivary thiocyanate and its relation with the occurrence of micronuclei (MN) using exfoliative cytology in smokers and nonsmokers. MATERIALS AND METHODS: One hundred and twenty patients were divided into 3 groups: nonsmoker group 1 (control), smokers group 2, and smokers group 3. Their saliva was collected and analyzed for thiocyanate levels, and exfoliative cytology was evaluated for the presence of MN. STATISTICAL ANALYSIS USED: Fisher's exact test and ANOVA test were used. RESULTS: It was seen that as the grade of smoking increased, the levels of salivary thiocyanate and occurrence of MN increased. CONCLUSIONS: Detection and quantification of "biomarkers" such as salivary thiocyanate and MN in noninvasive and painless procedures such as oral exfoliative cytology can be an upcoming research domain in the field of cancer prevention and therapeutics.

Alternative pharmacological strategies for adult ADHD treatment: a systematic review.

Adult Attention Deficit Hyperactivity Disorder (ADHD) is a prevalent psychiatric condition associated with high disability and frequent comorbidity. Current standard pharmacotherapy (methylphenidate and atomoxetine) improves ADHD symptoms in the short-term, but poor data were published about long-term treatment. In addition a number of patients present partial or no response to methylphenidate and atomoxetine. Research into the main database sources has been conducted to obtain an overview of alternative pharmacological approaches in adult ADHD patients. Among alternative compounds, amphetamines (mixed amphetamine salts and lisdexamfetamine) have the most robust evidence of efficacy, but they may be associated with serious side effects (e.g. psychotic symptoms or hypertension). Antidepressants, particularly those acting as noradrenaline or dopamine enhancers, have evidence of efficacy, but they should be avoided in patients with comorbid bipolar disorder. Finally metadoxine and lithium may be particularly suitable in case of comorbid alcohol misuse or bipolar disorder.

Lobeline improves acute lung injury via nuclear factor-κB-signaling pathway and oxidative stress.

Acute lung injury (ALI) is a severe, life-threatening medical condition whose pathogenesis is linked to neutrophil infiltration of the lung. Activation and recruitment of neutrophils to the lung is mostly attributed to the production of chemokines NO, IL-6, for instance. This study aims to investigate lobeline ability in reducing NO production, and nitric oxide synthase (iNOs) expression. Lobeline was tested by inhibiting phosphorylation of mitogen-activated protein kinases (MAPKs), NF-κB and IκBα in LPS-stimulated RAW 264.7 cells. When RAW 264.7 macrophages were given lobeline with LPS, a significant concentration-dependent inhibition of NO production was detected. In vivo tests, mice were either treated with normal saline, 10mg/kg dexmethasone or 5, 10, 20mg/kg lobeline intraperitoneally, and after an hour, the administration of 5mg/kg of LPS was given intratracheally. External performance, cytokines, MAPK pathways and antioxidative enzymes (AOEs) were also carried out to evaluate the effects of these drugs. This is the first investigation in which lobeline was found to effectively inhibit acute lung edema, which may provide a potential target for treating ALI. Lobeline may utilize MAPKs pathways as well as AOEs activity to attenuate LPS-induced nonspecific pulmonary inflammation.

Effects of lobeline and reboxetine, fluoxetine, or bupropion combination on depression-like behaviors in mice.

Evidence suggests that lobeline, a nicotinic acetylcholine receptor ligand, has antidepressant-like properties in mice. The present study investigated the possible additive or synergistic effects of lobeline in combination with commonly used antidepressants, such as reboxetine, fluoxetine, or bupropion, using the tail suspension test (TST) and the forced swim test (FST) in C57BL/6J mice. Reboxetine (5 or 10 mg/kg, i.p.), fluoxetine (5 or 10 mg/kg, i.p.), or bupropion (2 or 4 mg/kg, i.p.) were administered 30 min before TST or FST. A fixed dose of lobeline (1 mg/kg, i.p.) was injected 15 min prior to tests. Co-administration of lobeline and reboxetine, fluoxetine, or bupropion significantly reduced immobility time in the TST and FST in comparison to the antidepressants used alone. The results suggest that lobeline enhanced the effects of reboxetine, fluoxetine, or bupropion in mice. Therefore, lobeline or similar nicotinic receptor ligand may have therapeutic potential as an adjunct for the treatment of major depression.

HPLC-ESI-MS/MS of brain neurotransmitter modulator lobeline and related piperidine alkaloids in Lobelia inflata L.

There is a renewed interest in lobelia alkaloids because of their activity on the central nervous system. Lobeline, the most active of them, a nicotinic receptor ligand and neurotransmitter transporter inhibitor, is a candidate pharmacotherapy for metamphetamine abuse. In the present work, high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry in positive ion mode was used for investigating the alkaloid profile in Lobelia inflata L. Chromatographic separations were achieved on a Gemini C6-phenyl reversed-phase column providing good peak shape and improved selectivity. Being mostly 2,6-disubstituted piperidines, lobelia alkaloids presented abundant [M + H](+) ions with typical fragmentation. Identification was possible from a few specific ions, especially those resulting from excision of one of the substituents. Based on fragmentation pattern of lobeline as reference compound, 52 alkaloids were identified in the aqueous methanolic extract of L. inflata in contrast to the previously known some 20. Structural variability of these alkaloids identified arises basically from their substituents which can be phenyl-2-ketoethyl- or phenyl-2-hydroxyethyl units as well as their methyl-, ethyl- or propyl- homologues attached in different combinations. Several propyl homologue lobelia alkaloids and five hydroxypiperidine derivatives were found in the plant at the first time. In addition to 8-O-esters of 2-monosubstituted piperidine alkaloids previously reported by us in L. inflata, a 3-hydroxy-3-phenylpropanoic acid ester of hydroxyallosedamine ring-substituted was also identified as a new natural product. High-performance liquid chromatography-electrospray ionization tandem mass spectrometry can be successfully applied to Lobeliacae plant samples in the routine screening for new and known bioactive constituents, quality control of the crude drug, lobelia herba, alkaloid production studies, breeding and chemotaxonomy.

Pharmacological chaperones increase residual ß-galactocerebrosidase activity in fibroblasts from Krabbe patients.

Krabbe disease or globoid cell leukodystrophy is a degenerative, lysosomal storage disease resulting from the deficiency of ß-galactocerebrosidase activity. This enzyme catalyzes the lysosomal hydrolysis of galactocerebroside and psychosine. Krabbe disease is inherited as an autosomal recessive trait, and many of the 70 disease-causing mutations identified in the GALC gene are associated with protein misfolding. Recent studies have shown that enzyme inhibitors can sometimes translocate misfolded polypeptides to their appropriate target organelle bypassing the normal cellular quality control machinery and resulting in enhanced activity. In search for pharmacological chaperones that could rescue the ß-galactocerebrosidase activity, we investigated the effect of α-Lobeline or 3',4',7-trihydroxyisoflavone on several patient-derived fibroblast cell lines carrying missense mutations, rather than on transduced cell lines. Incubation of these cell lines with α-lobeline or 3',4',7-trihydroxyisoflavone leads to an increase of ß-galacocerebrosidase activity in p.G553R + p.G553R, in p.E130K + p.N295T and in p.G57S + p.G57S mutant forms over the critical threshold. The low but sustained expression of ß-galactocerebrosidase induced by these compounds is a promising result; in fact, it is known that residual enzyme activity of only 15-20% is sufficient for clinical efficacy. The molecular interaction of the two chaperones with ß-galactocerebrosidase is also supported by in silico analysis. Collectively, our combined in silico-in vitro approach indicate α-lobeline and 3',4',7-trihydroxyisoflavone as two potential pharmacological chaperones for the treatment or improvement of quality of life in selected Krabbe disease patients.

The effects of lobeline on nicotine withdrawal-induced depression-like behavior in mice.

RATIONALE: Evidence suggests that neuronal nicotinic acetylcholine receptor (nAChR) ligand lobeline has antidepressant-like properties. OBJECTIVES: The present study investigated the effects of lobeline on nicotine withdrawal-induced depression-like behavior. METHODS: Adult C57BL/6J mice were exposed to nicotine (200 µg/ml) in drinking solution for 3 weeks. During withdrawal, depression-like behavior was measured by the forced swim test (FST). We also determined norepinephrine (NE) levels in the prefrontal cortex (PFC) and hippocampus during nicotine withdrawal. Furthermore, we determined the effects of repeated treatment with lobeline or a selective α4ß2 nAChR ligand 3-(pyridine-3́-yl)-cytisine on brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP-responsive element binding (p-CREB) protein expression in the hippocampus. RESULTS: Withdrawal from chronic nicotine increased immobility time in the FST, a measure for depression-like behavior. Pretreatment with lobeline significantly decreased immobility time during nicotine withdrawal. In addition, pretreatment with lobeline attenuated nicotine withdrawal-induced increased NE levels in the PFC and hippocampus. Further, repeated treatment with lobeline or 3-(pyridine-3́-yl)-cytisine decreased immobility time in the FST and reduced withdrawal-induced increased BDNF and p-CREB expression in the hippocampus. CONCLUSIONS: Taken together, our results indicate that lobeline attenuated nicotine withdrawal-induced depression-like behavior likely by targeting brain nAChRs, noradrenergic neurotransmission, and/or hippocampal BDNF. Thus, lobeline may have some potential to prevent smoking relapse by counteracting nicotine withdrawal-induced depression in humans.

Piperidine, pyridine alkaloid inhibition of fetal movement in a day 40 pregnant goat model.

Inhibition of fetal movement is one mechanism behind the development of multiple congenital contracture-type defects in developing fetuses of humans and animals. We tested the alkaloids anabasine, lobeline, and myosmine for agonist actions, and sensitivity to alpha conotoxins EI and GI blockade at fetal muscle-type nicotinic acetylcholine receptors (nAChR) expressed by TE-671 cells. We also determined if the alkaloids decreased fetal movement in an IV dosed, day 40 pregnant goat model. In TE-671 cells, all three alkaloids elicited concentration-dependent changes in membrane potential sensing dye fluorescence. 1.0 µM alpha conotoxin GI shifted the concentration-effect curves of anabasine and myosmine to the right, and decreased maximal responses. Neither of the conotoxins blocked the actions of lobeline in TE-671 cells. In the day 40 pregnant goats, 0.8 mg/kg anabasine abolished fetal movement at 30 and 60 min after dosing and fetal movement was reduced by lobeline and myosmine. The blockade of anabasine and myosmine actions in TE-671 cells by alpha conotoxin GI indicates that they are agonists at fetal muscle-type nAChR. All three alkaloids did significantly decrease fetal movement in the day 40 pregnant goat model suggesting a potential for these alkaloids to cause multiple congenital contracture-type defects in developing fetuses.