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British Journal of Pharmacology Dec 2020Mucociliary clearance is an innate immune process of the airways, essential for removal of respiratory pathogens. It depends on ciliary beat and ion and fluid...
BACKGROUND AND PURPOSE
Mucociliary clearance is an innate immune process of the airways, essential for removal of respiratory pathogens. It depends on ciliary beat and ion and fluid homeostasis of the epithelium. We have shown that nicotinic ACh receptors (nAChRs) activate ion transport in mouse tracheal epithelium. Yet the receptor subtypes and signalling pathways involved remained unknown.
EXPERIMENTAL APPROACH
Transepithelial short circuit currents (I ) of freshly isolated mouse tracheae were recorded using the Ussing chamber technique. Changes in [Ca ] were studied on freshly dissociated mouse tracheal epithelial cells.
KEY RESULTS
Apical application of the nAChR agonist nicotine transiently increased I . The nicotine effect was abolished by the nAChR antagonist mecamylamine. α-Bungarotoxin (α7 antagonist) had no effect. The agonists epibatidine (α3β2, α4β2, α4β4 and α3β4) and A-85380 (α4β2 and α3β4) increased I . The antagonists dihydro-β-erythroidine (α4β2, α3β2, α4β4 and α3β4), α-conotoxin MII (α3β2) and α-conotoxin PnIA (α3β2) reduced the nicotine effect. Nicotine- and epibatidine-induced currents were unaltered in β2 mice, but in β4 mice no increase was observed. In the presence of thapsigargin (endoplasmatic reticulum Ca -ATPase inhibitor) or the ryanodine receptor antagonists JTV-519 and dantrolene there was a reduction in the nicotine-effect, indicating involvement of Ca release from intracellular stores. Additionally, the PKA inhibitor H-89 and the TMEM16A (Ca -activated chloride channel) inhibitor T16Ainh-A01 significantly reduced the nicotine-effect.
CONCLUSION AND IMPLICATIONS
α3β4 nAChRs are responsible for the nicotine-induced current changes via Ca release from intracellular stores, PKA and ryanodine receptor activation. These nAChRs might be possible targets to stimulate chloride transport via TMEM16A.
Topics: Acetylcholine; Animals; Dihydro-beta-Erythroidine; Mecamylamine; Mice; Nicotine; Nicotinic Agonists; Nicotinic Antagonists; Receptors, Nicotinic
PubMed: 32959891
DOI: 10.1111/bph.15270 -
Medicina (Kaunas, Lithuania) Jan 2023: This study aimed to identify the analgesic properties of immature extract (iROE) using a postoperative-pain rat model. We also aimed to compare the analgesic effects...
: This study aimed to identify the analgesic properties of immature extract (iROE) using a postoperative-pain rat model. We also aimed to compare the analgesic effects of iROE to those of mature extract (mROE) and examine the proinflammatory cytokine response and associated underlying mechanisms. : In adult male Sprague Dawley rats, acute postoperative pain was induced through plantar hind-paw incisions. After the plantar incisions were made, the rats were intraperitoneally administered with normal saline or various doses of iROE and mROE to investigate and compare the analgesic effects of iROE and mROE. The mechanisms underlying iROE-induced analgesia were investigated via post-incisional administration of yohimbine, dexmedetomidine, prazosin, naloxone, atropine, or mecamylamine, followed by iROE. Mechanical withdrawal threshold (MWT) evaluations with von Frey filaments were carried out at different time points. Serum levels of tumor necrosis factor α, interleukin (IL)-1β, and IL-6 were measured to assess inflammatory responses. Multivariate analysis of variance (MANOVA) and linear mixed-effects model (LMEM) analysis were used to analyze the analgesic effect data. : The MWTs demonstrated significant increases in iROE in a dose-dependent manner up to 2 h after the plantar incisions were made. An LMEM analysis demonstrated that iROE yielded a significantly greater analgesic effect than mROE, but there was no significant difference between the two according to MANOVA. Dexmedetomidine enhanced the MWT-confirmed iROE response, while yohimbine and naloxone diminished it. Administration of iROE significantly attenuated the post-incisional increases in serum IL-1β and IL-6 levels. : The iROE demonstrated analgesic and anti-inflammatory effects in a rat model of incisional pain, which were more pronounced than those associated with mROE. The analgesic activity of iROE may be associated with α-adrenergic and opioid receptors.
Topics: Animals; Male; Rats; Analgesics; Dexmedetomidine; Hyperalgesia; Interleukin-6; Naloxone; Pain, Postoperative; Rats, Sprague-Dawley; Rubus; Yohimbine; Plant Extracts
PubMed: 36837466
DOI: 10.3390/medicina59020264 -
British Journal of Clinical Pharmacology May 2018Establishing a pharmacological challenge model could yield an important tool to understand the complex role of the nicotinic cholinergic system in cognition and to... (Randomized Controlled Trial)
Randomized Controlled Trial
AIMS
Establishing a pharmacological challenge model could yield an important tool to understand the complex role of the nicotinic cholinergic system in cognition and to develop novel compounds acting on the nicotinic acetylcholine receptor.
METHODS
This randomized, double-blind, double-dummy, placebo-controlled, four-way crossover study examined the effects of the nicotinic antagonist mecamylamine on a battery of cognitive and neurophysiological test with coadministration of a placebo, nicotine or galantamine in order to reverse the cognitive impairment caused by mecamylamine.
RESULTS
Thirty-three healthy subjects received a single oral dose of 30 mg of mecamylamine (or placebo) in combination with either 16 mg of oral galantamine or 21 mg of transdermal nicotine (or its double-dummy). Mecamylamine 30 mg induced significant disturbances of cognitive functions. Attention and execution of visual (fine) motor tasks was decreased, short- and long-term memory was impaired and the reaction velocity during the test was slower when compared to placebo. Mecamylamine 30 mg produced a decrease in posterior α and β power in the surface electroencephalogram, effects that were reversed by nicotine coadministration. Memory and motor coordination tests could be partially reversed by the coadministration of nicotine.
CONCLUSIONS
Mecamylamine administration induced slowing of the electroencephalogram and produced decrease in performance of tests evaluating motor coordination, sustained attention and short- and long-term memory. These effects could be partially reversed by the coadministration of nicotine, and to a lesser extent by galantamine.
Topics: Adolescent; Adult; Cognition; Cross-Over Studies; Double-Blind Method; Drug Interactions; Electroencephalography; Galantamine; Healthy Volunteers; Humans; Male; Mecamylamine; Middle Aged; Nicotine; Nicotinic Agonists; Nicotinic Antagonists; Reaction Time; Young Adult
PubMed: 29319910
DOI: 10.1111/bcp.13507 -
Cell and Tissue Research Apr 2017Cigarette smoking is an important risk factor for diabetes, cardiovascular disease and non-alcoholic fatty liver disease. The health risk associated with smoking can be...
Cigarette smoking is an important risk factor for diabetes, cardiovascular disease and non-alcoholic fatty liver disease. The health risk associated with smoking can be aggravated by obesity. Smoking might also trigger cardiomyocyte (CM) apoptosis. Given that CM apoptosis has been implicated as a potential mechanism in the development of cardiomyopathy and heart failure, we characterize the key signaling pathways in nicotine plus high-fat diet (HFD)-induced CM apoptosis. Adult C57BL6 male mice were fed a normal diet (ND) or HFD and received twice-daily intraperitoneal (IP) injections of nicotine (0.75 mg/kg body weight [BW]) or saline for 16 weeks. An additional group of nicotine-treated mice on HFD received twice-daily IP injections of mecamylamine (1 mg/kg BW), a non-selective nicotinic acetylcholine receptor antagonist, for 16 weeks. Nicotine when combined with HFD led to a massive increase in CM apoptosis that was fully prevented by mecamylamine treatment. Induction of CM apoptosis was associated with increased oxidative stress and activation of caspase-2-mediated intrinsic pathway signaling coupled with inactivation of AMP-activated protein kinase (AMPK). Furthermore, nicotine treatment significantly (P < 0.05) attenuated the HFD-induced decrease in fibroblast growth factor 21 (FGF21) and silent information regulator 1 (SIRT1). We conclude that nicotine, when combined with HFD, triggers CM apoptosis through the generation of oxidative stress and inactivation of AMPK together with the activation of caspase-2-mediated intrinsic apoptotic signaling independently of FGF21 and SIRT1.
Topics: AMP-Activated Protein Kinases; Animals; Apoptosis; Caspases; Diet, High-Fat; Fibroblast Growth Factors; Immunohistochemistry; Male; Mice, Inbred C57BL; Models, Biological; Myocytes, Cardiac; Nicotine; Oxidative Stress; Phosphorylation; Sirtuin 1
PubMed: 27917437
DOI: 10.1007/s00441-016-2536-1 -
Frontiers in Cellular Neuroscience 2022Activation of nicotinic acetylcholine receptors (nAChRs) expressed by innate immune cells can attenuate pro-inflammatory responses. Silent nAChR agonists, which...
Activation of nicotinic acetylcholine receptors (nAChRs) expressed by innate immune cells can attenuate pro-inflammatory responses. Silent nAChR agonists, which down-modulate inflammation but have little or no ionotropic activity, are of outstanding clinical interest for the prevention and therapy of numerous inflammatory diseases. Here, we compare two silent nAChR agonists, phosphocholine, which is known to interact with nAChR subunits α7, α9, and α10, and CF3-N,N-diethyl-'-phenyl-piperazine (CF3-diEPP), a previously identified α7 nAChR silent agonist, regarding their anti-inflammatory properties and their effects on ionotropic nAChR functions. The lipopolysaccharide (LPS)-induced release of interleukin (IL)-6 by primary murine macrophages was inhibited by CF3-diEPP, while phosphocholine was ineffective presumably because of instability. In human whole blood cultures CF3-diEPP inhibited the LPS-induced secretion of IL-6, TNF-α and IL-1β. The ATP-mediated release of IL-1β by LPS-primed human peripheral blood mononuclear leukocytes, monocytic THP-1 cells and THP-1-derived M1-like macrophages was reduced by both phosphocholine and femtomolar concentrations of CF3-diEPP. These effects were sensitive to mecamylamine and to conopeptides RgIA4 and [V11L; V16D]ArIB, suggesting the involvement of nAChR subunits α7, α9 and/or α10. In two-electrode voltage-clamp measurements CF3-diEPP functioned as a partial agonist and a strong desensitizer of classical human α9 and α9α10 nAChRs. Interestingly, CF3-diEPP was more effective as an ionotropic agonist at these nAChRs than at α7 nAChR. In conclusion, phosphocholine and CF3-diEPP are potent agonists at unconventional nAChRs expressed by monocytic and macrophage-like cells. CF3-diEPP inhibits the LPS-induced release of pro-inflammatory cytokines, while phosphocholine is ineffective. However, both agonists signal nAChR subunits α7, α9 and/or α10 to efficiently down-modulate the ATP-induced release of IL-1β. Compared to phosphocholine, CF3-diEPP is expected to have better pharmacological properties. Thus, low concentrations of CF3-diEPP may be a therapeutic option for the treatment of inflammatory diseases including trauma-induced sterile inflammation.
PubMed: 35431807
DOI: 10.3389/fncel.2022.779081 -
Alcoholism, Clinical and Experimental... Jan 2016Ethanol (EtOH) and nicotine abuse are 2 leading causes of preventable mortality in the world, but little is known about the pharmacological mechanisms mediating...
BACKGROUND
Ethanol (EtOH) and nicotine abuse are 2 leading causes of preventable mortality in the world, but little is known about the pharmacological mechanisms mediating co-abuse. Few studies have examined the interaction of the acute effects of EtOH and nicotine. Here, we examine the effects of nicotine administration on the duration of EtOH-induced loss of righting reflex (LORR) and characterize the nature of their pharmacological interactions in C57BL/6J mice.
METHODS
We assessed the effects of EtOH and nicotine and the nature of their interaction in the LORR test using isobolographic analysis after acute injection in C57BL/6J male mice. Next, we examined the importance of receptor efficacy using nicotinic partial agonists varenicline and sazetidine. We evaluated the involvement of major nicotinic acetylcholine receptor (nAChR) subtypes using nicotinic antagonist mecamylamine and nicotinic α4- and α7-knockout mice. The selectivity of nicotine's actions on EtOH-induced LORR was examined by testing nicotine's effects on the hypnotic properties of ketamine and pentobarbital. We also assessed the development of tolerance after repeated nicotine exposure. Last, we assessed whether the effects of nicotine on EtOH-induced LORR extend to hypothermia and EtOH intake in the drinking in the dark (DID) paradigm.
RESULTS
We found that acute nicotine injection enhances EtOH's hypnotic effects in a synergistic manner and that receptor efficacy plays an important role in this interaction. Furthermore, tolerance developed to the enhancement of EtOH's hypnotic effects by nicotine after repeated exposure of the drug. α4* and α7 nAChRs seem to play an important role in nicotine-EtOH interaction in the LORR test. In addition, the magnitude of EtOH-induced LORR enhancement by nicotine was more pronounced in C57BL/6J than DBA/2J mice. Furthermore, acute nicotine enhanced ketamine and pentobarbital hypnotic effects in the mouse. Finally, nicotine enhanced EtOH-induced hypothermia but decreased EtOH intake in the DID test.
CONCLUSIONS
Our results demonstrate that nicotine synergistically enhances EtOH-induced LORR in the mouse.
Topics: Animals; Azetidines; Body Temperature; Central Nervous System Depressants; Drug Interactions; Ethanol; Hypnotics and Sedatives; Hypothermia; Ketamine; Mecamylamine; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Knockout; Nicotine; Nicotinic Agonists; Nicotinic Antagonists; Pentobarbital; Pyridines; Receptors, Nicotinic; Reflex, Righting; Varenicline; alpha7 Nicotinic Acetylcholine Receptor
PubMed: 26727524
DOI: 10.1111/acer.12918 -
Behavioural Brain Research Sep 2015The mesolimbic dopamine (DA) system is known to play a role in cue-mediated reward-seeking for natural rewards and drugs of abuse. Specifically, cholinergic and...
The mesolimbic dopamine (DA) system is known to play a role in cue-mediated reward-seeking for natural rewards and drugs of abuse. Specifically, cholinergic and glutamatergic receptors in the ventral tegmental area (VTA) have been shown to regulate cue-induced drug-seeking. However, the potential role of these VTA receptors in regulating cue-induced reward seeking for natural rewards is unknown. Here, we examined whether blockade of VTA acetylcholine receptors (AChRs) and N-methyl-d-aspartate receptors (NMDARs) would alter cue-induced sucrose seeking in male Sprague-Dawley rats. Subjects underwent 10 days of sucrose self-administration training (fixed ratio 1 schedule) followed by 7 days of forced abstinence. On withdrawal day 7, rats received bilateral VTA infusion of vehicle, the muscarinic AChR antagonist scopolamine (2.4 or 24 μg/side), the nicotinic AChR antagonist mecamylamine (3 or 30 μg/side), or the NMDAR antagonist AP-5 (0.1 or 1 μg/side) immediately prior to examination of cue-induced sucrose-seeking. Scopolamine infusion led to robust attenuation, but did not completely block, sucrose-seeking behavior. In contrast, VTA administration of mecamylamine or AP-5 did not alter cue-induced sucrose-seeking. Together, the data suggest that VTA muscarinic AChRs, but not nicotinic AChRs nor NMDARs, facilitate the ability of food-associated cues to drive seeking behavior for a food reward.
Topics: Animals; Appetitive Behavior; Cohort Studies; Conditioning, Operant; Cues; Dietary Sucrose; Dose-Response Relationship, Drug; Feeding Behavior; Male; Mecamylamine; Motivation; Muscarinic Antagonists; Neuropsychological Tests; Nicotinic Antagonists; Rats, Sprague-Dawley; Receptors, Muscarinic; Receptors, Nicotinic; Reward; Scopolamine; Self Administration; Ventral Tegmental Area
PubMed: 26026787
DOI: 10.1016/j.bbr.2015.05.036 -
Hypertension (Dallas, Tex. : 1979) Jun 2023The opioid overdose and opioid use disorder epidemics are concomitant with increased metabolic and CVD risk. Although opioid use disorder causes adverse pregnancy...
BACKGROUND
The opioid overdose and opioid use disorder epidemics are concomitant with increased metabolic and CVD risk. Although opioid use disorder causes adverse pregnancy outcomes, the offspring's cardiovascular health is understudied. We hypothesized that offspring exposed to in utero morphine exposure (IUME) would show increased CVD risk factors and endogenous opioid system dysregulation.
METHODS
Sprague Dawley dams were treated with saline (vehicle, n=10) or escalating doses of morphine (5-20 mg/kg per day, SC, n=10) during gestation. Cardiovascular and metabolic parameters were assessed in adult offspring.
RESULTS
Litter size and pups' birth weight were not different in response to IUME. Female and male IUME offspring showed reduced body length at birth (<0.05) and body weight from weeks 1 to 3 of life (<0.05), followed by a catch-up growth effect. By week 16, female and male IUME rats showed reduced tibia length (<0.05) and fat mass. IUME increases the mean arterial pressure and the depressor response to mecamylamine (5 mg/kg per day, IP) induced by IUME were abolished by a chronic treatment with an alpha-adrenergic receptor blocker (prazosin; 1 mg/kg per day, IP). Although circulating levels of angiotensin peptides were similar between groups, IUME exacerbated maximal ex vivo Ang (angiotensin) II-induced vasoconstriction (<0.05) and induced endothelial dysfunction in a sex-specific manner (<0.05). Proenkephalin, an endogenous opioid peptide that lowers blood pressure and sympathetic-mediated vasoconstriction, showed reduced mRNA expression in the heart, aorta, and kidneys from morphine versus vehicle group (<0.05).
CONCLUSIONS
Among the effects of IUME, neurogenic hypertension, vascular dysfunction, and metabolic dysfunction could be associated with the dysregulation of the endogenous opioid system.
Topics: Pregnancy; Humans; Rats; Animals; Male; Female; Morphine; Analgesics, Opioid; Rats, Sprague-Dawley; Cardiovascular Diseases; Prenatal Exposure Delayed Effects; Hypertension; Angiotensin II; Opioid-Related Disorders
PubMed: 37042247
DOI: 10.1161/HYPERTENSIONAHA.122.20262 -
Research Square Oct 2023Toxic exposures to heavy metals, such as iron (Fe) and manganese (Mn), can result in long-range neurological diseases and are therefore of significant environmental and...
Toxic exposures to heavy metals, such as iron (Fe) and manganese (Mn), can result in long-range neurological diseases and are therefore of significant environmental and medical concerns. We have previously reported that damage to neuroblastoma-derived dopaminergic cells (SH-SY5Y) by both Fe and Mn could be prevented by pre-treatment with nicotine. Moreover, butyrate, a short chain fatty acid (SCFA) provided protection against salsolinol, a selective dopaminergic toxin, in the same cell line. Here, we broadened the investigation to determine whether butyrate might also protect against Fe and/or Mn, and whether, if combined with nicotine, an additive or synergistic effect might be observed. Both butyrate and nicotine concentration-dependently blocked Fe and Mn toxicities. The ineffective concentrations of nicotine and butyrate, when combined, provided full protection against both Fe and Mn. Moreover, the effects of nicotine but not butyrate could be blocked by mecamylamine, a non-selective nicotinic antagonist. On the other hand, the effects of butyrate, but not nicotine, could be blocked by beta-hydroxy butyrate, a fatty acid-3 receptor antagonist. These results not only provide further support for neuroprotective effects of both nicotine and butyrate but indicate distinct mechanisms of action for each one. Furthermore, potential utility of the combination of butyrate and nicotine against heavy metal toxicities is suggested.
PubMed: 37886507
DOI: 10.21203/rs.3.rs-3389904/v1 -
Diabetes Nov 2019The contribution of the sympathetic nervous system (SNS) versus the parasympathetic nervous system (PSNS) in mediating fatal cardiac arrhythmias during insulin-induced...
The contribution of the sympathetic nervous system (SNS) versus the parasympathetic nervous system (PSNS) in mediating fatal cardiac arrhythmias during insulin-induced severe hypoglycemia is not well understood. Therefore, experimental protocols were performed in nondiabetic Sprague-Dawley rats to test the SNS with ) adrenal demedullation and ) chemical sympathectomy, and to test the PSNS with ) surgical vagotomy, ) nicotinic receptor (mecamylamine) and muscarinic receptor (AQ-RA 741) blockade, and ) ex vivo heart perfusions with normal or low glucose, acetylcholine (ACh), and/or mecamylamine. In protocols 1-4, 3-h hyperinsulinemic (0.2 units/kg/min) and hypoglycemic (10-15 mg/dL) clamps were performed. Adrenal demedullation and chemical sympathectomy had no effect on mortality or arrhythmias during severe hypoglycemia compared with controls. Vagotomy led to a 6.9-fold decrease in mortality; reduced first- and second-degree heart block 4.6- and 4-fold, respectively; and prevented third-degree heart block compared with controls. Pharmacological blockade of nicotinic receptors, but not muscarinic receptors, prevented heart block and mortality versus controls. Ex vivo heart perfusions demonstrated that neither low glucose nor ACh alone caused arrhythmias, but their combination induced heart block that could be abrogated by nicotinic receptor blockade. Taken together, ACh activation of nicotinic receptors via the vagus nerve is the primary mediator of severe hypoglycemia-induced fatal cardiac arrhythmias.
Topics: Animals; Arrhythmias, Cardiac; Benzodiazepinones; Disease Models, Animal; Hypoglycemia; Male; Mecamylamine; Muscarinic Antagonists; Nicotinic Antagonists; Parasympathetic Nervous System; Piperidines; Rats; Rats, Sprague-Dawley; Sympathectomy, Chemical; Vagotomy
PubMed: 31439645
DOI: 10.2337/db19-0306