1
|
Tae HS, Adams DJ. Nicotinic acetylcholine receptor subtype expression, function, and pharmacology: Therapeutic potential of α-conotoxins. Pharmacol Res 2023; 191:106747. [PMID: 37001708 DOI: 10.1016/j.phrs.2023.106747] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/22/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023]
Abstract
The pentameric nicotinic acetylcholine receptors (nAChRs) are typically classed as muscle- or neuronal-type, however, the latter has also been reported in non-neuronal cells. Given their broad distribution, nAChRs mediate numerous physiological and pathological processes including synaptic transmission, presynaptic modulation of transmitter release, neuropathic pain, inflammation, and cancer. There are 17 different nAChR subunits and combinations of these subunits produce subtypes with diverse pharmacological properties. The expression and role of some nAChR subtypes have been extensively deciphered with the aid of knock-out models. Many nAChR subtypes expressed in heterologous systems are selectively targeted by the disulfide-rich α-conotoxins. α-Conotoxins are small peptides isolated from the venom of cone snails, and a number of them have potential pharmaceutical value.
Collapse
|
2
|
α-Conotoxin TxID and [S9K]TxID, α3β4 nAChR Antagonists, Attenuate Expression and Reinstatement of Nicotine-Induced Conditioned Place Preference in Mice. Mar Drugs 2020; 18:md18120646. [PMID: 33339145 PMCID: PMC7765617 DOI: 10.3390/md18120646] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/09/2020] [Accepted: 12/12/2020] [Indexed: 01/14/2023] Open
Abstract
Tobacco smoking has become a prominent health problem faced around the world. The α3β4 nicotinic acetylcholine receptor (nAChR) is strongly associated with nicotine reward and withdrawal symptom. α-Conotoxin TxID, cloned from Conus textile, is a strong α3β4 nAChR antagonist, which has weak inhibition activity of α6/α3β4 nAChR. Meanwhile, its analogue [S9K]TxID only inhibits α3β4 nAChR (IC50 = 6.9 nM), and has no inhibitory activity to other nAChRs. The present experiment investigates the effect of α3β4 nAChR antagonists (TxID and [S9K]TxID) on the expression and reinstatement of nicotine-induced conditioned place preference (CPP) and explores the behaviors of acute nicotine in mice. The animal experimental results showed that TxID and [S9K] TxID could inhibit the expression and reinstatement of CPP, respectively. Moreover, both had no effect in acute nicotine experiment and the locomotor activity in mice. Therefore, these findings reveal that the α3β4 nAChR may be a potential target for anti-nicotine addiction treatment. [S9K]TxID, α3β4 nAChR antagonist, exhibit a superior effect for anti-nicotine addiction, which is promising to develop a novel smoking cessation drug.
Collapse
|
3
|
Vanderstocken G, Marrow JP, Allwood MA, Stampfli MR, Simpson JA. Disruption of Physiological Rhythms Persist Following Cessation of Cigarette Smoke Exposure in Mice. Front Physiol 2020; 11:501383. [PMID: 33192539 PMCID: PMC7609783 DOI: 10.3389/fphys.2020.501383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 09/28/2020] [Indexed: 01/29/2023] Open
Abstract
Background Physiological rhythms in mammals are essential for maintaining health, whereas disruptions may cause or exacerbate disease pathogenesis. As such, our objective was to characterize how cigarette smoke exposure affects physiological rhythms of otherwise healthy mice using telemetry and cosinor analysis. Methods Female BALB/c mice were implanted with telemetry devices to measure body temperature, heart rate, systolic blood pressure (SBP), and activity. Following baseline measurements, mice were exposed to cigarette smoke for approximately 50 min twice daily during weekdays over 24 weeks. Physiological parameters were recorded after 1, 4, 8, and 24 weeks of exposure or after 4 weeks cessation following 4 weeks of cigarette smoke exposure. Results Acute cigarette smoke exposure resulted in anapyrexia, and bradycardia, with divergent effects on SBP. Long term, cigarette smoke exposure disrupted physiological rhythms after just 1 week, which persisted across 24 weeks of exposure (as shown by mixed effects on mesor, amplitude, acrophase, and goodness-of-fit using cosinor analysis). Four weeks of cessation was insufficient to allow full recovery of rhythms. Conclusion Our characterization of the pathophysiology of cigarette smoke exposure on physiological rhythms of mice suggests that rhythm disruption may precede and contribute to disease pathogenesis. These findings provide a clear rationale and guide for the future use of chronotherapeutics.
Collapse
Affiliation(s)
- Gilles Vanderstocken
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Centre, McMaster University, Hamilton, ON, Canada.,Department of Medicine, Firestone Institute for Respiratory Health at St. Joseph's Healthcare, McMaster University, Hamilton, ON, Canada
| | - Jade P Marrow
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada.,IMPART Team Canada Investigator Network, Guelph, ON, Canada
| | - Melissa A Allwood
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Martin R Stampfli
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Centre, McMaster University, Hamilton, ON, Canada.,Department of Medicine, Firestone Institute for Respiratory Health at St. Joseph's Healthcare, McMaster University, Hamilton, ON, Canada.,State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
| | - Jeremy A Simpson
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada.,IMPART Team Canada Investigator Network, Guelph, ON, Canada
| |
Collapse
|
4
|
Seoane-Collazo P, Diéguez C, Nogueiras R, Rahmouni K, Fernández-Real JM, López M. Nicotine' actions on energy balance: Friend or foe? Pharmacol Ther 2020; 219:107693. [PMID: 32987056 DOI: 10.1016/j.pharmthera.2020.107693] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 09/21/2020] [Indexed: 12/12/2022]
Abstract
Obesity has reached pandemic proportions and is associated with severe comorbidities, such as type 2 diabetes mellitus, hepatic and cardiovascular diseases, and certain cancer types. However, the therapeutic options to treat obesity are limited. Extensive epidemiological studies have shown a strong relationship between smoking and body weight, with non-smokers weighing more than smokers at any age. Increased body weight after smoking cessation is a major factor that interferes with their attempts to quit smoking. Numerous controlled studies in both humans and rodents have reported that nicotine, the main bioactive component of tobacco, exerts a marked anorectic action. Furthermore, nicotine is also known to modulate energy expenditure, by regulating the thermogenic activity of brown adipose tissue (BAT) and the browning of white adipose tissue (WAT), as well as glucose homeostasis. Many of these actions occur at central level, by controlling the activity of hypothalamic neuropeptide systems such as proopiomelanocortin (POMC), or energy sensors such as AMP-activated protein kinase (AMPK). However, direct impact of nicotine on metabolic tissues, such as BAT, WAT, liver and pancreas has also been described. Here, we review the actions of nicotine on energy balance. The relevance of this interaction is interesting, because considering the restricted efficiency of obesity treatments, a possible complementary approach may focus on compounds with known pharmacokinetic profile and pharmacological actions, such as nicotine or nicotinic acetylcholine receptors signaling.
Collapse
Affiliation(s)
- Patricia Seoane-Collazo
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain; International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan.
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Rubén Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine and Veterans Affairs Health Care System, Iowa City, IA 52242, USA
| | - José Manuel Fernández-Real
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Department of Diabetes, Endocrinology and Nutrition (UDEN), Hospital of Girona "Dr Josep Trueta" and Department of Medical Sciences, Faculty of Medicine, University of Girona, Girona, Spain
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain.
| |
Collapse
|
5
|
Chellian R, Pandy V. Protective effect of α-asarone against nicotine-induced seizures in mice, but not by its interaction with nicotinic acetylcholine receptors. Biomed Pharmacother 2018; 108:1591-1595. [DOI: 10.1016/j.biopha.2018.09.137] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/23/2018] [Accepted: 09/24/2018] [Indexed: 12/27/2022] Open
|
6
|
Coordinated targeting of cold and nicotinic receptors synergistically improves obesity and type 2 diabetes. Nat Commun 2018; 9:4304. [PMID: 30353008 PMCID: PMC6199300 DOI: 10.1038/s41467-018-06769-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 08/27/2018] [Indexed: 12/19/2022] Open
Abstract
Pharmacological stimulation of brown adipose tissue (BAT) thermogenesis to increase energy expenditure is progressively being pursued as a viable anti-obesity strategy. Here, we report that pharmacological activation of the cold receptor transient receptor potential cation channel subfamily M member 8 (TRPM8) with agonist icilin mimics the metabolic benefits of cold exposure. In diet-induced obese (DIO) mice, treatment with icilin enhances energy expenditure, and decreases body weight, without affecting food intake. To further potentiate the thermogenic action profile of icilin and add complementary anorexigenic mechanisms, we set out to identify pharmacological partners next to icilin. To that end, we specifically targeted nicotinic acetylcholine receptor (nAChR) subtype alpha3beta4 (α3β4), which we had recognized as a potential regulator of energy homeostasis and glucose metabolism. Combinatorial targeting of TRPM8 and nAChR α3β4 by icilin and dimethylphenylpiperazinium (DMPP) orchestrates synergistic anorexic and thermogenic pathways to reverse diet-induced obesity, dyslipidemia, and glucose intolerance in DIO mice. Tobacco smoking and cold exposure are environmental modulators of human energy metabolism suppressing appetite and increasing energy expenditure, respectively. Here, the authors develop a novel pharmacological strategy in which they simultaneously mimic the metabolic benefits of both phenomena through small-molecule combination therapy, and show that this treatment improves metabolic health of obese mice.
Collapse
|
7
|
Avraam J, Cummings KJ, Frappell PB. α4-Containing nicotinic receptors contribute to the effects of perinatal nicotine on ventilatory and metabolic responses of neonatal mice to ambient cooling. Am J Physiol Regul Integr Comp Physiol 2016; 311:R727-R734. [PMID: 27511281 DOI: 10.1152/ajpregu.00247.2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/27/2016] [Accepted: 08/03/2016] [Indexed: 11/22/2022]
Abstract
Among numerous studies, perinatal nicotine exposure (PN) has had variable effects on respiratory control in the neonatal period. The effects of acute nicotine exposure on breathing are largely mediated by α4-containing nicotine acetylcholine receptors (nAChRs). These receptors are also involved in thermoregulatory responses induced by both acetylcholine and nicotine. We therefore hypothesized that α4-containing nAChRs would mediate the effects of PN on the metabolic and ventilatory responses of neonates to modest cold exposure. Wild-type (WT) and α4 knockout (KO) mice were exposed to 6 mg·kg-1·day-1 nicotine or vehicle from embryonic day 14 At postnatal day (P) 7 mice were cooled from an ambient temperature (TA) of 32 to 20°C. Body temperature (TB), rate of O2 consumption (V̇o2), ventilation (V̇e), respiratory frequency (FB), and tidal volume (VT) were continually monitored. An absence of α4 had no effect on the metabolic response to ambient cooling. Surprisingly, PN selectively increased the metabolic response of KO pups to cooling. Regardless, KO pups became hypothermic to the same degree as WT pups, and for both genotypes the drop in TB was exacerbated by PN. PN led to hyperventilation in WT pups caused by an increase in VT, an effect that was absent in α4 KO littermates. We show that PN interacts with α4-containing nAChRs in unique ways to modulate the control of breathing and thermoregulation in the early postnatal period.
Collapse
Affiliation(s)
- Joanne Avraam
- Department of Zoology, La Trobe University, Melbourne, Victoria, Australia; .,Department of Psychological Sciences, University of Melbourne, Victoria, Australia; and
| | - Kevin J Cummings
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - Peter B Frappell
- Department of Zoology, La Trobe University, Melbourne, Victoria, Australia
| |
Collapse
|
8
|
Sex differences in thermogenesis structure behavior and contact within huddles of infant mice. PLoS One 2014; 9:e87405. [PMID: 24498099 PMCID: PMC3909189 DOI: 10.1371/journal.pone.0087405] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 12/24/2013] [Indexed: 11/19/2022] Open
Abstract
Brown adipose tissue (BAT) is a thermogenic effector abundant in most mammalian infants. For multiparous species such as rats and mice, the interscapular BAT deposit provides both an emergency "thermal blanket" and a target for nestmates seeking warmth, thereby increasing the cohesiveness of huddling groups. Sex differences in BAT regulation and thermogenesis have been documented in a number of species, including mice (Mus musculus)--with females generally exhibiting relative upregulation of BAT. It is nonetheless unknown whether this difference affects the behavioral dynamics occurring within huddles of infant rodents. We investigated sex differences in BAT thermogenesis and its relation to contact while huddling in eight-day-old C57BL/6 mouse pups using infrared thermography, scoring of contact, and causal modeling of the relation between interscapular temperature relative to other pups in the huddle (T IS (rel)) and contacts while huddling. We found that females were warmer than their male siblings during cold challenge, under conditions both in which pups were isolated and in which pups could actively huddle in groups of six (3 male, 3 female). This difference garnered females significantly more contacts from other pups than males during cold-induced huddling. Granger analyses revealed a significant negative feedback relationship between contacts with males and T IS (rel) for females, and positive feedback between contacts with females and T IS (rel) for males, indicating that male pups drained heat from female siblings while huddling. Significant sex assortment nonetheless occurred, such that females made more contacts with other females than expected by chance, apparently outcompeting males for access to each other. These results provide further evidence of enhanced BAT thermogenesis in female mice. Slight differences in BAT can significantly structure the behavioral dynamics occurring in huddles, resulting in differences in the quantity and quality of contacts obtained by the individuals therein, creating sex differences in behavioral interactions beginning in early infancy.
Collapse
|
9
|
Levin ED, Sexton HG, Gordon K, Gordon CJ, Xiao Y, Kellar KJ, Yenugonda VM, Liu Y, White MP, Paige M, Brown ML, Rezvani AH. Effects of the sazetidine-a family of compounds on the body temperature in wildtype, nicotinic receptor β2-/- and α7-/- mice. Eur J Pharmacol 2013; 718:167-72. [PMID: 24036108 DOI: 10.1016/j.ejphar.2013.08.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 08/21/2013] [Accepted: 08/30/2013] [Indexed: 10/26/2022]
Abstract
Nicotine elicits hypothermic responses in rodents. This effect appears to be related to nicotinic receptor desensitization because sazetidine-A, an α4β2 nicotinic receptor desensitizing agent, produces marked hypothermia and potentiates nicotine-induced hypothermia in mice. To determine the specificity of sazetidine-A induced hypothermia to β2 subunit-containing nicotinic receptors, we tested its efficacy in β2 knockout (β2(-/-)) mice. These effects were compared with wildtype (WT) and α7 knockout (α7(-/-)) mice. Confirming our earlier results, sazetidine-A elicited a pronounced and long-lasting hypothermia in WT mice. In comparison, sazetidine-A induced a much attenuated and shorter hypothermic response in β2(-/-) mice. This indicates that the greater proportion of sazetidine-A induced hypothermia is mediated via actions on β2-containing nicotinic receptors, while a smaller component of hypothermia induced by sazetidine-A is mediated by non-β2 receptors. Similar to WT mice, α7(-/-) mice showed the full extent of the sazetidine-A effect, suggesting that the hypothermia produced by sazetidine-A did not depend on actions on α7 nicotinic receptor subtype. Three other novel nicotinic receptor desensitizing agents derived from sazetidine-A, triazetidine-O, VMY-2-95 and YL-1-127 also produced hypothermia in WT and α7(-/-) mice. Furthermore, unlike sazetidine-A, triazetidine-O and YL-1-127 did not show any hint of a hypothermic effect in β2(-/-) mice. VMY-2-95 like sazetidine-A did show a residual hypothermic effect in the β2(-/-) mice. These studies show that the hypothermic effects of sazetidine-A and the related compound VMY-2-95 are mainly mediated by nicotinic receptors containing β2 subunit, but that a small component of the effect is apparently mediated by non-β2 containing receptors.
Collapse
Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Freitas K, Negus SS, Carroll FI, Damaj MI. In vivo pharmacological interactions between a type II positive allosteric modulator of α7 nicotinic ACh receptors and nicotinic agonists in a murine tonic pain model. Br J Pharmacol 2013; 169:567-79. [PMID: 23004024 PMCID: PMC3682705 DOI: 10.1111/j.1476-5381.2012.02226.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 08/09/2012] [Accepted: 08/29/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The α7 nicotinic ACh receptor subtype is abundantly expressed in the CNS and in the periphery. Recent evidence suggests that α7 nicotinic ACh receptor (nAChR) subtypes, which can be activated by an endogenous cholinergic tone comprising ACh and the α7 agonist choline, play an important role in chronic pain and inflammation. In this study, we evaluated whether type II α7 positive allosteric modulator PNU-120596 induces antinociception on its own and in combination with choline in the formalin pain model. EXPERIMENTAL APPROACH We assessed the effects of PNU-120596 and choline and the nature of their interactions in the formalin test using an isobolographic analysis. In addition, we evaluated the interaction of PNU-120596 with PHA-54613, an exogenous selective α7 nAChR agonist, in the formalin test. Finally, we assessed the interaction between PNU-120596 and nicotine using acute thermal pain, locomotor activity, body temperature and convulsing activity tests in mice. KEY RESULTS We found that PNU-120596 dose-dependently attenuated nociceptive behaviour in the formalin test after systemic administration in mice. In addition, mixtures of PNU-120596 and choline synergistically reduced formalin-induced pain. PNU-120596 enhanced the effects of nicotine and α7 agonist PHA-543613 in the same test. In contrast, PNU-120596 failed to enhance nicotine-induced convulsions, hypomotility and antinociception in acute pain models. Surprisingly, it enhanced nicotine-induced hypothermia via activation of α7 nAChRs. CONCLUSIONS AND IMPLICATIONS Our results demonstrate that type II α7 positive allosteric modulators produce antinociceptive effects in the formalin test through a synergistic interaction with the endogenous α7 agonist choline.
Collapse
Affiliation(s)
- K Freitas
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298-0613, USA
| | | | | | | |
Collapse
|
11
|
Jackson KJ, Sanjakdar SS, Muldoon PP, McIntosh JM, Damaj MI. The α3β4* nicotinic acetylcholine receptor subtype mediates nicotine reward and physical nicotine withdrawal signs independently of the α5 subunit in the mouse. Neuropharmacology 2013; 70:228-35. [PMID: 23416040 DOI: 10.1016/j.neuropharm.2013.01.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 01/05/2013] [Accepted: 01/12/2013] [Indexed: 11/19/2022]
Abstract
The 15q25 gene cluster contains genes that code for the α5, α3, and β4 nicotinic acetylcholine receptor (nAChRs) subunits, and in human genetic studies, has shown the most robust association with smoking behavior and nicotine dependence to date. The limited available animal studies implicate a role for the α5 and β4 nAChR subunits in nicotine dependence and withdrawal; however studies focusing on the behavioral role of the α3β4* nAChR receptor subtype in nicotine dependence are lacking. Because of the apparent role of the α3β4* nAChR subtype in nicotine dependence, the goal of the current study was to better evaluate the involvement of this subtype in nicotine mediated behavioral responses. Using the selective α3β4* nAChR antagonist, α-conotoxin AuIB, we assessed the role of α3β4* nAChRs in acute nicotine, nicotine reward, and physical and affective nicotine withdrawal. Because α5 has also been implicated in nicotine dependence behaviors in mice and can form functional receptors with α3β4*, we also evaluated the role of the α3β4α5* nAChR subtype in nicotine reward and somatic nicotine withdrawal signs by blocking the α3β4* nAChR subtype in α5 nAChR knockout mice with AuIB. AuIB had no significant effect on acute nicotine behaviors, but dose-dependently attenuated nicotine reward and physical withdrawal signs, with no significant effect in affective withdrawal measures. Interestingly, AuIB also attenuated nicotine reward and somatic signs in α5 nAChR knockout mice. This study shows that α3β4* nAChRs mediate nicotine reward and physical nicotine withdrawal, but not acute nicotine behaviors or affective nicotine withdrawal signs in mice. The α5 subunit is not required in the receptor assembly to mediate these effects. Our findings suggest an important role for the α3β4* nAChR subtype in nicotine reward and physical aspects of the nicotine withdrawal syndrome.
Collapse
Affiliation(s)
- Kia J Jackson
- Department of Psychiatry, Virginia Commonwealth University, 800 E. Leigh St., Biotech I, Suite 390A, Richmond, VA 23219, USA
| | | | | | | | | |
Collapse
|
12
|
Gochberg-Sarver A, Kedmi M, Gana-Weisz M, Bar-Shira A, Orr-Urtreger A. Tnfα, Cox2 and AdipoQ adipokine gene expression levels are modulated in murine adipose tissues by both nicotine and nACh receptors containing the β2 subunit. Mol Genet Metab 2012; 107:561-70. [PMID: 22926197 DOI: 10.1016/j.ymgme.2012.08.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 08/08/2012] [Indexed: 12/24/2022]
Abstract
Studies have provided evidences for the effects of nicotine on adipose tissues, as well as in inflammatory response. We hypothesized that nicotine affects adipokine gene expression in adipose tissues via specific neuronal nicotinic acetylcholine receptors (nAChRs). First, we described the expression of multiple nAChR subunit genes in mouse white and brown adipose tissues (WAT and BAT), and detected differential expression in WAT and BAT (α2>α5>β2 and α2>β2>β4, respectively). Additionally, when nicotine was administered to wild-type mice, it significantly affected the expression of adipokine genes, such as Tnfα, AdipoQ, Haptoglobin and Mcp1 in WAT. Next, we demonstrated that in mice deficient for the β2 nAChR subunit (β2-/- mice), the expression levels of Cox2 and Ngfβ genes in WAT, and Leptin, Cox2, AdipoQ and Haptoglobin in BAT, were significantly altered. Furthermore, interactions between mouse β2 subunit and nicotine treatment affected the expression levels of the adipokine genes Tnfα, Cox2 and AdipoQ in WAT and of AdipoQ in BAT. Finally, analysis of a cellular model of cultured adipocytes demonstrated that application of nicotine after silencing of the β2 nAChR subunit significantly elevated the expression level of Cox2 gene. Together, our data suggest a molecular link between the β2 nACh receptor subunit and the expression levels of specific adipokines, which is also affected by nicotine.
Collapse
|
13
|
Uchiumi O, Kasahara Y, Fukui A, Hall FS, Uhl GR, Sora I. Serotonergic involvement in the amelioration of behavioral abnormalities in dopamine transporter knockout mice by nicotine. Neuropharmacology 2012; 64:348-56. [PMID: 22809709 DOI: 10.1016/j.neuropharm.2012.07.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 07/05/2012] [Accepted: 07/06/2012] [Indexed: 11/19/2022]
Abstract
Dopamine transporter knockout (DAT KO) mice exhibit elevated extracellular dopamine levels in brain regions that include the striatum and the nucleus accumbens, but not the prefrontal cortex. DAT KO mice model some aspects of psychiatric disorders, including schizophrenia. Smoking is more common in patients with schizophrenia, suggesting that nicotine might ameliorate aspects of the behavioral abnormalities and/or treatment side effects seen in these individuals. We report nicotine-induced normalization of effects on locomotion and prepulse inhibition of acoustic startle (PPI) in DAT KO mice that require intact serotonin 5-HT1A systems. First, we observed that the marked hyperactivity displayed by DAT KO mice was reduced by administration of nicotine. This nicotine effect was blocked by pretreatment with the non-specific nicotinic acetylcholine (nACh) receptor antagonist mecamylamine, or the 5-HT1A antagonist WAY100635. Secondly, we examined the effects of nicotine on PPI in DAT KO mice. Treatment with nicotine significantly ameliorated the PPI deficits observed in DAT KO mice. The ameliorating action of nicotine on PPI deficits in DAT KO mice was blocked by mecamylamine, the α₇ nACh receptor antagonist methyllycaconitine or WAY100635, while the α₄β₂ nACh receptor antagonist dihydro-β-erythroidinehydrobromide (DHβE) produced only a non-significant trend toward attenuation of nicotine effects. Finally, we observed that administration of the 5-HT1A receptor agonist 8-OH-DPAT also ameliorated the deficit in PPI observed in DAT KO mice. This amelioration was antagonized by pretreatment with WAY100635. These data support the idea that nicotine might ameliorate some of the cognitive dysfunctions found in schizophrenia in a 5-HT1A-dependent fashion. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
Collapse
Affiliation(s)
- Osamu Uchiumi
- Department of Biological Psychiatry, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Sendai 980-8574, Japan
| | | | | | | | | | | |
Collapse
|
14
|
Semenova S, Contet C, Roberts AJ, Markou A. Mice lacking the β4 subunit of the nicotinic acetylcholine receptor show memory deficits, altered anxiety- and depression-like behavior, and diminished nicotine-induced analgesia. Nicotine Tob Res 2012; 14:1346-55. [PMID: 22573727 DOI: 10.1093/ntr/nts107] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
RATIONALE The role of β4-containing nicotinic acetylcholine receptors (nAChRs) in cognition, anxiety, depression, and analgesia in the absence of nicotine is unclear. METHODS Wild-type (β4(+/+)) and knockout (β4(-/-)) mice for the nAChR β4 subunit were tested in behavioral tests assessing cognitive function, affective behaviors, and nociception. RESULTS There were no learning and memory deficits in β4(-/-) mice compared with β4(+/+) mice during the acquisition of the Barnes maze, contextual fear conditioning, and Y maze tasks. In the Barnes maze memory retention test, male β4(-/-) mice showed reduced use of the spatial search strategy, indicating small spatial memory deficits compared with β4(+/+) mice. In the cue-induced fear conditioning memory retention test, β4(-/-) mice exhibited reduced freezing time compared with β4(+/+) mice. Compared with β4(+/+) mice, β4(-/-) mice exhibited decreased anxiety-like behavior in the light-dark box. Depression-like behavior in β4(-/-) mice was decreased in the tail suspension test and increased in the forced swim test compared with β4(+/+) mice. β4(-/-) mice did not differ from β4(+/+) mice in basal nociception but were less sensitive to the antinociceptive effect of nicotine in 2 tests of acute thermal pain. CONCLUSIONS Lack of β4-containing nAChRs resulted in small deficits in hippocampus- and amygdala-dependent memory retention functions. β4-containing nAChRs are involved in anxiety- and depression-like behaviors and contribute to the analgesic effects of nicotine.
Collapse
Affiliation(s)
- Svetlana Semenova
- Department of Psychiatry, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0603, USA
| | | | | | | |
Collapse
|
15
|
Rezvani AH, Timofeeva O, Sexton HG, DeCuir D, Xiao Y, Gordon CJ, Kellar KJ, Levin ED. Effects of sazetidine-A, a selective α4β2* nicotinic receptor desensitizing agent, on body temperature regulation in mice and rats. Eur J Pharmacol 2012; 682:110-7. [PMID: 22387853 DOI: 10.1016/j.ejphar.2012.02.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 02/07/2012] [Accepted: 02/15/2012] [Indexed: 01/06/2023]
Abstract
Nicotine-induced hypothermia is well established, but the nicotinic receptor actions underlying this effect are not clear. Nicotine causes activation and desensitization at a variety of nicotinic receptor subtypes. Sazetidine-A [6-(5(((S)-azetidine-2-yl)methoxy)pyridine-3-yl)hex-5-yn-1-ol] is a novel compound that potently and selectively desensitizes α4β2* nicotinic receptors. The main goal of this study was to investigate the effects of sazetidine-A, on core body temperature (Tc) in mice and rats. Sazetidine-A effects on Tc and the interactions of sazetidine-A with nicotine and selective nicotinic antagonists were investigated to determine the receptor actions underlying nicotine-induced hypothermia. Adult male mice were injected with different dose of nicotine (0.2, 0.4 and 0.8 mg/kg), sazetidine-A (0.3, 1, and 3mg/kg), a mixture of nicotine (0.4 or 0.8 mg/kg) and sazetidine-A (0.3 or 0.6 mg/kg) or saline and Tc was monitored telemetrically. In another set of experiments, the interaction between sazetidine-A and dihydro-β-erythroidine (DHβE), an α4β2* nicotinic receptors antagonist, and methyllycaconitine (MLA), an α7 antagonist, was investigated. Tc of mice was monitored following DHβE (1, 3 and 6 mg/kg), a combination of DHβE (3mg/kg) and sazetidine-A (0.6 mg/kg), MLA (1.5, 3 or 6 mg/kg) or combination of MLA (6 mg/kg) and sazetidine (0.6 mg/kg) or saline. The acute effect of sazetidine-A (1, 3, and 6 mg/kg) on rats Tc was also studied. Acute sazetidine-A caused a pronounced and long-lasting hypothermia in mice; Tc decreased to about 28°C at 100 min and recovered within 230 min. The hypothermic effect of sazetidine in rats was much less in magnitude (about 3°C) and shorter in duration compared with that in mice. Nicotine co-administration with low doses of sazetidine potentiated the magnitude and duration of hypothermia in mice. The α4β2* nicotinic receptors antagonist DHβE significantly prolonged sazetidine-A-induced hypothermia but did not increase its depth. The α7 antagonist MLA caused a modest degree of hypothermia with relatively short duration in mice. MLA failed to counteract the sazetidine-A-induced hypothermia. Overall, our results show that pharmacological modulation of α4β2* nicotinic receptors elicits changes in body temperature that may involve desensitization of these receptors.
Collapse
Affiliation(s)
- Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA.
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Role of α7- and β4-containing nicotinic acetylcholine receptors in the affective and somatic aspects of nicotine withdrawal: studies in knockout mice. Behav Genet 2011; 42:423-36. [PMID: 22009521 DOI: 10.1007/s10519-011-9511-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 10/08/2011] [Indexed: 10/16/2022]
Abstract
To assess which nicotinic acetylcholine receptors (nAChRs) are involved in the aversive aspects of nicotine withdrawal, brain reward function and the somatic signs of nicotine withdrawal were assessed in mice that lack α7 and β4 nAChR subunits. Brain reward function was assessed with the intracranial self-stimulation (ICSS) procedure, in which elevations in ICSS thresholds reflect an anhedonic mood state. At 3-6 h of spontaneous nicotine/saline withdrawal, thresholds were elevated in nicotine-withdrawing α7(+/+) and β4(+/+), but not α7(-/-) or β4(-/-), mice compared with saline-withdrawing mice, indicating a delay in the onset of withdrawal in the knockout mice. From 8 to 100 h of withdrawal, thresholds in α7(+/+) and α7(-/-) mice were equally elevated, whereas thresholds in β4(+/+) and β4(-/-) mice returned to baseline levels. Somatic signs were attenuated in nicotine-withdrawing β4(-/-), but not α7(-/-), mice. Administration of a low dose of the nAChR antagonist mecamylamine induced threshold elevations in α7(-/-), but not α7(+/+), mice, whereas the highest dose tested only elevated thresholds in α7(+/+) mice. Mecamylamine-induced threshold elevations were similar in β4(-/-) and β4(+/+) mice. In conclusion, null mutation of the α7 and β4 nAChR subunits resulted in a delayed onset of the anhedonic aspects of the spontaneous nicotine withdrawal syndrome. Previous findings of attenuated somatic signs of nicotine withdrawal in β4(-/-), but not α7(-/-), mice were confirmed in the present study, indicating an important role for β4-containing nAChRs in the somatic signs of nicotine withdrawal. The mecamylamine-precipitated withdrawal data suggest that compensatory adaptations may occur in constitutive α7(-/-) mice or that mecamylamine may interact with other receptors besides nAChRs in these mice. In summary, the present results indicate an important role for α7 and β4-containing nAChRs in the anhedonic or somatic signs of nicotine withdrawal.
Collapse
|
17
|
Kedmi M, Orr-Urtreger A. The effects of aging vs. α7 nAChR subunit deficiency on the mouse brain transcriptome: aging beats the deficiency. AGE (DORDRECHT, NETHERLANDS) 2011; 33:1-13. [PMID: 20526689 PMCID: PMC3063643 DOI: 10.1007/s11357-010-9155-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 05/17/2010] [Indexed: 05/12/2023]
Abstract
Aging is accompanied by expression changes in multiple genes, and the brain is one of the tissues most vulnerable to aging. Since the α7 nicotinic acetylcholine receptor (nAChR) subunit has been associated with neurodevelopmental disorders and cognitive decline during aging, we hypothesized that its absence might affect gene expression profiles in aged brains. To study whether transcriptional changes occur due to aging, α7 deficiency, or both, we analyzed whole-brain transcriptomes of young (8 weeks) and aged (2 years) α7-deficient and wild-type control mice, using Mouse Genome 430 2.0 microarray. Highly significant expression changes were detected in 47 and 1,543 genes [after Bonferroni and false discovery rate (FDR) correction] in the brains of aged mice compared to young mice, regardless of their genotype. These included genes involved in immune system function and ribosome structure, as well as genes that were previously demonstrated as differentially expressed in aging human brains. Genotype-dependent changes were detected in only three genes, Chrna7 which encodes the α7 nAChR subunit, and two closely linked genes, likely due to a "mouse background effect." Expression changes dependent on age-genotype interaction were detected in 207 genes (with a low significance threshold). Age-dependent differential expression levels were approved in all nine genes that were chosen for validation by real-time RT-PCR. Our results suggest that the robust effect of aging on brain transcription clearly overcomes the almost negligible effect of α7 nAChR subunit deletion and that germ line deficiency of this subunit has a minor effect on brain expression profile in aged mice.
Collapse
Affiliation(s)
- Merav Kedmi
- Genetic Institute, Tel Aviv Sourasky Medical Center, 6 Weizmann Street, Tel Aviv, 64239 Israel
| | - Avi Orr-Urtreger
- Genetic Institute, Tel Aviv Sourasky Medical Center, 6 Weizmann Street, Tel Aviv, 64239 Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
18
|
Abdrakhmanova GR, Blough BE, Nesloney C, Navarro HA, Damaj MI, Carroll FI. In vitro and in vivo characterization of a novel negative allosteric modulator of neuronal nAChRs. Neuropharmacology 2010; 59:511-7. [PMID: 20633568 DOI: 10.1016/j.neuropharm.2010.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 06/30/2010] [Accepted: 07/05/2010] [Indexed: 11/16/2022]
Abstract
In this study, we compared the in vitro and in vivo neuronal nicotinic acetylcholine receptor (nAChR) properties of 1,2,3,3a,4,8b-hexahydro-2-benzyl-6-N,N-dimethylamino-1-methylindeno[1,2,-b]pyrrole (HDMP, 4) to that of negative allosteric modulator (NAM), PCP. Patch-clamp experiments showed that HDMP exhibited an inhibitory functional activity at α7 nAChRs with an IC(50) of 0.07 μM, and was 357- and 414-fold less potent at α4β2 and α3β4 nAChRs, with IC(50)s of 25.1 and 29.0 μM, respectively. Control patch-clamp experiments showed that PCP inhibited α7, α4β2 and α3β4 nAChRs with IC(50)s of to 1.3, 29.0 and 6.4 μM, respectively. Further, HDMP did not exhibit any appreciable binding affinity to either α7 or α4β2 nAChRs, suggesting its action via a non-competitive mechanism at these neuronal nAChR subtypes. The in vivo study showed that HDMP was a potent antagonist of nicotine-induced analgesia in the tail-flick (AD(50)=0.008 mg/kg), but not in the hot-plate test. All together, our in vitro and in vivo data suggest that HDMP is a novel NAM of neuronal nAChRs with potent inhibitory activity at α7 nAChR subtype at concentrations ≤ 1μM that are not effective for α4β2 and α3β4 nAChRs.
Collapse
Affiliation(s)
- Galya R Abdrakhmanova
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 1112 E. Clay Str., P.O. Box 980524, Richmond, VA 23298, USA.
| | | | | | | | | | | |
Collapse
|
19
|
Improgo MRD, Scofield MD, Tapper AR, Gardner PD. The nicotinic acetylcholine receptor CHRNA5/A3/B4 gene cluster: dual role in nicotine addiction and lung cancer. Prog Neurobiol 2010; 92:212-26. [PMID: 20685379 DOI: 10.1016/j.pneurobio.2010.05.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 05/15/2010] [Accepted: 05/27/2010] [Indexed: 01/19/2023]
Abstract
More than 1 billion people around the world smoke, with 10 million cigarettes sold every minute. Cigarettes contain thousands of harmful chemicals including the psychoactive compound, nicotine. Nicotine addiction is initiated by the binding of nicotine to nicotinic acetylcholine receptors, ligand-gated cation channels activated by the endogenous neurotransmitter, acetylcholine. These receptors serve as prototypes for all ligand-gated ion channels and have been extensively studied in an attempt to elucidate their role in nicotine addiction. Many of these studies have focused on heteromeric nicotinic acetylcholine receptors containing α4 and β2 subunits and homomeric nicotinic acetylcholine receptors containing the α7 subunit, two of the most abundant subtypes expressed in the brain. Recently however, a series of linkage analyses, candidate-gene analyses and genome-wide association studies have brought attention to three other members of the nicotinic acetylcholine receptor family: the α5, α3 and β4 subunits. The genes encoding these subunits lie in a genomic cluster that contains variants associated with increased risk for several diseases including nicotine dependence and lung cancer. The underlying mechanisms for these associations have not yet been elucidated but decades of research on the nicotinic receptor gene family as well as emerging data provide insight on how these receptors may function in pathological states. Here, we review this body of work, focusing on the clustered nicotinic acetylcholine receptor genes and evaluating their role in nicotine addiction and lung cancer.
Collapse
Affiliation(s)
- Ma Reina D Improgo
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, 303 Belmont Street, Worcester, MA 01604, United States
| | | | | | | |
Collapse
|
20
|
Naumenko VS, Kondaurova EM, Popova NK. Central 5-HT3 receptor-induced hypothermia in mice: Interstrain differences and comparison with hypothermia mediated via 5-HT1A receptor. Neurosci Lett 2009; 465:50-4. [DOI: 10.1016/j.neulet.2009.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 08/27/2009] [Accepted: 09/02/2009] [Indexed: 12/01/2022]
|
21
|
Shiloh R, Weizman A, Stryjer R, Kahan N, Waitman DA. Altered thermoregulation in ambulatory schizophrenia patients: a naturalistic study. World J Biol Psychiatry 2009; 10:163-70. [PMID: 19514098 DOI: 10.1080/15622970701413833] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND Schizophrenia patients may exhibit alterations in core/body temperature. Hence, we intended to examine the potential existence of thermoregulatory abnormalities in ambulatory schizophrenia patients. METHODS Anonymous electronic patient record data of the Leumit Health Fund (Israel) were screened for all schizophrenia patients who have no other apparent chronic co-morbidity (mental or non-mental) and had their oral temperature assessed during routine follow-ups (Schiz-rFUs) or for various transitory infectious/inflammatory processes (Schiz-Infect) during the years 1999-2005 (n = 535). The comparison group consisted of a comparable sample (n = 560) of healthy subjects (Control-rFUs and Control-Infect). RESULTS The sub-group of Schiz-rFUs (n = 216) exhibited significantly lower mean oral temperature compared to the matched group of Control-rFUs (n = 140) (36.72 +/- 0.54 vs. 36.94 +/- 0.64C, respectively; P<0.05). There was no significant difference in mean oral temperatures between the Schiz-Infect (n = 319) and the Control-Infect (n = 420) (37.32 +/- 0.92 vs. 37.28 +/- 0.98C, respectively; NS). CONCLUSIONS Ambulatory schizophrenia patients without a concomitant infectious/inflammatory process exhibit altered thermoregulation manifested by a substantial (about 0.2 C) and significantly lower oral temperature compared to healthy comparison subjects as well as a potential exaggerated increase in oral temperature during transitory infectious/inflammatory processes. The relevance of these phenomena to the pathophysiology of schizophrenia as well as the potential immune-mediated pathologies in schizophrenia merit further investigation.
Collapse
Affiliation(s)
- Roni Shiloh
- Geha Mental Health Center, Felsenstein Medical Research Center, Rabin Medical Center, Beilinson Campus, Petach-Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | | | | | | | | |
Collapse
|
22
|
In vivo effects of 3-iodocytisine: pharmacological and genetic analysis of hypothermia and evaluation of chronic treatment on nicotinic binding sites. Neuropharmacology 2009; 57:332-42. [PMID: 19481555 DOI: 10.1016/j.neuropharm.2009.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 05/14/2009] [Accepted: 05/19/2009] [Indexed: 11/23/2022]
Abstract
Several cytisine derivatives have been developed in the search for more selective drugs at nicotinic acetylcholine receptors (nAChR). Binding experiments in transfected cell lines showed that the iodination of cytisine in the position 3 of the pyridone ring increased potency at alpha7-nAChR and to a lesser extent at the alpha4beta2 subtypes, both of which are widely expressed in the brain. However, no in vivo studies have been published on this compound. Inhibition curves presented here using wild type, beta2, and beta4-null mutant mice confirm that 3-IC binds to alpha4beta2 *, alpha7 * and alpha3beta4 * receptors with higher affinity than cytisine (asterisk indicates the receptor may contain additional subunits, Lukas et al., 1999). Intraperitoneal injection of 3-iodocytisine (3-IC) induced considerable dose-dependent hypothermia in DBA/2J and C57BL/6J mice. This response was blocked by mecamylamine and partially inhibited by hexamethonium. beta4-null mice displayed significantly less 3-IC-induced hypothermia than wild-type mice, beta2-null mice were somewhat less affected than wild types, while responses of alpha7 *-null mice were similar to wild types. Mice treated chronically with 3-IC display a marked increase in alpha7 * and alpha4beta2 * binding sites determined by radioligand binding in membrane preparations from cerebral cortex and hippocampus. Quantitative autoradiographic analysis of 28 brain regions of mice treated with 3-IC was consistent with the membrane binding, detecting an increase of cytisine-sensitive [(125)I]epibatidine binding sites, while cytisine-resistant [(125)I]epibatidine sites were unchanged. [(125)I]alpha-Bungarotoxin binding sites also exhibited up-regulation. These results give a first evaluation of in vivo consequences of 3-IC as a potent agonist with marked effects on mice.
Collapse
|
23
|
Fowler CD, Arends MA, Kenny PJ. Subtypes of nicotinic acetylcholine receptors in nicotine reward, dependence, and withdrawal: evidence from genetically modified mice. Behav Pharmacol 2008; 19:461-84. [PMID: 18690103 PMCID: PMC2669417 DOI: 10.1097/fbp.0b013e32830c360e] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) can regulate the activity of many neurotransmitter pathways throughout the central nervous system and are considered to be important modulators of cognition and emotion. nAChRs are also the primary site of action in the brain for nicotine, the major addictive component of tobacco smoke. nAChRs consist of five membrane-spanning subunits (alpha and beta isoforms) that can associate in various combinations to form functional nAChR ion channels. Owing to a dearth of nAChR subtype-selective ligands, the precise subunit composition of the nAChRs that regulate the rewarding effects of nicotine and the development of nicotine dependence are unknown. The advent of mice with genetic nAChR subunit modifications, however, has provided a useful experimental approach to assess the contribution of individual subunits in vivo. Here, we review data generated from nAChR subunit knockout and genetically modified mice supporting a role for discrete nAChR subunits in nicotine reinforcement and dependence processes. Importantly, the rates of tobacco dependence are far higher in patients suffering from comorbid psychiatric illnesses compared with the general population, which may at least partly reflect disease-associated alterations in nAChR signaling. An understanding of the role of nAChRs in psychiatric disorders associated with high rates of tobacco addiction, therefore, may reveal novel insights into mechanisms of nicotine dependence. Thus, we also briefly review data generated from genetically modified mice to support a role for discrete nAChR subunits in anxiety disorders, depression, and schizophrenia.
Collapse
Affiliation(s)
- Christie D. Fowler
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Michael A. Arends
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Paul J. Kenny
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| |
Collapse
|
24
|
Steiner AA, Oliveira DL, Roberts JL, Petersen SR, Romanovsky AA. Nicotine administration and withdrawal affect survival in systemic inflammation models. J Appl Physiol (1985) 2008; 105:1028-34. [PMID: 18617624 DOI: 10.1152/japplphysiol.90619.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
How different regimens of nicotine administration and withdrawal affect systemic inflammation is largely unknown. We studied the effects of chronic and acute nicotine administration and of nicotine withdrawal on the outcome of aseptic and septic systemic inflammation. Male C57BL/6 mice were implanted with subcutaneous osmotic pumps (to deliver nicotine) and intrabrain telemetry probes (to measure temperature). Aseptic inflammation was induced by lipopolysaccharide (40 mg/kg ip); sepsis was induced by cecal ligation and puncture. The chronic nicotine administration group received nicotine (28 mg.kg(-1).day(-1)) for 2 wk before the induction of inflammation and continued receiving nicotine until the end of the experiment; the acute nicotine administration group received saline for 2 wk and nicotine thereafter; the nicotine withdrawal group received nicotine for 2 wk and saline thereafter; and the no-nicotine group was infused with saline throughout the experiment. Compared with no nicotine, the chronic nicotine administration did not affect survival in either model of inflammation, possibly due to the development of nicotine tolerance. The acute nicotine administration increased the survival rate in aseptic inflammation from 11 to 33% (possibly by suppressing inflammation) but worsened the outcome of sepsis (possibly because the suppression of inflammation promoted microbial proliferation). Oppositely to acute nicotine, nicotine withdrawal increased the survival rate in sepsis from 18 to 40%. The effects on survival were not due to changes in body temperature. We conclude that acute nicotine administration and nicotine withdrawal affect survival in systemic inflammation and that these effects strongly depend on whether inflammation is aseptic or septic.
Collapse
Affiliation(s)
- Alexandre A Steiner
- Systemic Inflammation Laboratory, Trauma Research, St. Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, USA
| | | | | | | | | |
Collapse
|
25
|
Portugal GS, Gould TJ. Genetic variability in nicotinic acetylcholine receptors and nicotine addiction: converging evidence from human and animal research. Behav Brain Res 2008; 193:1-16. [PMID: 18571741 DOI: 10.1016/j.bbr.2008.05.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 05/08/2008] [Accepted: 05/10/2008] [Indexed: 12/13/2022]
Abstract
Tobacco smoking is a leading preventable cause of death in the United States and produces a major health and economic burden. Although the majority of smokers want to quit, few are successful. These data highlight the need for additional research into the neurobiology of tobacco dependence. Addiction to nicotine, the main psychoactive component of tobacco, is influenced by multiple factors that include individual differences in genetic makeup. Twin studies have demonstrated that genetic factors can influence vulnerability to nicotine addiction, and subsequent research has identified genes that may alter sensitivity to nicotine. In humans, genome-wide and candidate gene association studies have demonstrated that genes encoding nicotinic acetylcholine receptor (nAChR) proteins are associated with multiple smoking phenotypes. Similarly, research in mice has provided evidence that naturally occurring variability in nAChR genes is associated with changes in nicotine sensitivity. Furthermore, the use of genetic knockout mice has allowed researchers to determine the nAChR genes that mediate the effects of nicotine, whereas research with knockin mice has demonstrated that changes to nAChR genes can dramatically alter nicotine sensitivity. This review will examine the genetic factors that alter susceptibility to nicotine addiction, with an emphasis on the genes that encode nAChR proteins.
Collapse
Affiliation(s)
- George S Portugal
- Department of Psychology, Weiss Hall, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
| | | |
Collapse
|
26
|
Kedmi M, Orr-Urtreger A. Differential brain transcriptome of beta4 nAChR subunit-deficient mice: is it the effect of the null mutation or the background strain? Physiol Genomics 2006; 28:213-22. [PMID: 16985005 DOI: 10.1152/physiolgenomics.00155.2006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Studies using mice with beta4 nicotinic acetylcholine receptor (nAChR) subunit deficiency (beta4-/- mice) helped reveal the roles of this subunit in bradycardiac response to vagal stimulation, nicotine-induced seizure activity and anxiety. To identify genes that might be related to beta4-containing nAChRs activity, we compared the mRNA expression profiles of brains from beta4-/- and wild-type mice using Affymetrix U74Av2 microarray. Seventy-seven genes significantly differentiated between these two experimental groups. Of them, the two most downregulated were spastic paraplegia 21 (human) homolog (Spg21) and 6-pyruvoyl-tetrahydropterin synthase (Pts) genes. Since the targeted mutagenesis of the beta4 nAChR subunit was done by using two mouse strains, 129SvEv and C57BL/6J, it is possible that the genes closely linked to the mutated beta4 gene represent the 129SvEv allele and not the control C57BL/6J-driven allele. We examined this possibility by using public database and quantitative RT-PCR. The expression levels of Spg21 and Pts genes that, like the beta4 gene, are localized on mouse chromosome 9, as well as the expression levels of other genes located on this chromosome, were dependent on the mouse background strain. The 67 differentially expressed genes that are not located on chromosome 9 were further analyzed for overrepresented functional annotations and transcription regulatory elements compared with the entire microarray. Genes encoding for proteins involved in tyrosine phosphatase activity, calcium ion binding, cell growth and/or maintenance, and chromosome organization were overrepresented. Our data enhance the understanding of the molecular interactions involved in the beta4 nAChR subunit function. They also emphasize the need for careful interpretation of expression microarray studies done on genetically manipulated animals.
Collapse
Affiliation(s)
- Merav Kedmi
- Genetic Institute, Tel Aviv Sourasky Medical Center, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | |
Collapse
|