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Amer AE, El-Sheakh AR, Hamed MF, El-Kashef HA, Nader MA, Shehatou GSG. Febuxostat attenuates vascular calcification induced by vitamin D3 plus nicotine in rats. Eur J Pharm Sci 2020; 156:105580. [PMID: 33010420 DOI: 10.1016/j.ejps.2020.105580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 09/26/2020] [Accepted: 09/27/2020] [Indexed: 11/30/2022]
Abstract
This study was undertaken to investigate the possible ameliorative influences of febuxostat (FEB) on vitamin D3 plus nicotine (VDN)-induced vascular calcification (VC) in Wistar rats. VDN rats received a single dose of vitamin D3 (300.000 IU/kg, I.M) and two oral doses of nicotine (25 mg/kg) on day 1. They were then administrated FEB, in two doses (10 and 15 mg/kg/day, orally), or the drug vehicle, for 4 weeks. Age-matched normal rats served as control. At the end of the experiment, body weight, kidney function parameters, serum ionic composition, cardiovascular measures, aortic calcium deposition and aortic levels of oxidative stress markers, interleukin 1β (IL-1β), runt-related transcription factor 2 (Runx2) and osteopontin (OPN) were determined. Aortic immunoexpressions of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), matrix metalloproteinase-9 (MMP-9) and α-smooth muscle actin (α-SMA) were evaluated. FEB significantly restored body weight loss, ameliorated kidney function and diminished serum disturbances of calcium and phosphorus in VDN rats. Moreover, FEB reduced VDN-induced elevations in aortic calcium deposition, SBP and DBP. FEB (15 mg/kg) markedly decreased left ventricular hypertrophy and bradycardia in VDN group. Mechanistically, FEB dose-dependently improved oxidative damage, decreased levels of IL-1β and Runx2, lessened expression of TNF-α, iNOS and MMP-9 and enhanced expression of OPN and α-SMA in VDN aortas relative to controls. These findings indicate that FEB, mainly at the higher administered dose (15 mg/kg), successfully attenuated VDN-induced VC. FEB may be useful in reducing VC in patients at high risk, including those with chronic kidney disease and diabetes mellitus.
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Affiliation(s)
- Ahmed E Amer
- Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Delta University for Science and Technology, International Coastal Road, Gamasa City, Dakahliya, Egypt; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Dakahliya, Egypt
| | - Ahmed R El-Sheakh
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Dakahliya, Egypt
| | - Mohamed F Hamed
- Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Dakahliya, Egypt
| | - Hassan A El-Kashef
- Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Delta University for Science and Technology, International Coastal Road, Gamasa City, Dakahliya, Egypt; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Dakahliya, Egypt
| | - Manar A Nader
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Dakahliya, Egypt
| | - George S G Shehatou
- Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Delta University for Science and Technology, International Coastal Road, Gamasa City, Dakahliya, Egypt; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Dakahliya, Egypt.
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Mechanisms involved in nicotinic acetylcholine receptor-induced neurotransmitter release from sympathetic nerve terminals in the mouse vas deferens. PLoS One 2011; 6:e29209. [PMID: 22216213 PMCID: PMC3245264 DOI: 10.1371/journal.pone.0029209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 11/22/2011] [Indexed: 01/12/2023] Open
Abstract
Prejunctional nicotinic acetylcholine receptors (nAChRs) amplify postganglionic sympathetic neurotransmission, and there are indications that intraterminal Ca2+ stores might be involved. However, the mechanisms by which nAChR activation stimulates neurotransmitter release at such junctions is unknown. Rapid local delivery (picospritzing) of the nAChR agonist epibatidine was combined with intracellular sharp microelectrode recording to monitor spontaneous and field-stimulation-evoked neurotransmitter release from sympathetic nerve terminals in the mouse isolated vas deferens. Locally applied epibatidine (1 µM) produced ‘epibatidine-induced depolarisations’ (EIDs) that were similar in shape to spontaneous excitatory junction potentials (SEJPs) and were abolished by nonselective nAChR antagonists and the purinergic desensitizing agonist α,β-methylene ATP. The amplitude distribution of EIDs was only slightly shifted towards lower amplitudes by the selective α7 nAChR antagonists α-bungarotoxin and methyllcaconitine, the voltage-gated Na+ channel blocker tetrodotoxin or by blocking voltage-gated Ca2+ channels with Cd2+. Lowering the extracellular Ca2+ concentration reduced the frequency of EIDs by 69%, but more surprisingly, the Ca2+-induced Ca2+ release blocker ryanodine greatly decreased the amplitude (by 41%) and the frequency of EIDs by 36%. Ryanodine had no effect on electrically-evoked neurotransmitter release, paired-pulse facilitation, SEJP frequency, SEJP amplitude or SEJP amplitude distribution. These results show that activation of non-α7 nAChRs on sympathetic postganglionic nerve terminals induces high-amplitude junctional potentials that are argued to represent multipacketed neurotransmitter release synchronized by intraterminal Ca2+-induced Ca2+ release, triggered by Ca2+ influx directly through the nAChR. This nAChR-induced neurotransmitter release can be targeted pharmacologically without affecting spontaneous or electrically-evoked neurotransmitter release.
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Schmidt R, Weidner C, Schmelz M. Time course of acetylcholine-induced activation of sympathetic efferents matches axon reflex sweating in humans. J Peripher Nerv Syst 2011; 16:30-6. [DOI: 10.1111/j.1529-8027.2011.00320.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ozturk Fincan GS, Vural IM, Ercan ZS, Sarioglu Y. Enhancement effects of nicotine on neurogenic relaxation responses in the corpus cavernosum in rabbits: The role of nicotinic acetylcholine receptor subtypes. Eur J Pharmacol 2010; 627:281-4. [DOI: 10.1016/j.ejphar.2009.10.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2009] [Revised: 09/26/2009] [Accepted: 10/14/2009] [Indexed: 11/30/2022]
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5
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Vural IM, Ozturk Fincan GS, Burul Bozkurt N, Ercan ZS, Sarioglu Y. Role of nicotinic acetylcholine receptor subtypes on nicotine-induced neurogenic contractile response alternation in the rabbit gastric fundus. Eur J Pharmacol 2009; 602:395-8. [DOI: 10.1016/j.ejphar.2008.11.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 10/30/2008] [Accepted: 11/17/2008] [Indexed: 11/28/2022]
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6
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Hydrogen peroxide and antioxidizing enzymes involved in modulation of transient facilitatory effects of nicotine on neurogenic contractile responses in rat gastric fundus. Eur J Pharmacol 2008; 587:267-72. [DOI: 10.1016/j.ejphar.2008.03.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 03/03/2008] [Accepted: 03/14/2008] [Indexed: 11/22/2022]
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7
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Giacomin E, Palmerini E, Ballo P, Zacà V, Bova G, Mondillo S. Acute effects of caffeine and cigarette smoking on ventricular long-axis function in healthy subjects. Cardiovasc Ultrasound 2008; 6:9. [PMID: 18318902 PMCID: PMC2288591 DOI: 10.1186/1476-7120-6-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2007] [Accepted: 03/04/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Few data exist regarding the direct effects of caffeine and smoking on cardiac function. We sought to explore the acute effects of caffeine assumption, cigarette smoking, or both on left ventricular (LV) and right ventricular (RV) function in a population of young normal subjects. METHODS Forty-five healthy subjects aged 25 +/- 2 years underwent echocardiography. Fifteen of them were non-smokers and habitual coffee consumers (group 1), 15 were smokers and not habitual coffee consumers (group 2), and 15 were smokers and habitual coffee consumers (group 3). Peak systolic (Sa), early diastolic Ea, and late diastolic (Aa) velocity of mitral annulus were measured by pulsed Tissue Doppler, and left atrioventricular plane displacement was determined by M-mode. Tricuspid annular velocities and systolic excursion (TAPSE) were also determined. Measurements were performed at baseline and after oral assumption of caffeine 100 mg in group 1, one cigarette smoking in group 2, and both in group 3. RESULTS No changes in ventricular function were observed in group 1 after caffeine administration. In group 2, cigarette smoking yielded an acute increase in mitral Aa (+12.1%, p = 0.0026), tricuspid Sa (+9.8%, p = 0.012) and TAPSE (+7.9%, p = 0.017), and a decrease in the mitral Ea/Aa ratio (-8.5%, p = 0.0084). Sequential caffeine assumption and cigarette smoking in group 3 was associated with an acute increase in mitral Aa (+13.0%, p = 0.015) and tricuspid Aa (+11.6%, p < 0.0001) and a reduction in mitral Ea/Aa ratio (-8.5%, p = 0.0084) tricuspid Ea (-6.6%, p = 0.048) and tricuspid Ea/Aa ratio (-9.6%, p = 0.0003). In a two-way ANOVA model controlling for hemodynamic confounding factors, changes in the overall population remained significant for mitral Aa and Ea/Aa ratio, and for tricuspid Aa and Ea/Aa ratio. CONCLUSION In young healthy subjects, one cigarette smoking is associated to an acute impairment in LV diastolic function and a hyperdynamic RV systolic response. Caffeine assumption alone does not exert any acute effect on ventricular long-axis function, but potentiates the negative effect of cigarette smoking by abolishing RV supernormal response and leading to a simultaneous impairment in both LV and RV diastolic function.
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Affiliation(s)
- Elisa Giacomin
- Department of Cardiovascular Disease, University of Siena, Italy
| | | | - Piercarlo Ballo
- Cardiology Operative Unit, S. Andrea Hospital, La Spezia, Italy
| | - Valerio Zacà
- Department of Cardiovascular Disease, University of Siena, Italy
| | - Giovanni Bova
- Department of Cardiovascular Disease, University of Siena, Italy
| | - Sergio Mondillo
- Department of Cardiovascular Disease, University of Siena, Italy
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8
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Ilhan SO, Vural IM, Dileköz E, Oztürk GS, Sarioglu Y. Enhancement effects of nicotine on neurogenic contractile responses in rabbit gastric fundus. Eur J Pharmacol 2007; 561:182-8. [PMID: 17292347 DOI: 10.1016/j.ejphar.2006.12.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 12/15/2006] [Accepted: 12/21/2006] [Indexed: 10/23/2022]
Abstract
Nicotine, a nicotinic acetylcholine receptor agonist, plays a role in the modulation of neurotransmitter release following nerve stimulation in both the central and the peripheral nervous system. Nitric oxide and prostaglandins modulate the release of various neurotransmitters in different tissues. We aimed to investigate the effects of nicotine on neurogenic contractile responses via nicotinic acetylcholine receptors and, if a change occurred, to investigate the effects of N(W)-nitro-L-arginine methyl ester (L-NAME) and indomethacin on this change in rabbit gastric fundus. Electrical field stimulation (EFS)-evoked contractile responses were recorded from gastric fundus strips obtained from rabbits with an isometric force displacement transducer. Nicotine was applied to preparations at varying concentrations. Then, the effects of hexamethonium, cadmium (Cd(2+)), indomethacin, and L-NAME were tested on the EFS-evoked contractions in the presence of nicotine. Nicotine-induced transient neurogenic contractions in a dose-dependent manner. Cd(2+) and hexamethonium inhibited nicotine-induced transient neurogenic contractions, but indomethacin and L-NAME produced no effect. In conclusion, nicotine increased EFS-evoked contractile responses, possibly by facilitating neurotransmitter release from nerve terminals by a mechanism dependent on the influx of Ca(2+) from voltage-gated Ca(2+) channels via activation of nicotinic acetylcholine receptors in isolated rabbit gastric fundus. Endogenous nitric oxide and prostaglandins do not play a physiological role in the regulation of this neurotransmitter release.
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Affiliation(s)
- Sevil Ozger Ilhan
- Refik Saydam Hygiene Center Presidency, School of Public Health, Ankara, Turkey
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9
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Vural IM, Ozturk GS, Ercan ZS, Sarioglu Y. Nicotine potentiates the neurogenic contractile response of rabbit bladder tissue via nicotinic acetylcholine receptors: Nitric oxide and prostaglandins have no role in this process. Life Sci 2007; 80:1123-7. [PMID: 17229444 DOI: 10.1016/j.lfs.2006.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 11/24/2006] [Accepted: 12/01/2006] [Indexed: 10/23/2022]
Abstract
Nicotine, a nicotinic acetylcholine receptors (nAChRs) agonist, has a role in modulation of the neurotransmitter release following nerve stimulation in both the central and peripheral nervous systems. The aim of this study was to determine whether electrical field stimulation (EFS)-evoked contractions are altered in rabbit bladder in the presence of nicotine and, if an alteration occurs, to investigate the effects of nitric oxide and prostaglandins on nicotine-induced alternation in isolated rabbit bladder. EFS-evoked contractile responses from rabbit bladder obtained were recorded with isometric force displacement transducers. Nicotine was added to preparations at various concentrations. The effects of hexamethonium, cadmium (Cd(2+)), indomethacin and N-nitro-L-arginine methyl ester (L-NAME) were tested on the EFS-evoked contractions in the presence of nicotine. Nicotine led to a dose-dependent increase in the amplitude of the EFS-evoked contractile responses. Cd(2+) and hexamethonium inhibited the nicotine-induced increase in EFS-evoked responses, whereas indomethacin and L-NAME had no effect. In conclusion, nicotine increased the EFS-evoked contractile responses possibly by facilitating release of neurotransmitters from nerve terminals by a mechanism dependent on the influx of Ca(2+) from voltage-gated Ca(2+) channels (VGCCs) via activation of nAChRs in isolated rabbit bladder. Nitric oxide and prostaglandins do not have a physiological role in the regulation of neurotransmitter release.
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Affiliation(s)
- Ismail Mert Vural
- Department of Pharmacology, Medical School, Gazi University, 06510 Besevler Ankara, Turkey.
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10
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Nas T, Barun S, Oztürk GS, Vural IM, Ercan ZS, Sarioğlu Y. Nicotine Potentiates the Electrical Field Stimulation-Evoked Contraction of Non-Pregnant Rabbit Myometrium. TOHOKU J EXP MED 2007; 211:187-93. [PMID: 17287603 DOI: 10.1620/tjem.211.187] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The women who smoke have lower fertility rates which might be due to harmful effects of nicotine on tubal function and menstrual cycle. Although the uterine contractility of the non-pregnant uterus plays an important role in the human reproduction process, the influence of nicotine on the contractile responses in uterus is not known. Nicotine increases the release of neurotransmitters following nerve stimulation both in the central and peripheral nervous system through acting on nicotinic acetylcholine receptors (nAchRs). The aim of this study was to examine whether the electrical field stimulation (EFS)-evoked contraction is altered in rabbit myometrium strips in the presence of nicotine to evaluate the changes in contractility. EFS-evoked contractile responses were recorded from myometrium strips obtained from non-pregnant rabbits in the absence and presence of nicotine. Nicotine led to the increase in the amplitudes of the EFS-evoked contractile responses in a dose-dependent manner. Therefore, the effects of hexamethonium, cadmium, indomethacin, atropine, and N(omega)-Nitro-L-arginine methyl ester hydrochloride were tested on the EFS-evoked contractions in the absence or presence of nicotine to clarify the mechanisms of nicotine-induced potentiation in EFS-evoked contractile responses. Indomethacin, a non-selective cyclooxygenase inhibitor, and hexamethonium, a ganglionic blocker, inhibited nicotine-induced increase in EFS-evoked responses, whereas other chemicals produced no effect. These results suggest that nicotine-induced potentiation may be mediated by nAchRs and prostaglandins. In conclusion, failure of quiescence in the uterus due to increased contractility by nicotine might be one of the factors contributing to infertility in female smokers.
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Affiliation(s)
- Tuncay Nas
- Department of Obstetrics and Gynecology, Medical School, Gazi University, Ankara, Turkey.
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11
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Najem B, Houssière A, Pathak A, Janssen C, Lemogoum D, Xhaët O, Cuylits N, van de Borne P. Acute Cardiovascular and Sympathetic Effects of Nicotine Replacement Therapy. Hypertension 2006; 47:1162-7. [PMID: 16651463 DOI: 10.1161/01.hyp.0000219284.47970.34] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Sympathetic overactivity is implicated in the increased cardiovascular risk of cigarette smokers. Excitatory nicotinic receptors are present on peripheral chemoreceptor cells. Chemoreceptors located in the carotid and aortic bodies increase ventilation (Ve), blood pressure (BP), heart rate (HR), and sympathetic nerve activity to muscle circulation (MSNA) in response to hypoxia. We tested the hypothesis that nicotine replacement therapy (NRT) increases MSNA and chemoreceptor sensitivity to hypoxia. Sixteen young healthy smokers were included in the study (8 women). After a randomized and blinded sublingual administration of a 4-mg tablet of nicotine or placebo, we measured minute Ve, HR, mean BP, and MSNA during normoxia and 5 minutes of isocapnic hypoxia. Maximal voluntary end-expiratory apneas were performed at baseline and at the end of the fifth minute of hypoxia. Nicotine increased HR by 7±3 bpm, mean BP by 5±2 mm Hg, and MSNA by 4±1 bursts/min, whereas subjects breathed room air (all
P
<0.05). During hypoxia, nicotine also raised HR by 8±2 bpm, mean BP by 2±1 mm Hg, and MSNA by 7±2 bursts/min (all
P
<0.05). Nicotine increased MSNA during the apneas performed in normoxia and hypoxia (
P
<0.05). Nicotine also raised the product of systolic BP and HR, a marker of cardiac oxygen consumption, during normoxia, hypoxia, and the apneas (
P
<0.05). Ve, apnea duration, and O
2
saturation during hypoxia and the apneas remained unaffected. In conclusion, sympathoexcitatory effects of NRT are not because of an increased chemoreflex sensitivity to hypoxia. NRT increases myocardial oxygen consumption in periods of reduced oxygen availability.
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Affiliation(s)
- Boutaïna Najem
- Department of Cardiology, Erasme Hospital, Brussels, Belgium,
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12
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Jackson VM, Trout SJ, Cunnane TC. Regional variation in electrically-evoked contractions of rabbit isolated pulmonary artery. Br J Pharmacol 2002; 137:488-96. [PMID: 12359630 PMCID: PMC1573507 DOI: 10.1038/sj.bjp.0704863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2002] [Accepted: 06/27/2002] [Indexed: 11/10/2022] Open
Abstract
1. Electrically-evoked contractions in different regions of the rabbit isolated pulmonary artery have been investigated using stimulation parameters generally assumed to stimulate nerves selectively. 2. In extrapulmonary artery, trains of stimuli (10 Hz; pulse width 0.1 ms) evoked monophasic contractions. In contrast, a biphasic contraction was evoked in the intrapulmonary artery consisting of an initial fast component followed by a secondary very long-lasting component. 3. The contraction in the extrapulmonary artery was prazosin-sensitive (1 micro M) whereas that in the intrapulmonary artery was prazosin-resistant. 4. alpha,beta-Methylene ATP (1 micro M), atropine (1 micro M), losartan (1 micro M), BIBO3304 (1 nM) or nifedipine (1 micro M) had no effect on the biphasic contraction of the intrapulmonary artery. Bretylium (2 micro M) abolished the contraction of extrapulmonary artery but only partially inhibited the initial component in the intra region with no effect on the second component. 5. Tetrodotoxin (0.3-1 micro M), abolished the contraction of extrapulmonary artery but only partially reduced the electrically-evoked contraction of intrapulmonary artery. 6. Removal of the endothelium and application of sulphisoxazole (0.6-22 micro M) had no effect. 7. Varying the resting tone on the arteries, or applying gadolinium, had no effect on contractions. 8. Using confocal microscopy and calcium imaging, reproducible whole cell calcium transients were evoked in individual smooth muscle cells in intact preparations but only when direct muscle stimulation was used (pulse width of 5-10 ms). No detectable changes in calcium were elicited when brief pulse widths were used (0.1-2 ms). 9. Together, these data suggest that noradrenaline is the neurotransmitter inducing contraction in extrapulmonary artery. Noradrenaline and sympathetic nerves appear to play a less important role in the intrapulmonary artery. The tetrodoxin-resistant component is not mediated by ATP, NPY, acetylcholine, angiotensins, ET-1, stretch-activation or Ca(2+) influx through L-type Ca(2+) channels. Smooth muscle cells do not appear to be damaged by the stimulation protocol. The mechanism underlying the long lasting contraction of intrapulmonary artery evoked by brief electrical stimuli remains to be elucidated.
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Affiliation(s)
- V Margaret Jackson
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, U.K
| | - Stephen J Trout
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, U.K
| | - Tom C Cunnane
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, U.K
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13
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Brain KL, Trout SJ, Jackson VM, Dass N, Cunnane TC. Nicotine induces calcium spikes in single nerve terminal varicosities: a role for intracellular calcium stores. Neuroscience 2002; 106:395-403. [PMID: 11566509 DOI: 10.1016/s0306-4522(01)00280-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While nicotine is known to act at neuronal nicotinic acetylcholine receptors (nAChRs) to facilitate neurotransmitter release, the mechanisms underlying this action are poorly understood. Some of its effects are known to be mediated by presynaptic receptors. In the mouse vas deferens nicotine (10-30 microM) transiently increased the force of neurogenic contraction by 135+/-25%, increased the amplitude of excitatory junction potentials by 74+/-6% and increased the frequency of spontaneous excitatory junction potentials in four out of six preparations. Confocal microscopy and the calcium indicator Oregon Green 488 BAPTA-1 dextran were used to measure calcium concentration changes in the nerve terminals. Nicotine did not affect the action potential-evoked calcium transient but instead triggered small, random fluctuations ("calcium spikes") in intra-varicosity calcium concentrations at an average frequency of 0.09+/-0.02 Hz. These were insensitive to tetrodotoxin at a concentration that blocked action-potential evoked calcium transients (300 nM). They were abolished by the nAChR blocker hexamethonium (100 microM) and by both ryanodine (100 microM) and caffeine (3 mM), agents that modify calcium release from intracellular stores. We propose a novel mechanism whereby nicotine's action at nAChRs triggers calcium-induced calcium release from a ryanodine-sensitive calcium store in nerve terminals. This primes neurotransmitter release mechanisms and enhances both spontaneous and action potential-evoked neurotransmitter release.
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Affiliation(s)
- K L Brain
- Department of Pharmacology, Mansfield Road, University of Oxford, Oxford OX1 3QT, UK
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14
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Zubieta J, Lombardi U, Minoshima S, Guthrie S, Ni L, Ohl LE, Koeppe RA, Domino EF. Regional cerebral blood flow effects of nicotine in overnight abstinent smokers. Biol Psychiatry 2001; 49:906-13. [PMID: 11377408 DOI: 10.1016/s0006-3223(00)01070-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Most people agree that dependence to tobacco is mediated by the effects of nicotine on the central nervous system, albeit the neural pathways involved are not clearly delineated. We investigated the effect of nasal nicotine spray on regional cerebral blood flow (rCBF) in a sample of habitual smokers, with H2 15O and positron emission tomography (PET). METHODS Eighteen volunteer smokers were studied after 12 hours of smoking deprivation. Regional cerebral blood flow measures were obtained with PET and 50 mCi H2 15O in six consecutive scans. Nicotine spray and a placebo spray were administered in a single-blind design, preceded and followed by baseline studies. Images were coregistered and anatomically standardized. Square (9-mm side) regions of interest were placed in 10 preselected brain regions, bilaterally. The effects of the experimental condition and gender were tested with two-way repeated-measures analysis of variance in each of the regions studied. RESULTS Nicotine reduced rCBF in the left anterior temporal cortex and in the right amygdala. Increases were noted in the right anterior thalamus. CONCLUSIONS In habitual smokers after overnight abstinence, nicotine induced differing effects on regional blood flow relative to whole brain blood flow. Increases were observed in the thalamus, a region rich in nicotinic receptors, and reductions in limbic and paralimbic (amygdala, anterior temporal cortex) regions.
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Affiliation(s)
- J Zubieta
- Department of Psychiatry, The University of Michigan, (J-KZ, SG), Ann Arbor, Michigan 48104-1687, USA
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15
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Schmelz M, Schmidt R, Bickel A, Torebjörk HE, Handwerker HO. Innervation territories of single sympathetic C fibers in human skin. J Neurophysiol 1998; 79:1653-60. [PMID: 9535936 DOI: 10.1152/jn.1998.79.4.1653] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Microneurography techniques were used to record action potentials from unmyelinated nerve fibers (C fibers) in the cutaneous fascicles of the peroneal nerve in healthy volunteers. C units were identified by their long latency responses to electrical stimulation of their terminals in the skin. Their responsiveness to mechanical or heat stimuli applied to the skin or to sympathetic reflex provocation tests was determined by transient slowing of conduction velocity following activation (marking technique). In a sample of 381 C units, 59 were unresponsive to mechanical and thermal stimulation of their endings, but responded to sympathetic reflex provocation tests, e.g., arousal or deep inspiration. They were classified as sympathetic efferent units. On average, conduction velocities of sympathetic units were lower (0.78 +/- 0.12 m/s, mean +/- SD) than those of mechano-heat (CMH) or mechanoresponsive (CM) afferent C units (0.91 +/- 0.14 m/s). Endings of most of the sympathetic units were located in the skin of toes or in the foot dorsum. Innervation territories of 16 sympathetic units were mapped by means of conditioning transcutaneous electrical stimuli. Twelve units had one continuous skin territory, whereas two units had two and two other units had three and five separate territories, respectively. The mean innervated area was 128 mm2 (range: 24-350 mm2). Innervation territories of sympathetic units were of approximately the same size in different skin regions on the lower leg, foot, or toes. Based on responses to whole body cooling and warming, two units were tentatively classified as vasoconstrictor and sudomotor units, respectively. Eleven units were tested for responsiveness to iontophoresis of acetylcholine in their innervation territories. In five of them, activity was induced that was not due to central reflex activity but instead due to antidromic activation from the peripheral terminals. Iontophoresis of saline or histamine was ineffective. These findings confirm the existence of excitatory cholinergic receptors in the terminal membrane of some sympathetic units, possibly sudomotors.
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Affiliation(s)
- M Schmelz
- Department of Physiology I, University of Erlangen/Nürnberg, D-91054 Erlangen, Germany
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Shimosawa T, Ito Y, Ando K, Kitamura K, Kangawa K, Fujita T. Proadrenomedullin NH(2)-terminal 20 peptide, a new product of the adrenomedullin gene, inhibits norepinephrine overflow from nerve endings. J Clin Invest 1995; 96:1672-6. [PMID: 7657838 PMCID: PMC185795 DOI: 10.1172/jci118208] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Proadrenomedullin NH(2)-terminal 20 peptide (PAMP) and adrenomedullin, which are derived from proadrenomedullin, exhibit remarkable hypotensive action. We investigated the effect of PAMP and adrenomedullin on peripheral sympathetic neutral transmission. Using perfused rat mesenteric arteries, PAMP (0, 1, 5, and 10 pmol/ml) decreased norepinephrine overflow by periarterial electrical nerve stimulation in a dose-dependent fashion (0.244 +/- 0.043, 0.231 +/- 0.048, 0.195 +/- 0.061 and 0.168 +/- 0.051 ng/gram tissue weigh: NS, P < 0.05, and P < 0.02, respectively). In contrast to PAMP, adrenomedullin (1, 5, and 10 pmol/ml) did not change it. In contrast, vasoconstrictive response of mesenteric arteries to exogenous norepinephrine was significantly attenuated by 10 pmol/ml of adrenomedullin but not by the same dose of PAMP. Calcitonin gene-related peptide (8-37) [CGRP(8-37)], a CGRP receptor antagonist, inhibited the vasodilatory effect of adrenomedullin but could not suppress the sympathoinhibitory effect of PAMP. Neither a nicotinic antagonist, hexamethonium, nor a presynaptic alfa2 antagonist, yohimbine, blocked the sympathoinhibitory effect of PAMP. Thus, it suggests that PAMP and adrenomedullin, which are derived from the same gene, exhibit different hypotensive mechanisms: PAMP inhibits neural transmission at peripheral sympathetic nerve ending, although adrenomedullin directly dilates vascular smooth muscle, possibly through CGRP-like receptor.
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Affiliation(s)
- T Shimosawa
- Fourth Department of Internal Medicine, University of Tokyo School of Medicine, Japan
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Abstract
PURPOSE It has been reported that tobacco smoking temporarily affects postural stability We have examined whether smoking habits have a long-term effect on the body balance control using computer-aided posturography. SUBJECTS AND METHODS The postural stability of 80 male forest workers was measured with a force platform technique with eyes closed. Average body sway velocity (ASV [mm/s]) was determined and used as a stability index. Detailed interviews on tobacco smoking and otologic examinations were carried out. Smoking habits were classified into five categories: nonsmokers (53.8%), ex-smokers (17.5%) and current smokers, comprising light (3.8%), moderate (15%), and heavy (10%) smokers. RESULTS The smoking habits of the subjects correlated significantly with ASV, but hours of the exposure to noise and hand-arm vibration from chain saws did not. The correlation of the smoking habits remained significant even after eliminating the effect of age and exposure by partialization. Age in itself had no effect on ASV but interacted with smoking to increase ASV. The group means of ASV increased with the increase in smoking. Significant differences in ASV were found in the moderate and heavy smokers compared with the nonsmokers. CONCLUSION Smokers exhibited more unstable posturographic results than nonsmokers. Smoking habits were suggested to have a long-term effect on the posture control system.
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Affiliation(s)
- M Iki
- Department of Environmental Health, Fukui Medical School, Japan
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Affiliation(s)
- N L Benowitz
- Clinical Pharmacology Unit, San Francisco General Hospital Medical Center, CA
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Dinger B, Gonzalez C, Yoshizaki K, Fidone S. Localization and function of cat carotid body nicotinic receptors. Brain Res 1985; 339:295-304. [PMID: 4027628 DOI: 10.1016/0006-8993(85)90095-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Acetylcholine and nicotinic agents excite cat carotid body chemoreceptors and modify their response to natural stimuli. The present experiments utilized [125I]alpha-bungarotoxin [( 125I]alpha-BGT) to localize within the chemosensory tissue the possible sites of action of exogenous and endogenous nicotinic cholinergic substances. In vitro equilibrium binding studies of intact carotid bodies determined a Kd of 5.57 nM and a Bmax of 9.21 pmol/g of tissue. Chronic section (12-15 days) of the carotid sinus nerve (CSN) did not change the amount of displaceable toxin binding. In contrast, the specific binding was reduced by 46% following removal of the superior cervical ganglion. Light microscope autoradiography of normal, CSN-denervated and sympathectomized carotid bodies revealed displaceable binding sites concentrated in lobules of type I and type II cells. Treatment of carotid bodies with 50 nM alpha-BGT in vitro reduced by 50% the release of [3H]dopamine (synthesized from [3H]tyrosine) caused by hypoxia or nicotine, and also significantly reduced the stimulus-evoked discharges recorded from the CSN. The data suggest an absence of alpha-BGT binding sites on the afferent terminals of the CSN and that nicotinic receptors located with parenchymal cell lobules may modulate the release of catecholamines from these cells.
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Ceña V, García AG, Montiel C, Sánchez-García P. Uptake of [3H]-nicotine and [3H]-noradrenaline by cultured chromaffin cells. Br J Pharmacol 1984; 81:119-23. [PMID: 6704577 PMCID: PMC1986953 DOI: 10.1111/j.1476-5381.1984.tb10751.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Three day-old cultured bovine adrenal chromaffin cells incubated at room temperature with Krebs-HEPES solution containing different concentrations of [3H]-nicotine, took up and retained increasing amounts of the drug by a mechanism that did not saturate. Concentrations of cold nicotine as high as 100 microM did not alter the amount of [3H]-nicotine retained by cells. Imipramine, cocaine, tetracaine or mecamylamine, at concentrations (10 microM) that blocked the catecholamine secretory effects of nicotine completely, did not modify the uptake of [3H]-nicotine. Both imipramine and cocaine drastically inhibited [3H]-noradrenaline uptake by cells in a concentration-dependent manner (IC50S of 0.08 and 1 microM, respectively). These data indicate that the secretory effects of nicotine are not coupled to its previous uptake into cells, and are evidence in favour of a site of action for nicotine located in or at the surface of the chromaffin cell membrane.
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Osswald W, Guimarães S. Adrenergic mechanisms in blood vessels: morphological and pharmacological aspects. Rev Physiol Biochem Pharmacol 1983; 96:53-122. [PMID: 6338573 DOI: 10.1007/bfb0031007] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Nedergaard OA. Dual effect of the muscarinic agonist McN-A-343 on vascular neuroeffector transmission. ACTA PHARMACOLOGICA ET TOXICOLOGICA 1981; 49:354-65. [PMID: 6179387 DOI: 10.1111/j.1600-0773.1981.tb00917.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The site and mechanism of action of McN-A-343 (4-m-chlorophenylcarbamoyloxy)-2-butynyltrime-thylammonium chloride) on sympathetic neuroeffector transmission in the rabbit isolated pulmonary artery was studied. Low concentrations (10(-6) - 3 x 10(-5) M) of McN-A-343 and cocaine enhanced (up to 210 and 236%, respectively) the contractions evoked by electrical-field stimulation, while higher concentrations (10(-4) -3 x 10(-4)M) inhibited them. McN-A-343 (10(-4)M) caused an initial transitory potentiation (222% of control) of the stimulation-evoked contractions followed by an inhibition. In the presence of cocaine (3 x 10(-5)M), the potentiation caused by McN-A-343 was prolonged and the secondary inhibitory phase was thus abolished. Physostigmine (10(-5) - 10(-4)M), hexamethonium (10(-5) M), atropine (3 x 10(-7) M), suprofen (10(-5) M), and 4-aminopyridine did not alter the effect of McN-A-343 (1-(-4)M). Cocaine (3 x 10(-5)M) and (+)-amphetamine (10(-5) M) reversed the McN-A-343-evoked block, while they did not alter the inhibition caused by tetracaine (3.2 x 10(-5) M). Atropine (3 x 10(-7) M) had no effect on the McN-A-343-induced block, while 4-aminopyridine (10(-4) M) caused a partial and transitory reversal. On the aorta McN-A-343 (10(-4)M) did not alter the contractile concentration-response curve of (-)-noradrenaline (10(-9) - 3 x 10(-4)M), while that of serotonin (10(-8) - 3 x 10(-5)M) was moved to the right in a competitive manner. McN-A-343 (10(-4)M) did not alter the contractions evoked by noradrenaline (10(-7) M) during the period corresponding to the stimulation-evoked enhancement and subsequent inhibition. McN-A-343 (10(-4)M) slightly antagonized the contractions caused by tyramine (10(-6) - 10(-3) M) and carbachol (10(-6) - 10(-3) M). It is concluded that McN-A-343 enhances stimulation-evoked transmitter release by a presynaptic facilitatory action mediated via receptors localized on the outer surface of adrenergic neurones and to a lesser extent by inhibition of noradrenaline re-uptake. The enhancement does not involve presynaptic nicotine or muscarine receptors. Furthermore, McN-A-343 inhibits transmitter release by acting as an adrenergic neurone blocking agent at an intraneuronal site. The inhibition does not involve presynaptic muscarine inhibitory receptors and is prostaglandin-independent.
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Starke K, Weitzell R. gamma-Aminobutyric acid and postganglionic sympathetic transmission in the pulmonary artery of the rabbit. JOURNAL OF AUTONOMIC PHARMACOLOGY 1980; 1:45-51. [PMID: 6281282 DOI: 10.1111/j.1474-8673.1980.tb00440.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
1 The effect of gamma-aminobutyric acid (GABA) on postganglionic sympathetic neurotransmission was studied in strips of the rabbit pulmonary artery. The strips were preincubated with 3H-noradrenaline and then superfused with 3H-amine-free medium. They were stimulated either electrically at 2 Hz, or by 60 mM potassium, or by 1 microM tyramine. 2 GABA (1 - 1000 microM) did not change the basal outflow of tritium, but decreased the electrically evoked overflow as well as the contractile response. GABA 1 microM decreased the evoked overflow by 12%, and GABA 1000 microM, by 42%. The effect of GABA was not changed by yohimbine, propranolol, cocaine, corticosterone, or indomethacin. It was not antagonized by picrotoxin or bicuculline methiodide. GABA 100 microM also slightly reduced the potassium-evoked overflow of tritium but did not change the tyramine-evoked overflow. 3 The results show that, in the pulmonary artery of the rabbit, GABA inhibits the release of noradrenaline. Its effect is independent of alpha- and beta-adrenoreceptors and is not mediated by prostaglandins. The effect may be due to activation of presynaptic receptors which appear to differ from conventional GABA receptors inasmuch as they are insensitive to blockade by either picrotoxin or bicuculline.
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Sarantos-Laska C, McCulloch MW, Rand MJ. Facilitatory effect of nicotine on adrenergic neuroeffector transmission in the isolated ear artery of the rabbit. J Pharm Pharmacol 1980; 32:92-6. [PMID: 6103049 DOI: 10.1111/j.2042-7158.1980.tb12859.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The effects of nicotine were studied on perfusion pressure and vasoconstrictor responses to sympathetic nerve stimulation in the isolated ear artery of the rabbit. Infusions of nicotine (50 micro M) produced a transient increase in perfusion pressure and potentiated responses to nerve stimulation; these effects of nicotine were unaffected by atropine (0.3 micro M) and abolished or significantly reduced respectively by hexamethonium (300 micro M) or mecamylamine (1 micro M). In experiments with ear arteries previously labelled with [3H] noradrenaline an infusion of nicotine (50 micro M) produced a transient increase in tritium efflux and the potentiation of responses to nerve stimulation in the presence of nicotine was accompanied by a statistically significant increase in stimulation-induced tritium efflux; these effects of nicotine were abolished by hexamethonium (300 micro M) or mecamylamine (1 micro M).
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Schrold J, Nedergaard OA. Frequency-dependence of the metabolism of 3H-noradrenaline released from rabbit isolated aorta: effects of a combination of cocaine and corticosterone or hydrocortisone. ACTA PHARMACOLOGICA ET TOXICOLOGICA 1979; 44:13-21. [PMID: 760383 DOI: 10.1111/j.1600-0773.1979.tb02289.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Starke K, Weitzell R. Is histamine involved in the sympathomimetic effect of nicotine? NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1978; 304:237-48. [PMID: 714180 DOI: 10.1007/bf00507964] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Holbach HJ, Lindmar R, Löffelholz K. DMPP and the adrenergic nerve terminal: mechanisms of noradrenaline release from vesicular and extravesicular compartments. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1977; 300:131-8. [PMID: 593434 DOI: 10.1007/bf00505043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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