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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.
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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
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2
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Lopez-Delisle L, Pierre-Eugène C, Bloch-Gallego E, Birling MC, Duband JL, Durand E, Bourgeois T, Matrot B, Sorg T, Huerre M, Meziane H, Roux MJ, Champy MF, Gallego J, Delattre O, Janoueix-Lerosey I. Hyperactivation of Alk induces neonatal lethality in knock-in AlkF1178L mice. Oncotarget 2015; 5:2703-13. [PMID: 24811761 PMCID: PMC4058038 DOI: 10.18632/oncotarget.1882] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The ALK (Anaplastic Lymphoma Kinase) gene encodes a tyrosine kinase receptor preferentially expressed in the central and peripheral nervous systems. A syndromic presentation associating congenital neuroblastoma with severe encephalopathy and an abnormal shape of the brainstem has been described in patients harbouring de novo germline F1174V and F1245V ALK mutations. Here, we investigated the phenotype of knock-in (KI) mice bearing the AlkF1178L mutation (F1174L in human). Although heterozygous KI mice did not reproduce the severe breathing and feeding difficulties observed in human patients, behavioral tests documented a reduced activity during dark phases and an increased anxiety of mutated mice. Matings of heterozygotes yielded the expected proportions of wild-type, heterozygotes and homozygotes at birth but a high neonatal lethality was noticed for homozygotes. We documented Alk expression in several motor nuclei of the brainstem involved in the control of sucking and swallowing. Evaluation of basic physiological functions 12 hours after birth revealed slightly more apneas but a dramatic reduced milk intake for homozygotes compared to control littermates. Overall, our data demonstrate that Alk activation above a critical threshold is not compatible with survival in mice, in agreement with the extremely severe phenotype of patients carrying aggressive de novo ALK germline mutations.
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Avraam J, Cohen G, Drago J, Frappell PB. Prenatal nicotine exposure increases hyperventilation in α4-knock-out mice during mild asphyxia. Respir Physiol Neurobiol 2015; 208:29-36. [PMID: 25596543 DOI: 10.1016/j.resp.2015.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/07/2015] [Accepted: 01/08/2015] [Indexed: 10/24/2022]
Abstract
Prenatal nicotine exposure alters breathing and ventilatory responses to stress through stimulation of nicotine acetylcholine receptors (nAChRs). We tested the hypothesis that α4-containing nAChRs are involved in mediating the effects of prenatal nicotine exposure on ventilatory and metabolic responses to intermittent mild asphyxia (MA). Using open-flow plethysmography, we measured ventilation (V̇(E)) and rate of O2 consumption ( V̇(O2)) of wild-type (WT) and α4-knock-out (KO) mice, at postnatal (P) days 1-2 and 7-8, with and without prenatal nicotine exposure (6 mg kg(-1) day(-1) beginning on embryonic day 14). Mice were exposed to seven 2 min cycles of mild asphyxia (10% O2 and 5% CO2), each interspersed with 2 min of air. Compared to WT, α4 KO mice had increased air V̇(E) and V̇(O2) at P7-8, but not P1-2. Irrespective of age, genotype had no effect on the hyperventilatory response (increase in V̇(E)/V̇(O2)) to MA. At P1-2, nicotine suppressed air V̇(E) and V̇(O2) in both genotypes but did not affect the hyperventilatory response to MA. At P7-8 nicotine suppressed air V̇(E) and V̇(O2) of only α4 KO's but also significantly enhanced V̇(E) during MA (nearly double that of WT; p<0.001). This study has revealed complex effects of α4 nAChR deficiency and prenatal nicotine exposure on ventilatory and metabolic interactions and responses to stress.
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Affiliation(s)
- Joanne Avraam
- Department of Zoology, Latrobe University, Melbourne, VIC 3086, Australia.
| | - Gary Cohen
- Department of Women & Child Health, Neonatal Unit, Karolinska Institute, Elevhemmet H1:02 S171-76, Stockholm, Sweden
| | - John Drago
- Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC 3052, Australia
| | - Peter B Frappell
- Department of Zoology, Latrobe University, Melbourne, VIC 3086, Australia; Adaptational and Evolutionary Respiratory Physiology Laboratory, School of Zoology, Hobart, TAS, Australia
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Clark CG, Sun Z, Meininger GA, Potts JT. Atomic force microscopy to characterize binding properties of α7-containing nicotinic acetylcholine receptors on neurokinin-1 receptor-expressing medullary respiratory neurons. Exp Physiol 2012; 98:415-24. [PMID: 22962286 DOI: 10.1113/expphysiol.2012.067660] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the present study, we used atomic force microscopy (AFM) to examine the ligand-binding properties of α7-containing nicotinic acetylcholine receptors (nAChRs) expressed on neurons from the ventral respiratory group. We also determined the effect of acute and prolonged exposure to nicotine on the binding probability of nAChRs. Neurons from neonatal (postnatal day 5-10) and juvenile rats (3-4 weeks old) were cultured. Internalization of Alexa Fluor 488-conjugated substance P was used to identify respiratory neurons that expressed the neurokinin-1 receptor (NK1-R), a recognized marker of ventral respiratory group neurons. To assess functional changes in nAChRs, AFM probes conjugated with anti-α7 subunit nAChR antibody were used to interact cyclically with the surface of the soma of NK1-R-positive neurons. Measurements were made of the frequency of antibody adhesion to the α7 receptor subunit and of the detachment forces between the membrane-attached receptor and the AFM probe tip. Addition of α-bungarotoxin (a specific antagonist of α7 subunit-containing nAChRs) to the cell bath produced a 69% reduction in binding to the α7 subunit (P < 0.05, n = 10), supporting specificity of binding. Acute exposure to nicotine (1 μM added to culture media) produced an 80% reduction in nAChR antibody binding to the α7 subunit (P < 0.05, n = 9). Prolonged incubation (72 h) of the cell culture in nicotine significantly reduced α7 binding in a concentration-dependent manner. Collectively, these findings demonstrate that AFM is a sensitive tool for assessment of functional changes in nAChRs expressed on the surface of living NK1-R-expressing medullary neurons. Moreover, these data demonstrate that nicotine exposure decreases the binding probability of α7 subunit-containing nAChRs.
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Affiliation(s)
- Catharine G Clark
- Dalton Cardiovascular Research Center and Departments of Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA.
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Shirahata M, Kostuk EW, Pichard LE. Carotid chemoreceptor development in mice. Respir Physiol Neurobiol 2012; 185:20-9. [PMID: 22634368 DOI: 10.1016/j.resp.2012.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/17/2012] [Accepted: 05/18/2012] [Indexed: 10/28/2022]
Abstract
Mice are the most suitable species for understanding genetic aspects of postnatal developments of the carotid body due to the availability of many inbred strains and knockout mice. Our study has shown that the carotid body grows differentially in different mouse strains, indicating the involvement of genes. However, the small size hampers investigating functional development of the carotid body. Hypoxic and/or hyperoxic ventilatory responses have been investigated in newborn mice, but these responses are indirect assessment of the carotid body function. Therefore, we need to develop techniques of measuring carotid chemoreceptor neural activity from young mice. Many studies have taken advantage of the knockout mice to understand chemoreceptor function of the carotid body, but they are not always suitable for addressing postnatal development of the carotid body due to lethality during perinatal periods. Various inbred strains with well-designed experiments will provide useful information regarding genetic mechanisms of the postnatal carotid chemoreceptor development. Also, targeted gene deletion is a critical approach.
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Affiliation(s)
- Machiko Shirahata
- Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
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Michaud M, Arnoux T, Bielli S, Durand E, Rotrou Y, Jablonka S, Robert F, Giraudon-Paoli M, Riessland M, Mattei MG, Andriambeloson E, Wirth B, Sendtner M, Gallego J, Pruss RM, Bordet T. Neuromuscular defects and breathing disorders in a new mouse model of spinal muscular atrophy. Neurobiol Dis 2010; 38:125-35. [PMID: 20085811 DOI: 10.1016/j.nbd.2010.01.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 01/07/2010] [Accepted: 01/11/2010] [Indexed: 01/11/2023] Open
Abstract
Spinal muscular atrophy (SMA) is caused by insufficient levels of the survival motor neuron (SMN) protein leading to muscle paralysis and respiratory failure. In mouse, introducing the human SMN2 gene partially rescues Smn(-)(/)(-) embryonic lethality. However current models were either too severe or nearly unaffected precluding convenient drug testing for SMA. We report here new SMN2;Smn(-/-) lines carrying one to four copies of the human SMN2 gene. Mice carrying three SMN2 copies exhibited an intermediate phenotype with delayed appearance of motor defects and developmental breathing disorders reminiscent of those found in severe SMA patients. Although normal at birth, at 7 days of age respiratory rate was decreased and apnea frequency was increased in SMA mice in parallel with the appearance of neuromuscular junction defects in the diaphragm. With median survival of 15 days and postnatal onset of neurodegeneration, these mice could be an important tool for evaluating new therapeutics.
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Affiliation(s)
- Magali Michaud
- Trophos, Parc Scientifique de Luminy, Luminy Biotech Entreprise, Case 931, 13288 Marseille, France
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Bollen B, Bouslama M, Matrot B, Rotrou Y, Vardon G, Lofaso F, Van den Bergh O, D'Hooge R, Gallego J. Cold stimulates the behavioral response to hypoxia in newborn mice. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1503-11. [DOI: 10.1152/ajpregu.90582.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In newborns, hypoxia elicits increased ventilation, arousal followed by defensive movements, and cries. Cold is known to affect the ventilatory response to hypoxia, but whether it affects the arousal response remains unknown. The aim of the present study was to assess the effects of cold on the ventilatory and arousal responses to hypoxia in newborn mice. We designed an original platform measuring noninvasively and simultaneously the breathing pattern by whole body plethysmography, body temperature by infrared thermography, as well as motor and ultrasonic vocal (USV) responses. Six-day-old mice were exposed twice to 10% O2 for 3 min at either cold temperature (26°C) or thermoneutrality (33°C). At 33°C, hypoxia elicited a marked increase in ventilation followed by a small ventilatory decline, small motor response, and almost no USVs. Body temperature was not influenced by hypoxia, and oxygen consumption (V̇o2) displayed minimal changes. At 26°C, hypoxia elicited a slight increase in ventilation with a large ventilatory decline and a large drop of V̇o2. This response was accompanied by marked USV and motor responses. Hypoxia elicited a small decrease in temperature after the return to normoxia, thus precluding any causal influence on the motor and USV responses to hypoxia. In conclusion, cold stimulated arousal and stress responses to hypoxia, while depressing hypoxic hyperpnea. Arousal is an important defense mechanism against sleep-disordered breathing. The dissociation between ventilatory and behavioral responses to hypoxia suggests that deficits in the arousal response associated with sleep breathing disorders cannot be attributed to a depressed hypoxic response.
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Fregosi RF, Pilarski JQ. Prenatal nicotine exposure and development of nicotinic and fast amino acid-mediated neurotransmission in the control of breathing. Respir Physiol Neurobiol 2009; 164:80-6. [PMID: 18585984 DOI: 10.1016/j.resp.2008.05.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 05/08/2008] [Accepted: 05/13/2008] [Indexed: 10/22/2022]
Abstract
There is mounting evidence that neonatal animals exposed to nicotine in the prenatal period exhibit a variety of anatomic and functional abnormalities that adversely affect their respiratory and cardiovascular control systems, but how nicotine causes these developmental alterations is unknown. The principle that guides our work is that PNE impairs the ability of nicotinic acetylcholine receptors (nAChRs) to modulate the pre-synaptic release of both inhibitory (particularly GABA) and excitatory (glutamate) neurotransmitters, leading to marked alterations in the density and/or function of receptors on the (post-synaptic) membrane of respiratory neurons. Such changes could lead to impaired ventilatory responses to sensory afferent stimulation, and altered breathing patterns, including central apneic events. In this brief review we summarize the work that lead to the development of this hypothesis, and introduce some new data that support and extend it.
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Affiliation(s)
- Ralph F Fregosi
- Department of Physiology, The University ofArizona, College of Medicine, Tucson, AZ 85721-0093, USA.
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Borday C, Vias C, Autran S, Thoby-Brisson M, Champagnat J, Fortin G. The pre-Bötzinger oscillator in the mouse embryo. ACTA ACUST UNITED AC 2007; 100:284-9. [PMID: 17628453 DOI: 10.1016/j.jphysparis.2007.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Studies of the sites and mechanisms involved in mammalian respiratory rhythm generation point to two clusters of rhythmic neurons forming a coupled oscillator network within the brainstem. The location of these oscillators, the pre-Bötzinger complex (preBötC) at vagal level, and the para-facial respiratory group at facial level, probably result from regional patterning schemes specifying neural types in the hindbrain during embryogenesis. Here, we report evidence that the preBötC oscillator (i) is first active at embryonic stages, (ii) originates in the post-otic hindbrain neural tube and (iii) requires the glutamate vesicular transporter 2 for rhythm generation.
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Affiliation(s)
- C Borday
- Neurobiologie Génétique et Intégrative, Institut de Neurobiologie Alfred Fessard, CNRS, 1 av. de la terrasse, 91198 Gif sur Yvette, France
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10
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Wallén-Mackenzie Å, Gezelius H, Thoby-Brisson M, Nygård A, Enjin A, Fujiyama F, Fortin G, Kullander K. Vesicular glutamate transporter 2 is required for central respiratory rhythm generation but not for locomotor central pattern generation. J Neurosci 2006; 26:12294-307. [PMID: 17122055 PMCID: PMC6675433 DOI: 10.1523/jneurosci.3855-06.2006] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Glutamatergic excitatory neurotransmission is dependent on glutamate release from presynaptic vesicles loaded by three members of the solute carrier family, Slc17a6-8, which function as vesicular glutamate transporters (VGLUTs). Here, we show that VGLUT2 (Slc17a6) is required for life ex utero. Vglut2 null mutant mice die immediately after birth because of the absence of respiratory behavior. Investigations at embryonic stages revealed that neural circuits in the location of the pre-Bötzinger (PBC) inspiratory rhythm generator failed to become active. However, neurons with bursting pacemaker properties and anatomical integrity of the PBC area were preserved. Vesicles at asymmetric synapses were fewer and malformed in the Vglut2 null mutant hindbrain, probably causing the complete disruption of AMPA/kainate receptor-mediated synaptic activity in mutant PBC cells. The functional deficit results from an inability of PBC neurons to achieve synchronous activation. In contrast to respiratory rhythm generation, the locomotor central pattern generator of Vglut2 null mutant mice displayed normal rhythmic and coordinated activity, suggesting differences in their operating principles. Hence, the present study identifies VGLUT2-mediated signaling as an obligatory component of the developing respiratory rhythm generator.
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Affiliation(s)
- Åsa Wallén-Mackenzie
- Department of Neuroscience, Unit of Developmental Genetics, Uppsala University, 751 23 Uppsala, Sweden
| | - Henrik Gezelius
- Department of Neuroscience, Unit of Developmental Genetics, Uppsala University, 751 23 Uppsala, Sweden
| | - Muriel Thoby-Brisson
- Laboratoire de Neurobiologie Génétique et Intégrative, Institut Alfred Fessard, Centre National de la Recherche Scientifique, 91198 Gif sur Yvette, France, and
| | - Anna Nygård
- Department of Neuroscience, Unit of Developmental Genetics, Uppsala University, 751 23 Uppsala, Sweden
| | - Anders Enjin
- Department of Neuroscience, Unit of Developmental Genetics, Uppsala University, 751 23 Uppsala, Sweden
| | - Fumino Fujiyama
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Gilles Fortin
- Laboratoire de Neurobiologie Génétique et Intégrative, Institut Alfred Fessard, Centre National de la Recherche Scientifique, 91198 Gif sur Yvette, France, and
| | - Klas Kullander
- Department of Neuroscience, Unit of Developmental Genetics, Uppsala University, 751 23 Uppsala, Sweden
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Durand E, Dauger S, Pattyn A, Gaultier C, Goridis C, Gallego J. Sleep-disordered Breathing in Newborn Mice Heterozygous for the Transcription Factor Phox2b. Am J Respir Crit Care Med 2005; 172:238-43. [PMID: 15860752 DOI: 10.1164/rccm.200411-1528oc] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Central congenital hypoventilation syndrome (CCHS) is a rare autosomal dominant syndrome present from birth, and characterized by depressed ventilation during sleep. Heterozygous mutations of the homeobox gene Phox2b were recently found in a very high proportion of patients. OBJECTIVES To determine whether newborn mice with heterozygous targeted deletion of the transcription factor Phox2b would display sleep-disordered breathing. METHODS We measured breathing pattern using whole-body plethysmography in wild-type and mutant 5-day-old mice, and we classified sleep-wake states using nuchal EMG and behavioral scores. RESULTS We found that sleep apnea total time was approximately six times longer (8.9 +/- 12 vs. 1.5 +/- 2.2 seconds, p < 0.0015), and ventilation during active sleep was 21% lower (18.4 +/- 5.1 vs. 23.3 +/- 5.5 ml/g/second, p < 0.006) in mutant than in wild-type pups. During wakefulness, apnea time and ventilation were not significantly different between mutant and wild-type pups. Mutant and wild-type pups showed highly similar sleep-wake states. CONCLUSION Although their respiratory phenotype was much less severe than CCHS, the Phox2b(+/-) mutant mice showed sleep-disordered breathing, which partially modeled the key feature of CCHS.
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Affiliation(s)
- Estelle Durand
- INSERM U676, Hôpital Robert-Debré, 48 Boulevard Sérurier, 75019 Paris, France
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Matrot B, Durand E, Dauger S, Vardon G, Gaultier C, Gallego J. Automatic classification of activity and apneas using whole body plethysmography in newborn mice. J Appl Physiol (1985) 2005; 98:365-70. [PMID: 15591306 DOI: 10.1152/japplphysiol.00803.2004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
An increasing number of studies in newborn mice are being performed to determine the mechanisms of sleep apnea, which is the hallmark of early breathing disorders. Whole body plethysmography is the method of choice, as it does not require immobilization, which affects behavioral states and breathing. However, activity inside the plethysmograph may disturb the respiratory signal. Visual classification of the respiratory signal into ventilatory activity, activity-related disturbances, or apneas is so time-consuming as to considerably hamper the phenotyping of large pup samples. We propose an automatic classification of activity based on respiratory disturbances and of apneas based on spectral analysis. This method was validated in newborn mice on the day of birth and on postnatal days 2, 5, and 10, under normoxic and hypoxic (5% O2) conditions. For both activity and apneas, visual and automatic scores showed high Pearson's correlation coefficients (0.92 and 0.98, respectively) and high intraclass correlation coefficients (0.96–0.99), supporting strong agreement between the two methods. The present results suggest that breathing disturbances may provide a valid indirect index of activity in freely moving newborn mice and that automatic apnea classification based on spectral analysis may be efficient in terms of precision and of time saved.
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Affiliation(s)
- B Matrot
- Laboratoire de Neurologie et Physiologie du Développement, INSERM-E9935, Hôpital Robert-Debré, 48 Boulevard Sérurier, 75010 Paris, France
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