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Ishii K, Matsukawa K, Asahara R, Liang N, Endo K, Idesako M, Michioka K, Sasaki Y, Hamada H, Yamashita K, Watanabe T, Kataoka T, Takahashi M. Central command increases muscular oxygenation of the non-exercising arm at the early period of voluntary one-armed cranking. Physiol Rep 2017; 5:5/7/e13237. [PMID: 28381448 PMCID: PMC5392523 DOI: 10.14814/phy2.13237] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 11/24/2022] Open
Abstract
This study aimed to examine whether central command increases oxygenation in non‐contracting arm muscles during contralateral one‐armed cranking and whether the oxygenation response caused by central command differs among skeletal muscles of the non‐exercising upper limb. In 13 male subjects, the relative changes in oxygenated‐hemoglobin concentration (Oxy‐Hb) of the non‐contracting arm muscles [the anterior deltoid, triceps brachii, biceps brachii, and extensor carpi radialis (ECR)] were measured during voluntary one‐armed cranking (intensity, 35–40% of maximal voluntary effort) and mental imagery of the one‐armed exercise for 1 min. Voluntary one‐armed cranking increased (P < 0.05) the Oxy‐Hb of the triceps, biceps, and ECR muscles to the same extent (15 ± 4% of the baseline level, 17 ± 5%, and 16 ± 4%, respectively). The greatest increase in the Oxy‐Hb was observed in the deltoid muscle. Intravenous injection of atropine (10–15 μg/kg) and/or propranolol (0.1 mg/kg) revealed that the increased Oxy‐Hb of the arm muscles consisted of the rapid atropine‐sensitive and delayed propranolol‐sensitive components. Mental imagery of the exercise increased the Oxy‐Hb of the arm muscles. Motor‐driven passive one‐armed cranking had little influence on the Oxy‐Hb of the arm muscles. It is likely that central command plays a role in the initial increase in oxygenation in the non‐contracting arm muscles via sympathetic cholinergic vasodilatation at the early period of one‐armed cranking. The centrally induced increase in oxygenation may not be different among the distal arm muscles but may augment in the deltoid muscle.
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Affiliation(s)
- Kei Ishii
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.,Automotive Human Factors Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Kanji Matsukawa
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Ryota Asahara
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Nan Liang
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kana Endo
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Mitsuhiro Idesako
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kensuke Michioka
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Yu Sasaki
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hironobu Hamada
- Department of Physical Analysis and Therapeutic Sciences, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kaori Yamashita
- Department of Health Care for Adults, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Tae Watanabe
- Department of Health Care for Adults, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Tsuyoshi Kataoka
- Department of Health Care for Adults, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Makoto Takahashi
- Department of Biomechanics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Kocaman A, Gül M, Yurt KK, Altun G, Zayman E, Kıvrak EG. Does omega-3 have a protective effect on the rat adrenal gland exposed to 900 MHz electromagnetic fields? J Microsc Ultrastruct 2017; 5:185-190. [PMID: 30023253 PMCID: PMC6025787 DOI: 10.1016/j.jmau.2017.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/25/2017] [Accepted: 08/30/2017] [Indexed: 11/26/2022] Open
Abstract
The aim of this study was to investigate the harmful effects of exposure to 900-megahertz (MHz) electromagnetic fields (EMF) and the protective effects of omega-3 (Omg-3) against EMF in the rat adrenal gland. Eighteen Wistar albino rats were randomly assigned into three groups, control (Cont), EMF, and EMF + Omg-3. The EMF and EMF + Omg-3 groups both consisted of six rats exposed to an EMF of 900 MHz for 60 min/day for 15 days. No procedure was applied to the six rats in the Cont group. At the end of the experiment, all rats were sacrificed, and the mean volumes of the cortex and medulla of the adrenal gland were estimated using a stereological counting technique. The stereological results showed that the mean volume of the adrenal gland increased significantly in the EMF-exposed groups compared to the Cont group. Additionally, the mean volume of the adrenal gland was significantly lower in the EMF + Omg-3 group compared to the EMF group. We suggest that Omg-3 therapy aimed at suppressing the effects of EMF may prove a safe alternative for animals, whether or not they are exposed to EMF.
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Affiliation(s)
- Adem Kocaman
- Department of Histology and Embryology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Mehmet Gül
- Department of Histology and Embryology, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Kıymet Kübra Yurt
- Department of Histology and Embryology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Gamze Altun
- Department of Histology and Embryology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Emrah Zayman
- Department of Histology and Embryology, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Elfide Gizem Kıvrak
- Department of Histology and Embryology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
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De Nardi F, Lefort C, Bréard D, Richomme P, Legros C, Guérineau NC. Monitoring the Secretory Behavior of the Rat Adrenal Medulla by High-Performance Liquid Chromatography-Based Catecholamine Assay from Slice Supernatants. Front Endocrinol (Lausanne) 2017; 8:248. [PMID: 28993760 PMCID: PMC5622411 DOI: 10.3389/fendo.2017.00248] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/11/2017] [Indexed: 12/21/2022] Open
Abstract
Catecholamine (CA) secretion from the adrenal medullary tissue is a key step of the adaptive response triggered by an organism to cope with stress. Whereas molecular and cellular secretory processes have been extensively studied at the single chromaffin cell level, data available for the whole gland level are much scarcer. We tackled this issue in rat by developing an easy to implement experimental strategy combining the adrenal acute slice supernatant collection with a high-performance liquid chromatography-based epinephrine and norepinephrine (NE) assay. This technique affords a convenient method for measuring basal and stimulated CA release from single acute slices, allowing thus to individually address the secretory function of the left and right glands. Our data point that the two glands are equally competent to secrete epinephrine and NE, exhibiting an equivalent epinephrine:NE ratio, both at rest and in response to a cholinergic stimulation. Nicotine is, however, more efficient than acetylcholine to evoke NE release. A pharmacological challenge with hexamethonium, an α3-containing nicotinic acetylcholine receptor antagonist, disclosed that epinephrine- and NE-secreting chromaffin cells distinctly expressed α3 nicotinic receptors, with a dominant contribution in NE cells. As such, beyond the novelty of CA assays from acute slice supernatants, our study contributes at refining the secretory behavior of the rat adrenal medullary tissue, and opens new perspectives for monitoring the release of other hormones and transmitters, especially those involved in the stress response.
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Affiliation(s)
- Frédéric De Nardi
- Mitochondrial and Cardiovascular Pathophysiology – MITOVASC, CNRS UMR6015, INSERM U1083, UBL/Angers University, Angers, France
| | - Claudie Lefort
- Mitochondrial and Cardiovascular Pathophysiology – MITOVASC, CNRS UMR6015, INSERM U1083, UBL/Angers University, Angers, France
| | - Dimitri Bréard
- EA921, SONAS, SFR QUASAV, UBL/Angers University, Angers, France
| | - Pascal Richomme
- EA921, SONAS, SFR QUASAV, UBL/Angers University, Angers, France
| | - Christian Legros
- Mitochondrial and Cardiovascular Pathophysiology – MITOVASC, CNRS UMR6015, INSERM U1083, UBL/Angers University, Angers, France
- *Correspondence: Christian Legros, ; Nathalie C. Guérineau,
| | - Nathalie C. Guérineau
- Mitochondrial and Cardiovascular Pathophysiology – MITOVASC, CNRS UMR6015, INSERM U1083, UBL/Angers University, Angers, France
- *Correspondence: Christian Legros, ; Nathalie C. Guérineau,
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Matsukawa K, Ishii K, Asahara R, Idesako M. Central command does not suppress baroreflex control of cardiac sympathetic nerve activity at the onset of spontaneous motor activity in the decerebrate cat. J Appl Physiol (1985) 2016; 121:932-943. [PMID: 27539494 DOI: 10.1152/japplphysiol.00299.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/11/2016] [Indexed: 11/22/2022] Open
Abstract
Our laboratory has reported that central command blunts the sensitivity of the aortic baroreceptor-heart rate (HR) reflex at the onset of voluntary static exercise in animals. We have examined whether baroreflex control of cardiac sympathetic nerve activity (CSNA) and/or cardiovagal baroreflex sensitivity are altered at the onset of spontaneously occurring motor behavior, which was monitored with tibial nerve activity in paralyzed, decerebrate cats. CSNA exhibited a peak increase (126 ± 17%) immediately after exercise onset, followed by increases in HR and mean arterial pressure (MAP). With development of the pressor response, CSNA and HR decreased near baseline, although spontaneous motor activity was not terminated. Atropine methyl nitrate (0.1-0.2 mg/kg iv) with little central influence delayed the initial increase in HR but did not alter the response magnitudes of HR and CSNA, while atropine augmented the pressor response. The baroreflex-induced decreases in CSNA and HR elicited by brief occlusion of the abdominal aorta were challenged at the onset of spontaneous motor activity. Spontaneous motor activity blunted the baroreflex reduction in HR by aortic occlusion but did not alter the baroreflex inhibition of CSNA. Similarly, atropine abolished the baroreflex reduction in HR but did not influence the baroreflex inhibition of CSNA. Thus it is likely that central command increases CSNA and decreases cardiac vagal outflow at the onset of spontaneous motor activity while preserving baroreflex control of CSNA. Accordingly, central command must attenuate cardiovagal baroreflex sensitivity against an excess rise in MAP as estimated from the effect of muscarinic blockade.
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Affiliation(s)
- Kanji Matsukawa
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kei Ishii
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Ryota Asahara
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Mitsuhiro Idesako
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Verberne AJM, Korim WS, Sabetghadam A, Llewellyn-Smith IJ. Adrenaline: insights into its metabolic roles in hypoglycaemia and diabetes. Br J Pharmacol 2016; 173:1425-37. [PMID: 26896587 DOI: 10.1111/bph.13458] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 01/20/2016] [Accepted: 02/11/2016] [Indexed: 01/05/2023] Open
Abstract
Adrenaline is a hormone that has profound actions on the cardiovascular system and is also a mediator of the fight-or-flight response. Adrenaline is now increasingly recognized as an important metabolic hormone that helps mobilize energy stores in the form of glucose and free fatty acids in preparation for physical activity or for recovery from hypoglycaemia. Recovery from hypoglycaemia is termed counter-regulation and involves the suppression of endogenous insulin secretion, activation of glucagon secretion from pancreatic α-cells and activation of adrenaline secretion. Secretion of adrenaline is controlled by presympathetic neurons in the rostroventrolateral medulla, which are, in turn, under the control of central and/or peripheral glucose-sensing neurons. Adrenaline is particularly important for counter-regulation in individuals with type 1 (insulin-dependent) diabetes because these patients do not produce endogenous insulin and also lose their ability to secrete glucagon soon after diagnosis. Type 1 diabetic patients are therefore critically dependent on adrenaline for restoration of normoglycaemia and attenuation or loss of this response in the hypoglycaemia unawareness condition can have serious, sometimes fatal, consequences. Understanding the neural control of hypoglycaemia-induced adrenaline secretion is likely to identify new therapeutic targets for treating this potentially life-threatening condition.
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Affiliation(s)
- A J M Verberne
- Clinical Pharmacology and Therapeutics Unit, Department of Medicine, Austin Health, University of Melbourne, Heidelberg, VIC, Australia
| | - W S Korim
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - A Sabetghadam
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - I J Llewellyn-Smith
- Cardiovascular Medicine and Human Physiology, Flinders University, Bedford Park, SA, Australia
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Ishii K, Matsukawa K, Liang N, Endo K, Idesako M, Hamada H, Kataoka T, Ueno K, Watanabe T, Takahashi M. Differential contribution of ACh-muscarinic and β-adrenergic receptors to vasodilatation in noncontracting muscle during voluntary one-legged exercise. Physiol Rep 2014; 2:e12202. [PMID: 25413322 PMCID: PMC4255809 DOI: 10.14814/phy2.12202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/15/2014] [Accepted: 10/15/2014] [Indexed: 12/21/2022] Open
Abstract
We have demonstrated the centrally induced cholinergic vasodilatation in skeletal muscle at the early period of voluntary one-legged exercise and during motor imagery in humans. The purpose of this study was to examine whether central command may also cause β-adrenergic vasodilatation during the exercise and motor imagery. Relative changes in oxygenated hemoglobin concentration (Oxy-Hb) of bilateral vastus lateralis (VL) muscles, as index of tissue blood flow, and femoral blood flow to nonexercising limb were measured during one-legged cycling and mental imagery of the exercise for 1 min before and after propranolol (0.1 mg/kg iv). The Oxy-Hb of noncontracting muscle increased (P < 0.05) at the early period of exercise and the increase was sustained throughout exercise, whereas the Oxy-Hb of contracting muscle increased at the early period but thereafter decreased. We subtracted the Oxy-Hb response with propranolol from the control response in individual subjects to identify the propranolol-sensitive component of the Oxy-Hb response during exercise. In both noncontracting and contracting VL muscles, the increase in Oxy-Hb at the early period of one-legged exercise did not involve a significant propranolol-sensitive component. However, as the exercise proceeded, the propranolol-sensitive component of the Oxy-Hb response was developed during the later period of exercise. Propranolol also failed to affect the initial increases in femoral blood flow and vascular conductance of nonexercising leg but significantly attenuated (P < 0.05) their later increases during exercise. Subsequent atropine (10-15 μg/kg iv) abolished the initial increases in Oxy-Hb of both VL muscles. Mental imagery of the one-legged exercise caused the bilateral increases in Oxy-Hb, which were not altered by propranolol but abolished by subsequent atropine. It is likely that the rapid cholinergic and delayed β-adrenergic vasodilator mechanisms cooperate to increase muscle blood flow during exercise.
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Affiliation(s)
- Kei Ishii
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kanji Matsukawa
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Nan Liang
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kana Endo
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Mitsuhiro Idesako
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hironobu Hamada
- Department of Physical Analysis and Therapeutic Sciences, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Tsuyoshi Kataoka
- Department of Health Care for Adults, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kazumi Ueno
- Department of Health Care for Adults, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Tae Watanabe
- Department of Health Care for Adults, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Makoto Takahashi
- Department of Biomechanics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Effect of ascorbic acid deficiency on catecholamine synthesis in adrenal glands of SMP30/GNL knockout mice. Eur J Nutr 2013; 53:177-85. [DOI: 10.1007/s00394-013-0515-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 03/06/2013] [Indexed: 12/13/2022]
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Sato D, Shinzawa G, Kusunoki M, Matsui T, Sasaki H, Feng Z, Nishina A, Nakamura T. Effects of electrical microstimulation of peripheral sympathetic nervous fascicle on glucose uptake in rats. J Artif Organs 2013; 16:352-8. [PMID: 23468373 DOI: 10.1007/s10047-013-0700-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 02/24/2013] [Indexed: 11/25/2022]
Abstract
Artificial pancreas systems control insulin-mediated glucose uptake. Although these systems are widely used in the clinical setting, they are still fraught with structural and biological problems. The non-insulin mediated glucose uptake (NIMGU) mechanism could be an alternative candidate as a target system for the artificial control of peripheral glucose uptake. Although the sympathetic nervous system is known to be one of the regulators of NIMGU, the effects of peripheral sympathetic activation on glucose uptake have not been well documented. We electrically stimulated a sympathetic nerve fascicle to clarify the possibility of controlling peripheral glucose uptake. A sympathetic signal was microneurographically obtained in the unilateral sciatic nerve in normal (NRML), insulin-resistant high-fat-fed (HFF), and streptozotocin-induced insulin-depleted (STZ) rats, and electrical stimulation was applied via the microelectrode (microstimulation). The microstimulation was also applied to sites other than the sympathetic fascicles in an additional group of normal rats (NSYMP group). The stimulation applied to the sympathetic fibers resulted in an immediate and transient decrease of blood glucose (BG) in the NRML, HFF, and STZ groups, with little change in the plasma insulin. The change in BG level seemed to depend on the basal BG level (NRML < HFF < STZ). In contrast, no reduction in BG was observed in the NSYMP group. These results suggest that microstimulation in the peripheral sympathetic fascicle could enhance glucose uptake in peripheral tissues-independently of insulin function-and show an alternative possibility for controlling glucose uptake.
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Affiliation(s)
- Daisuke Sato
- Department of Biomedical Information Engineering, Graduate School of Medical Science, Yamagata University, 2-2-2 Iida-nishi, Yamagata, 990-9585, Japan,
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Amano A, Tsunoda M, Aigaki T, Maruyama N, Ishigami A. Age-related changes of dopamine, noradrenaline and adrenaline in adrenal glands of mice. Geriatr Gerontol Int 2012; 13:490-6. [PMID: 22934574 DOI: 10.1111/j.1447-0594.2012.00929.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM Catecholamines, which are physiologically important neurotransmitters and hormones, apparently decrease in the brain and plasma as some species age. Because this observation has engendered controversy, we used mice to investigate whether age-related changes occur in adrenal catecholamine levels and in the expression of catecholamine synthetic enzymes. METHODS Adrenal glands were collected from male C57BL/6NCr mice at the ages of 6, 12 and 24 months. Catecholamines, such as dopamine (DA), noradrenaline (NA) and adrenaline (AD) from those glands, were measured by using a highly sensitive liquid chromatographic method with peroxyoxalate chemiluminescence reaction detection. Tyrosine hydroxylase (TH), dopa decarboxylase, dopamine beta hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) mRNA expression levels were measured by quantitative real-time polymerase chain reaction. RESULTS Although DA levels in the adrenals of 24-month-old mice were higher than in 6- and 12-month-old mice, the AD content decreased with age. In such mice, the ratio of DA to NA at 24 months was lower than at 12 months, and the ratio of NA to AD content at 24 months was significantly lower than at 6 months. The mRNA expression ratios in TH, DBH and PNMT in 24-month-old mice were all lower than in 12-month-old mice. CONCLUSIONS These results strongly suggest that catecholamine synthesis, in general, declines with aging in the adrenal glands of mice and that AD, in particular, undergoes a significant decrease with advancing age.
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Affiliation(s)
- Akiko Amano
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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Hoffmann TJ, Simon BJ, Zhang Y, Emala CW. Low voltage vagal nerve stimulation reduces bronchoconstriction in guinea pigs through catecholamine release. Neuromodulation 2012; 15:527-36. [PMID: 22551486 DOI: 10.1111/j.1525-1403.2012.00454.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Electrical stimulation of the vagus nerve at relatively high voltages (e.g., >10 V) can induce bronchoconstriction. However, low voltage (≤2 V) vagus nerve stimulation (VNS) can attenuate histamine-invoked bronchoconstriction. Here, we identify the mechanism for this inhibition. METHODS In urethanea-nesthetized guinea pigs, bipolar electrodes were attached to both vagus nerves and changes in pulmonary inflation pressure were recorded in response to i.v. histamine and during VNS. The attenuation of the histamine response by low-voltage VNS was then examined in the presence of pharmacologic inhibitors or nerve ligation. RESULTS Low-voltage VNS attenuated histamine-induced bronchoconstriction (4.4 ± 0.3 vs. 3.2 ± 0.2 cm H(2) O, p < 0.01) and remained effective following administration of a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester, and after sympathetic nerve depletion with guanethidine, but not after the β-adrenoceptor antagonist propranolol. Nerve ligation caudal to the electrodes did not block the inhibition but cephalic nerve ligation did. Low-voltage VNS increased circulating epinephrine and norepinephrine without but not with cephalic nerve ligation. CONCLUSION These results indicate that low-voltage VNS attenuates histamine-induced bronchoconstriction via activation of afferent nerves, resulting in a systemic increase in catecholamines likely arising from the adrenal medulla.
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Affiliation(s)
- Thomas J Hoffmann
- ElectroCore LLC, Morris Plains, NJ, USA; and Department of Anesthesiology, Columbia University, New York, NY, USA
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Verberne AJM, Sartor DM. Rostroventrolateral medullary neurons modulate glucose homeostasis in the rat. Am J Physiol Endocrinol Metab 2010; 299:E802-7. [PMID: 20807841 DOI: 10.1152/ajpendo.00466.2010] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Several lines of evidence support the view that the premotor sympathetic input to the adrenal gland arises from the rostroventrolateral medulla (RVLM). The aim of this study was to determine whether RVLM neurons play a role in glucose homeostasis. We identified RVLM neurons that control epinephrine secretion by searching for medullospinal neurons that responded to neuroglucoprivation induced by systemic 2-deoxyglucose (2-DG) administration. We tested the effect of disinhibition of the RVLM on arterial blood pressure and plasma glucose concentration. RVLM medullospinal barosensitive neurons (n = 17) were either unaffected or slightly inhibited by 2-DG. In contrast, we found a group (n = 6) of spinally projecting neurons that were excited by 2-DG administration. These neurons were not barosensitive and had spinal conduction velocities in the unmyelinated range (<1 m/s). These neurons may mediate epinephrine secretion and participate in the counterregulatory responses to neuroglucoprivation. To test the hypothesis that activation of the RVLM leads to adrenomedullary activation and subsequent hyperglycemia, we applied the GABA(A) antagonist bicuculline to the RVLM and measured blood pressure, heart rate, and blood glucose in rats with intact adrenals or after bilateral adrenalectomy. Disinhibition of the RVLM resulted in hypertension, tachycardia, and hyperglycemia (4.9 ± 0.3 to 14.7 ± 0.9 mM, n = 5, P < 0.05). Adrenalectomy significantly reduced the hyperglycemic response but did not alter the cardiovascular responses. These data suggest that the RVLM is a key component of the neurocircuitry that is recruited in the counterregulatory response to hypoglycemia.
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Affiliation(s)
- A J M Verberne
- Department of Medicine, University of Melbourne, Heidelberg, Victoria, Australia.
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Wakasugi R, Nakamoto T, Matsukawa K. The effects of adrenalectomy and autonomic blockades on the exercise tachycardia in conscious rats. Auton Neurosci 2010; 155:59-67. [PMID: 20153986 DOI: 10.1016/j.autneu.2010.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 01/12/2010] [Accepted: 01/12/2010] [Indexed: 11/15/2022]
Abstract
Heart rate (HR) during exercise is controlled by cardiac sympathetic (CSNA) and vagal (CVNA) efferent nerve activity and plasma catecholamines. To determine their relative contribution to the exercise tachycardia, we examined the effects of adrenalectomy (ADX) and autonomic blockades on the HR response during treadmill exercise for 32min in 13 conscious rats. The baseline HR was not influenced by ADX, suggesting no significant role of adrenal catecholamines on the baseline HR. Since the baseline HR was increased 61beats/min by atropine methyl nitrate (1.5mg/kg) and decreased 26beats/min by atenolol (3mg/kg), CVNA determined the baseline HR more than CSNA. ADX did not affect the immediate increase in HR at 0-12s from the exercise onset but reduced the subsequent increase in HR at 13-30s. These increases in HR at the early period of exercise were more blunted by atenolol than atropine. On the other hand, the peak tachycardia response of 99+/-8beats/min at the end of exercise, which was the same between the intact and ADX conditions, was blunted to 73% by atenolol, to 77% by atropine, and to 35% by combined atenolol and atropine, respectively. In conclusion, it is likely that the tachycardia at the beginning of dynamic exercise is predominantly determined by the cardiac autonomic nerve activity, especially by a prompt increase in CSNA, and that the hormonal mechanism due to adrenal epinephrine contributes to a further increase in HR approximately in 13s from the onset of exercise.
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Affiliation(s)
- Rie Wakasugi
- Department of Physiology, Graduate School of Health Sciences, Hiroshima University, Hiroshima 734-8551, Japan
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