In vivo stimulation of sympathetic nervous system modulates osteoblastic activity in mouse calvaria

Ayami Kondo and Akifumi Togari

Department of Pharmacology, School of Dentistry, Aichi-Gakuin University, Nagoya 464-8650, Japan

Submitted 21 January 2003 ; accepted in final form 25 April 2003


    ABSTRACT
 TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 DISCLOSURES
 REFERENCES
 
Previously, we demonstrated that epinephrine induced the expression of interleukin (IL)-6 mRNA via {beta}-adrenoceptors in cultured human osteoblastic cells. IL-6 is well known to modulate bone metabolism by regulating the development and function of osteoclasts and osteoblasts. Recently, restraint stress and intracerebroventricular injection of lipopolysaccharide (LPS) have been reported to induce the expression of IL-6 mRNA in peripheral organs in mice in which expression is mediated by the activation of the sympathetic nervous system. To prove the physiological role of sympathetic nerves in bone metabolism in vivo, we examined by RT-PCR analysis the effects of restraint stress and intracerebroventricular injection of LPS on IL-6 mRNA expression in mouse calvaria. The expression of IL-6 mRNA in mouse calvaria was stimulated by either restraint stress (30 min) or intracerebroventricular injection of LPS (50 ng/mouse, 60 min). The treatment of mice with the neurotoxin 6-hydroxydopamine (6-OHDA, 100 mg · kg-1 · day-1 ip for 3 days) inhibited LPS (icv)-induced expression of IL-6 mRNA in their calvaria. The expression of IL-6 mRNA induced by the restraint stress was not influenced by 6-OHDA, which destroys noradrenergic nerve terminals. Furthermore, pretreatment with a {beta}-blocker, propranolol (15 or 25 mg/kg ip), inhibited both stress- and LPS-induced increases in the level of IL-6 mRNA, but pretreatment with an {alpha}-blocker, phentolamine (5 mg/kg sc), did not inhibit them in mouse calvaria. In addition, treatment of calvaria with isoprenaline or norepinephrine increased IL-6 synthesis in the organ culture system. These results indicate that in vivo adrenergic stimulation modulates the osteoblastic activity in mouse calvaria via noradrenergic nerve terminals.

restraint stress; intracerebroventricular injection; interleukin-6; lipopolysaccharide; calvaria; sympathetic activity; osteoblast


HISTOCHEMICAL AND PHARMACOLOGICAL STUDIES indicate the involvement of neural regulation in bone metabolism mediated by osteoblastic and osteoclastic cells. Mammalian bones are widely innervated by sympathetic and sensory nerves, which are particularly abundant in regions of high osteogenic activity, such as the growth plate (4, 15). In heterotropic bone formation induced by demineralized bone matrix, an early in-growth of noradrenergic nerves has been detected (5). Moreover, chemical denervation of sympathetic and/or sensory nerves has been demonstrated to modulate the number of bone-resorbing osteoclasts (6, 14). These observations suggest that sympathetic and/or sensory innervation is required for regulating bone metabolism under physiological and pathological conditions. It is well known that {beta}-adrenergic agonists can stimulate bone resorption in the intact mouse calvaria (19). The stimulation may be mediated by the activation of osteoclastic cells and/or the production of osteotrophic factor by osteoblastic cells, which factor is capable of stimulating the development of osteoclasts from their hematopoietic precursors. Recently, we observed that epinephrine increased the expression of osteotrophic factors, such as interleukin (IL)-6, IL-11, PGE2, and receptor activator of NF-{kappa}B ligand (RANKL; see Refs. 16 and 29), as well as the formation of osteoclast-like cells from mouse bone marrow cells by activating {beta}-adrenoceptors (29). These in vitro evidences may suggest that osteoblastic-mediated osteoclastogenesis is regulated by sympathetic activity in vivo.Go


View this table:
[in this window]
[in a new window]
 
Table 4. Data of ANOVA for the ratio of stress-or LPS-increased IL-6 mRNA in phentolamine-treated mice calvariae

 

Administration of lipopolysaccharide (LPS) has been shown to increase the norepinephrine (NE) turnover rate in various brain areas and peripheral tissues (1, 12). Recent experiments showed that the intracerebroventricular injection of LPS induced a marked increase in the level of IL-6 in the bloodstream and in IL-6 mRNA expression in the brain and peripheral organs (20, 23). The increases in plasma IL-6 levels by centrally injected LPS were reported to be inhibited by the intraperitoneal administration of adrenergic antagonists, suggesting the involvement of the NE system in the central LPS-induced IL-6 response (11). Immobilization stress also induced an increase in plasma IL-6 levels (27). As in the case of the central LPS-induced IL-6 response, depletion of NE was reported to inhibit the stress-induced increase in plasma IL-6 (27). Thus the peripheral sympathetic nervous system may be involved in the increase of IL-6 in peripheral tissues induced by both centrally injected LPS and immobilization stress.

In the present study, to determine whether sympathetic activity is involved in bone metabolism in vivo, we examined the expression of IL-6 mRNA in calvariae dissected from mice treated intracerebroventricularly with LPS or subjected to restraint stress to stimulate sympathetic activity, and we pharmacologically characterized the IL-6 expression induced by the central LPS or physiological stress. All experiments were performed in accordance with the guidelines for animal experiments at the School of Dentistry, Aichi-Gakuin University.


    MATERIALS AND METHODS
 TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 DISCLOSURES
 REFERENCES
 
Animals and reagents. Conventional male and pregnant female ICR mice were obtained from SLC (Hamamatsu, Shizuoka, Japan). Mice were caged in plastic tubs covered with stainless-steel tops and containing hardwood-chip bedding under automatically controlled conditions of temperature (23-25°C), humidity (50 ± 10%), and a 12:12-h light-dark cycle and were given ad libitum tap water and rodent chow. LPS from Escherichia coli serotype 026:B6 (phenol extracted), propranolol, 6-hydroxydopamine (6-OHDA), phentolamine, NE, isoprenaline (ISP), and phenylephrine were purchased from Sigma (St. Louis, MO). 6-OHDA was dissolved in saline containing 0.1% ascorbic acid. Other reagents were dissolved in saline.

Restraint stress. Five-week-old ICR mice were restrained individually by keeping them in a 50-ml disposable syringe (with volume set for 25-30 ml) with some holes for the desired period. Mice kept unrestrained at room temperature served as controls. After the restraint stress, the calvaria was removed immediately, and the total RNA was extracted by the guanudinium-thiocyanate method (7). In the experiment of chemical denervation, the mice were pretreated with 6-OHDA (100 mg/kg ip) or vehicle for 3 days before being subjected to the restraint stress. In the experiment of receptor blockage, the mice were pretreated with propranolol (15 mg/kg sc), phentolamine (5 mg/kg ip), or saline for 10 min before the restraint stress.

Intracerebroventricular injection of LPS. The intracerebroventricular administration of LPS was performed by following the method of Haley and McCormick (13). Simply stated, ICR mice were injected under ether anesthesia 1 mm lateral and 1 mm anteroposterior to the bregma with a Hamilton syringe (10 µl) fitted with a 27-gauge needle. The intracerebroventricular injection volume was 5 µl, and the injection sites were verified by injection of the same volume of methylene blue in the sites. After the injection of LPS, the calvariae were obtained at various times for analysis of the expression of IL-6 mRNA. Mice were pretreated with 6-OHDA (100 mg/kg ip) or vehicle for 3 days before the injection of LPS. Other mice were pretreated with propranolol (25 mg/kg ip), phentolamine (5 mg/kg ip), or saline for 10 min before the injection of LPS (icv).

Analysis of mRNA levels by RT-PCR. RNA was extracted from mouse calvaria by the guanidinium-thiocyanate method. The total RNA was solubilized in 1 ml guanidinium thiocyanate buffer/calvaria from a mouse and then extracted with phenol and treated with DNase I (Boehringer Mannheim). cDNA was synthesized by using random primer and Moloney murine leukemia virus RT (GIBCO-BRL, Grand Island, NY), and subsequent PCR amplification was done by using synthetic gene primers specific for mouse IL-6 and mouse glyceraldehyde-3-phosphate dehydrogenase (GAPDH) produced from their respective reported cDNA sequences (2, 12). The oligonucleotide primers were synthesized on a DNA synthesizer (Expedite model 8909; PerSeptiv Biosystem, Cambridge, MA) and purified on a polypropylene filter (Oligo Prep kit; Pharmacia Biotech, Uppsala, Sweden). GAPDH primers (forward primer 5'-ACCACAGTCCATGCCATCAC-3', reverse primer 5'-TCCACCACCCTTTGCTGTA-3') were used to amplify a 452-bp cDNA fragment, and mouse IL-6 primers (forward primer 5'-GAAATGAGAAAAGAGTTGTGC-3', reverse primer 5'-ATTGGAAATTGGGGTAGGAAG-3') were used to amplify a 324-bp cDNA fragment. PCR amplification was performed by using a GeneAmp PCR System (Perkin-Elmer/Cetus, Norwalk, CT) under the following conditions: denaturation at 95°C for 15 s, annealing at 55°C or 30 s, and elongation at 72°C for 30 s for the appropriate number of cycles. PCR products were electrophoresed on a 2% NuSive GTG agarose gel (FMC BioProducts, Rockland, ME), stained with ethidium bromide, and detected on a fluoroimage analyzer (FluorImager 575; Molecular Dynamics, Sunnyvale, CA). All PCR data were obtained from the measurements, which were performed in the linear range of PCR amplification.

Analysis of IL-6 production in calvaria culture system. Calvariae (frontal and parietal) were aseptically removed from 2- or 3-day-old mice. They were preincubated in medium containing 100 U/ml penicillin and 100 µg/ml streptomycin for 18 h at 37°C in air with 5% CO2. Then calvariae were treated with NE (100 µM), ISP (100 µM), or phenylephrine (100 µM) for 24 h, and condition medium was used for analysis of IL-6 synthesis. IL-6 in condition medium was quantified using an ELISA kit (R&D Systems, Minneapolis, MN).

Statistical analysis. All data were presented as means ± SE. Statistical analysis was carried out by one-way or two-way ANOVA. Fisher's protected least significant difference post hoc test was used when multiple groups were compared (Figs. 2, 3, 4), and Student's t-test was used when groups were compared with a single control group (Figs. 1 and 5).



View larger version (37K):
[in this window]
[in a new window]
 
Fig. 2. Effect of 6-hydroxydopamine (6-OHDA) on restraint stress-induced (A) and LPS-induced (B) increases in the IL-6 mRNA levels in mouse calvaria. a: RT-PCR analysis of mRNA obtained from mouse calvaria. Mice were injected with either vehicle (-) or 100 mg/kg 6-OHDA (+) for 3 days. Later (3 days), the effects of restraint stress (A) for 0 (-) or 30 (+) min and central LPS administration (B) at 0 (-) or 50 (+) ng/mouse for 60 min were examined. Arrowheads indicate the predicted sizes of PCR products, and nos. in parentheses indicate cycles for PCR amplification. DNA size markers ({varphi}X174-Hae III digest) are shown on left (S). Data shown are representative of 6 similar experiments. b: Relative expression of these increases. Values are means ± SE of 6 mice. *P < 0.05 vs. control mice (--). #P < 0.05 vs. control mice with 6-OHDA (-+).

 


View larger version (41K):
[in this window]
[in a new window]
 
Fig. 3. Effect of propranolol on restraint stress-induced (A) and LPS-induced (B) increases in the IL-6 mRNA levels in mouse calvaria. a: RT-PCR analysis for mRNA obtained from mouse calvaria. Mice were injected with either vehicle (-) or 15 mg/kg propranolol (Pro; +). Later (10 min), the effects of restraint stress (A) for 0 (-) or 30 (+) min or central LPS administration (B) at 0 (-) or 50 (+) ng/mouse for 60 min were examined. Arrowheads indicate the PCR production of predicted sizes, and nos. in parentheses indicate cycles for PCR amplification. DNA size markers ({varphi}X174-Hae III digest) are shown on left (S). Data shown are representative of 6 similar experiments. b, Relative expression of these increases. Values are means ± SE of 6 mice. *P < 0.01 vs. control mice (--).

 


View larger version (20K):
[in this window]
[in a new window]
 
Fig. 4. Effect of phentolamine on restraint stress-induced (A) and LPS-induced (B) increases in the IL-6 mRNA levels in mouse calvaria. Relative expression of IL-6 was calculated by dividing the intensity of the IL-6 band by that of the GAPDH band as determined with a fluorescent image analyzer. Mice were injected with either vehicle (-) or 5 mg/kg phentolamine (Ph; +). Later (10 min), the effects of restraint stress (A) for 0 (-) or 30 (+) min or central LPS administration (B) at 0 (-) or 50 (+) ng/mouse for 60 min were examined. Values are means ± SE of 6 mice. *P < 0.01 vs. control mice (--). #P < 0.05 vs. control mice with Ph (-+).

 


View larger version (58K):
[in this window]
[in a new window]
 
Fig. 1. RT-PCR analysis of mRNA obtained from calvariae of mice treated with restraint stress (A) or icv lipopolysaccharide (LPS; B and C). A: a, RT-PCR analysis of mRNA obtained from mouse calvaria. Mice were subjected to a restraint stress for 0 (no stress), 15, 30, or 60 min. DNA size markers ({varphi}X174-Hae III digest) are shown on left (S). Arrowheads indicate the predicted size of PCR products. Nos. in parentheses indicate cycles for PCR amplification. Data shown are representative of 6 similar experiments. b, relative expression of these increases. The mRNA level of interleukin (IL)-6 was calculated by dividing the intensity of the IL-6 band by that of the GAPDH band as determined by fluorescent image analyzer. Values are means ± SE of 6 mice. *P < 0.05 vs. nonstressed mice (0 min). B: a, RT-PCR analysis of mRNA obtained from mouse calvaria. Mice were treated with LPS (50 ng/mouse icv) for 0 (nontreatment), 30, 60, or 120 min. Data shown are representative of 6 similar experiments; b, relative expression of these increases. Values are means ± SE of 6 mice. *P < 0.01 vs. nontreated mice (0 min). C: a, mice were treated with 0 (saline), 0.5, 5, or 50 ng/mouse LPS (icv) for 60 min. Data shown are representative of 6 similar experiments; b, relative expression of these increases. Values are means ± SE of 6 mice. *P < 0.01 vs. saline-treated mice (0 ng/mouse).

 


View larger version (10K):
[in this window]
[in a new window]
 
Fig. 5. Changes of IL-6 synthesis in calvaria cultivated with norepinephrine (NE), isoprenalin (ISP), or phenylephrine (PHN). Calvariae dissected from 2- or 3-day old mice were preincubated for 18 h, and then calvariae were treated with norepinephrine (100 µM), isoprenaline (100 µM), or phenylephrine (100 µM). Conditioned media were used for analysis of IL-6 synthesis by the ELISA system. Values are means ± SE of 5 calvariae. *P < 0.05 vs. control (CTRL).

 


    RESULTS
 TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 DISCLOSURES
 REFERENCES
 
The effects of restraint stress and intracerebroventricular LPS on IL-6 mRNA levels in mouse calvaria are shown in Fig. 1. RT-PCR analysis revealed a low level of IL-6 mRNA in the mouse calvaria, which was increased by exposure of the mice to restraint stress for 30 min. The restraint stress for 15 min was not sufficient to increase the IL-6 mRNA levels (Fig. 1A). Restraint stress for 30 min increased the plasma epinephrine level in mice (Table 1). Figure 1B shows the effect of LPS (icv) on the IL-6 mRNA levels in mouse calvaria. Treatment of mice with LPS (50 ng/mouse icv) for 60-120 min significantly increased the IL-6 mRNA levels in the calvaria. The increase by treatment with LPS for 30 min was lower than that by treatment for 60 or 120 min (Fig. 1B). The dose-dependent effect of LPS on the IL-6 mRNA levels in the calvaria is shown in Fig. 1C. By treatment of mice with LPS (icv) for 60 min, the dose-dependent increase in the IL-6 mRNA level was observed at a dose of 0.5-50 ng/mouse.


View this table:
[in this window]
[in a new window]
 
Table 1. Effect of restraint stress on plasma catecholamine

 

To determine whether the restraint stress-induced and LPS (icv)-induced increases in the IL-6 mRNA in mouse calvaria required peripheral NE nerve activity, we examined the effect of 6-OHDA (well known to destroy NE nerve terminals) on these increases in IL-6 mRNA levels. Table 1 shows the results of ANOVA for the effects of LPS, stress, and 6-OHDA on IL-6 mRNA in mouse calvaria. In the expression of IL-6 mRNA, there were significant differences in the LPS group (P < 0.001) and stress group (P < 0.05) in mouse calvaria. However, there were no significant differences in the interaction of stress and 6-OHDA, but there were significant differences in the interaction of LPS and 6-OHDA (P < 0.001). As shown in Fig. 2A, the 2.8-fold increase in the IL-6 mRNA levels in calvaria by restraint stress for 30 min was not influenced by the pretreatment of mice with 6-OHDA. Actually, this pretreatment with 6-OHDA caused a slight increase over the level obtained by the stress. On the other hand, the 2.6-fold increase in the IL-6 mRNA levels caused by treatment with LPS (50 ng/mouse icv) for 60 min was inhibited by pretreatment with 6-OHDA (Fig. 2B).

To find out whether the restraint stress-induced and LPS (icv)-induced increases in IL-6 mRNA in mouse calvaria were mediated by adrenoceptors in the calvaria, we examined the effect of propranolol, a {beta}-adrenergic antagonist, and phentolamine, an {alpha}-adrenergic antagonist, on these increases in the IL-6 mRNA level. Tables 2 and 3 show the results of ANOVA for the effects of LPS, stress, propranolol, and phentolamine on IL-6 mRNA in mouse calvaria. There were significant differences in the interaction of stress and propranolol (P < 0.05) but no differences in the interaction of stress and phentolamine. Furthermore, there were significant differences in the interaction of LPS and propranolol (P < 0.01) but no significant differences in the interaction of LPS and phentolamine. As shown in Fig. 3A, pretreatment with propranolol (15 mg/kg ip) inhibited the restraint stress-induced increase in the IL-6 mRNA level in mouse calvaria. Similarly, pretreatment with propranolol (25 mg/kg ip) inhibited the LPS-induced increase as well (Fig. 3B). However, pretreatment with propranolol (15 mg/kg sc) did not inhibit the LPS-induced increase (data not shown). In contrast, pretreatment with phentolamine (5 mg/kg ip) did not affect either the restraint stress-induced or the LPS-induced increase in IL-6 mRNA levels in mouse calvaria (Fig. 4, A and B).


View this table:
[in this window]
[in a new window]
 
Table 2. Data of ANOVA for the ratio of stressor LPS-increased IL-6 mRNA in 6-OHDA-treated mice calvaria

 

View this table:
[in this window]
[in a new window]
 
Table 3. Data of ANOVA for the ratio of stress- or LPS-increased IL-6 mRNA in propranolol-treated mice calvariae

 

As shown in Fig. 5, treatment with 100 µM NE or 100 µM ISP for 24 h increased IL-6 synthesis in mouse calvaria. However, treatment with 100 µM phenylephrine for 24 h did not affect IL-6 synthesis.


    DISCUSSION
 TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 DISCLOSURES
 REFERENCES
 
It has been demonstrated that human osteoblastic and osteoclastic cells are equipped with adrenergic receptors and neuropeptide receptors and that they constitutively express diffusible axon guidance molecules that are known to function as a chemoattractant and/or a chemorepellent for growing never fibers (30-32). These recent findings, in addition to immunohistochemical and pharmacological findings, suggest that the extension of axons of sympathetic and peripheral sensory nerves to osteoblastic and osteoclastic cells is required for the dynamic neural regulation of local bone metabolism. Recently, adrenergic stimulation was shown to increase the expression of osteotrophic factors, such as IL-6, IL-11, PGE2, or RANKL, which is identical to osteoclast differentiation factor, via {beta}-adrenoceptors in osteoblastic cells (16, 29). Furthermore, both Takeda et al. (28) and Baldock et al. (3) have recently provided pharmacological genetic evidence that hypothalamic autonomic signals proceeding via the {beta}-adrenoceptor regulate bone mass. In association with an increase of sympathetic nerve activity, application of stress (21, 27, 33) and central administration of LPS (8, 9, 18) were shown to increase the IL-6 levels in rodents. These findings led us to evaluate the calvaria expression of IL-6 mRNA under the sympathomimetic condition caused by central LPS injection or restraint stress to assess the physiological significance of sympathetic nerve activity on bone metabolism in vivo.

In the present study, we observed elevated IL-6 mRNA expression in the calvaria of mice subjected to central LPS injection or restraint stress. The significant elevation by central LPS injection was prevented by the destruction of NE nerve terminals by use of 6-OHDA (17), or by blockage of {beta}-adrenoceptors with propranolol, suggesting that the elevation of IL-6 mRNA in the calvaria was mediated by the activation of postganglion sympathetic nerve fibers innervating the calvaria and by {beta}-adrenoceptors in the calvaria. On the other hand, the elevation by restraint stress was prevented by blockage of {beta}-adrenoceptors but not by the destruction of NE nerve terminals, suggesting that the elevation is mediated by elevated secretion of epinephrine from the adrenals. In fact, restraint stress for 30 min caused a significant increase (P < 0.05) in plasma epinephrine in comparison with the level in control mice (Table 1). Although it is likely that the effects of propranolol on this expression could be a result of antagonism of {beta}-adrenoceptors in another tissue, with a concomitant decrease of an intermediate factor that is responsible for stimulating the increase in IL-6 mRNA levels, the possibility may be contradicted by a direct increase of IL-6 protein in calvaria treated with {beta}-adrenoceptor activation (Fig. 5). Although several evidences demonstrated the existence of the {alpha}-adrenoceptor in human and mouse osteoblasts (26, 30), phenylephrine did not increase IL-6 synthesis in mouse calvaria. These data suggested that peripheral NE increased IL-6 synthesis via {beta}-adrenoceptor activation. This is the first report to demonstrate that physiological and pharmacological stimulation of the sympathetic nervous system modulates bone metabolic activity in vivo, as evaluated by expression of IL-6 mRNA in calvaria.

In the bone microenvironment, there is a dynamic balance between resorption and formation that maintains skeletal homeostasis. Osteoclastic bone resorption consists of multiple steps, such as the differentiation of osteoclast precursor in mononuclear prefusion osteoclasts, the fusion of prefusion osteoclasts to form multinucleate osteoclasts, and the activation of these osteoclasts to resorb bone (22, 25). These steps seem to progress at the site of bone resorption under the control osteotrophic hormones locally produced in the micro-environment (24). Potential paracrine mediators of osteoclast activity include monocyte-macrophage colony-stimulating factor, tumor necrosis factor (TNF)-{alpha}, IL-1, IL-6, IL-11, PGE2, and RANKL/osteoprotegerin ligand/TNF-related activation-induced cytokine, all of which are capable of increasing osteoclastogenesis. It is well known that activation of {beta}-adrenoceptors on osteoblastic cells can stimulate bone resorption in intact mouse calvaria (19) and induce the expression of osteotrophic factors, such as IL-6, IL-11, PGE2, or RANKL (16, 29). In the present study, we showed the in vivo sympathomimetic action on the expression of IL-6 mRNA. These evidences suggest that the activity of sympathetic nerves has a significant effect on osteoclastogenesis by modulation of the expression of osteotrophic factors in osteoblastic cells and support the observation that bone resorption in rats was reduced after sympathectomy induced by guanethidine, which specifically destroys sympathetic adrenergic fibers (6). Further studies should clarify the involvement of sympathetic innervation of osteoblastic cells and give insight into the mechanism of sympathetic regulation of bone metabolism.

In conclusion, the findings indicate that restraint stress increased IL-6 mRNA expression via peripheral epinephrine from the adrenal glands and that LPS (icv) increased IL-6 mRNA expression via peripheral NE from sympathetic postganglionic fibers in the mouse calvaria. In consideration of the physiological significance of IL-6 in bone metabolism, we propose that sympathomimetic action on calvaria may be part of the mechanism governing bone resorption.


    DISCLOSURES
 TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 DISCLOSURES
 REFERENCES
 
This study was partly supported by a grant-in-aid for Scientific Frontier Promoted Research and by a grant-in-aid for Scientific Research from the Ministry of Education, Science, Sport and Culture of Japan (nos. 11671861 and 14571782 to A. Togari).


    FOOTNOTES
 

Address for reprint requests and other correspondence: A. Togari, Dept. of Pharmacology, School of Dentistry, Aichi-Gakuin Univ., Nagoya 464-8650, Japan (E-mail: togariaf{at}dpc.aichi-gakuin.ac.jp).

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.


    REFERENCES
 TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 DISCLOSURES
 REFERENCES
 

  1. Akiyoshi M, Shimizu Y, and Saito M. Interleukin-1 increases norepinephrine turnover in the spleen and lung in rats. Biochem Biophys Res Commun 173: 1266-1270, 1990.[ISI][Medline]
  2. Arcari P, Martinelli R, and Salvatore F. The complete sequence of a full length cDNA for humasn liver glyceraldehyde-3-phosphate dehydrogenase: evidence for multiple mRNA species. Nucleic Acids Res 12: 9178-9189, 1984.
  3. Baldock PA, Sainsbury A, Couzens M, Enriquez RF, Thomas GP, Gardiner EM, and Herzog H. Hypothalamic Y2 receptors regulate bone formation. J Clin Invest 109: 915-921, 2002.[Abstract/Free Full Text]
  4. Bjurholm A. Neuroendocrine peptides in bone. Int Orthop 15: 325-329, 1991.[ISI][Medline]
  5. Bjurholm A, Kreicbergs A, Dahlberg L, and Schultzberg M. The occurrence of neuropeptides at different stages of DBM-induced heterotopic bone formation. Bone Miner 10: 95-107, 1990.[ISI][Medline]
  6. Cherruau M, Facchinetti P, Baroukh B, and Saffar JL. Chemical sympathectomy impairs bone resorption in rats: a role for the sympathetic system on bone metabolism. Bone 25: 545-551, 1999.[ISI][Medline]
  7. Chomczynski P and Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem 162: 156-159, 1987.[ISI][Medline]
  8. De Simoni MG, De Luigi A, Gemma L, Sironi M, Manfridi A, and Ghezzi P. Modulation of systemic interleukin-6 induction by central interleukin-1. Am J Physiol Endocrinol Metab 265: E739-E742, 1993.
  9. De Simoni MG, Sironi M, De Luigi A, Manfridi A, Mantovani A, and Ghezzi P. Intracerebroventricular injection of interleukin 1 induces high circulating levels of interleukin 6. J Exp Med 171: 1773-1778, 1990.[Abstract]
  10. Dunn AJ. Endotoxin-induced activation of cerebral catecholamine and serotonin metabolism: comparison with interleukin-1. J Pharmacol Exp Ther 261: 964-969, 1992.[Abstract]
  11. Finck BN, Dantzer R, Kelley KW, Woods JA, and Johnson RW. Central lipopolysaccharide elevates plasma IL-6 concentration by an {alpha}-adrenoceptor-mediated mechanism. Am J Physiol Endocrinol Metab 272: E1880-E1887, 1997.
  12. Grenett HE, Fuentes NL, and Fuller GM. Cloning and sequence analysis of the cDNA for murine interleukin-6 (Abstract). Nucleic Acids Res 18: 6455, 1990.[ISI][Medline]
  13. Haley TJ and McCormick WG. Pharmacological effects produced by intracerebral injection of drugs in the conscious mouse. Br J Pharmacol 12: 12-15, 1957.
  14. Hill EL, Turner R, and Elde R. Effects of neonatal sympathectomy and capsaicin treatment on bone remodeling in rats. Neuroscience 44: 747-755, 1991.[ISI][Medline]
  15. Hohmann EL, Elde RP, Rysavy JA, Einzig S, and Gebhard RL. Innervation of periosteum and bone by sympathetic vasoactive intestinal peptide-containing nerve fibers. Science 232: 868-871, 1986.[ISI][Medline]
  16. Kondo A, Mogi M, Koshihara Y, and Togari A. Signal transduction system for interleukin-6 and interleukin-11 synthesis stimulated by epinephrine in human osteoblasts and human osteogenic sarcoma cells. Biochem Pharmacol 61: 319-326, 2001.[ISI][Medline]
  17. Kostrzewa RM and Jacobowitz DM. Pharmacological actions of 6-hydroxydopamine. Pharmacol Rev 26: 199-288, 1974.[ISI][Medline]
  18. LeMay LG, Otterness IG, Vander AJ, and Kluger MJ. In vivo evidence that the rise in plasma IL 6 following injection of a fever-inducing dose of LPS is mediated by IL 1 beta. Cytokine 2: 199-204, 1990.[Medline]
  19. Moore RE, Smith CK II, Bailey CS, Voelkel EF, and Tashijian AH. Characterization of beta-adrenergic receptors on rat and human osteoblast-like cells and demonstration that beta-receptor agonists can stimulate bone. Bone Miner 23: 301-315, 1993.[ISI][Medline]
  20. Murammai N, Fukata J, Tsukada T, Kobayashi H, Ebisui O, Segawa H, Muro S, Imura H, and Nakao K. Bacterial lipopolysaccharide-induced expression of interleukin-6 messenger ribonucleic acid in the rat hypothalamus, pituitary, adrenal grand, and spleen. Endocrinology 133: 2574-2578, 1993.[Abstract]
  21. Papanicolaou DA, Petrides JS, Tsigos C, Bina S, Kalogeras KT, Wilder R, Gold PW, Deuster PA, and Chrousos GP. Exercise stimulates interleukin-6 secretion: inhibition by glucocorticoids and correlation with catecholamines. Am J Physiol Endocrinol Metab 271: E601-E605, 1996.[Abstract/Free Full Text]
  22. Roodman GD. Advances in bone biology: the osteoclast. Endocr Rev 17: 308-332, 1996.[Abstract]
  23. Song DK, Im YB, Jung JS, Suh HW, Huh SO, Park SW, Wie MB, and Kim YH. Differential involvement of central and peripheral norepinephrine in the central lipopolysaccharide-induced interleukin-6 responses in mice. J Neurochem 72: 1625-1633, 1999.[ISI][Medline]
  24. Suda T, Takahashi N, and Martin TJ. Modulation of osteoclast differentiation. Endocr Rev 13: 66-80, 1992.[ISI][Medline]
  25. Suda T, Udagawa N, Nakamura I, Miyamura C, and Takahashi N. Modulation of osteoclast differentiation by local factors. Bone 17: 87S-91S, 1995.[Medline]
  26. Suzuki A, Palmer G, Bonjour JP, and Caverzasio J. Catecholamines stimulate the proliferation and alkaline phosphatase activity of MC3T3-E1 osteoblast-like cells. Bone 23: 197-203, 1998.[ISI][Medline]
  27. Takaki A, Huang QH, Somogyvari-Vigh A, and Arimura A. Immobilization stress may increase plasma interleukin-6 via central and peripheral catecholamines. Neuroimmunomodulation 1: 335-342, 1994.[Medline]
  28. Takeda S, Elefteriou F, Levasseur R, Liu X, Zhao L, Parker KL, Armstrong D, Ducy P, and Karsenty G. Leptin regulates bone formation via the sympathetic nervous system. Cell 111: 305-317, 2002.[ISI][Medline]
  29. Takeuchi T, Tsuboi T, Arai M, and Togari A. Adrenergic stimulation of osteoclastogenesis mediated by expression of osteoclast differentiation factor in MC3T3-E1 osteoblast-like cells. Biochem Pharmacol 61: 579-586, 2001.[ISI][Medline]
  30. Togari A. Adrenergic regulation of bone metabolism: possible involvement of sympathetic innervation of osteoblastic and osteoclastic cells. Microsc Res Tech 58: 77-84, 2002.[ISI][Medline]
  31. Togari A, Arai M, Mizutani S, Mizutani S, Koshihara Y, and Nagatsu T. Expression of mRNAs for neuropeptide receptors and {beta}-adrenergic receptors in human osteoblasts and human osteogenic sarcoma cells. Neurosci Lett 233: 125-128, 1997.[ISI][Medline]
  32. Togari A, Mogi M, Arai M, Yamamoto S, and Koshihara Y. Expression of mRNA for axon guidance molecules, such as semaphorin-III, netrins and neurotrophins, in human osteoblasts and osteoclasts. Brain Res 878: 204-209, 2000.[ISI][Medline]
  33. Zhou D, Kusnecov AW, Shurin MR, DePaoli M, and Rabin BS. Exposure to physical and psychological stressors elevates plasma interleukin 6: relationship to the activation of hypothalamic-pituitary-adrenal axis. Endocrinology 133: 2523-2530, 1993.[Abstract]




This Article
Abstract
Full Text (PDF)
Alert me when this article is cited
Alert me if a correction is posted
Citation Map
Services
Email this article to a friend
Similar articles in this journal
Similar articles in ISI Web of Science
Similar articles in PubMed
Alert me to new issues of the journal
Download to citation manager
Search for citing articles in:
ISI Web of Science (8)
Google Scholar
Articles by Kondo, A.
Articles by Togari, A.
Articles citing this Article
PubMed
PubMed Citation
Articles by Kondo, A.
Articles by Togari, A.


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2003 by the American Physiological Society.