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The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, La Jolla, California 92037
Address all correspondence and requests for reprints to: Wylie W. Vale, Ph.D., The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037. E-mail: vale{at}salk.edu
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Introduction |
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(4), CRF R2ß (5, 6, 7), and CRF
R2
(12). In the rat, CRF R2 messenger RNA (mRNA) is found
primarily in the brain, including sites in the hypothalamus, lateral
septum, raphe nuclei of the midbrain, and olfactory bulb (13). By
contrast, among other sites, rat CRF R2ß mRNA is predominantly
expressed in the heart, gastrointestinal tract, arterioles, and
muscles (7, 13). R2 was recently identified in human brain (12), but
it has not yet been found in the rodent.
The natural ligand for CRF R2 is most likely not CRF. CRF has
approximately 20-fold lower affinity for CRF R2 than it has for CRF R1
(14). In the rat brain, CRF immunoreactive fibers do not colocalize
well with CRF R2-containing neurons. Instead, it is likely that
urocortin (Ucn), a 40-amino acid, novel CRF family peptide discovered
in mammals, is an endogenous CRF R2 ligand. Ucn has a 45% sequence
identity to rat/human CRF and a 63% identity to the fish peptide,
urotensin (14). Ucn has a 40-fold higher affinity for CRF R2 than does
CRF. In rodent and human tissues, Ucn-like immunoreactivity and mRNA
have been reported in the thymus, spleen, stomach, intestine, testis
and liver (15, 16), lymphocytes (17), pituitary (18), placental and
fetal membranes (19), as well as the brain (20, 21). The distribution
of Ucn or urotensin-like immunoreactive fibers in the brain correlates
with the distribution of CRF R2 rather than CRF R1 (14). Ucn mRNA
and peptide were also found in rat heart and cardiac myocytes (16, 22).
The administration of CRF or Ucn has positive inotropic effects on the
heart in vivo and in vitro (23, 24). Ucn,
however, has more potent coronary vasodilatory and cardiac inotropic
effects in sheep than does CRF (25). In addition, CRF R2-deficient mice
have a dramatically attenuated vascular response to Ucn injection (26).
Together, these findings support the proposal that Ucn may be a natural
ligand for CRF R2 in the periphery (8, 14).
Increasing evidence suggests that both CRF R1 and CRF R2 in the brain
and pituitary play major roles in modulating adaptive responses to
stresses (8). The levels of CRF R2 and CRF R1 mRNA expression are
altered in the hypothalamus after exposure to stressors (27, 28, 29). The
responses of peripheral CRF receptors to stress, however, are not
completely understood. In a previous study expression levels of CRF R2
mRNA in the heart were decreased after exposure to the immune challenge
of lipopolysaccharide (LPS) (30). After immune stimulation, tumor
necrosis factor- (TNF), interleukin-1 (IL-1), and IL-6 are known
to be elevated in the systemic circulation. These cytokines also
increase the activity of the hypothalamus-pituitary-adrenal (HPA) axis,
resulting in the release of additional ACTH and corticosterone (31, 32). Injection of deoxycorticosterone also reduces the expression
levels of CRF R2ß mRNA (33). It is not known, however, whether
cytokines themselves modulate CRF R2ß mRNA expression, nor is it
known whether changes in endogenous corticosterone levels are capable
of regulating CRF R2ß mRNA expression.
In the present study we extended observations on stress- or hormone-induced changes in CRF R2ß mRNA expression in the cardiovascular system and examined possible mediators for changes in CRF R2ß mRNA levels. In vivo, we tested the hypothesis that the expression levels of CRF R2ß mRNA in the heart would be altered by HPA stimulation after both immune and nonimmune stress. To assess potential factors responsible for the changes in CRF R2ß mRNA levels, we chose an in vitro approach. Currently, the cell line A7R5, an aortic smooth muscle cell line, is available. We determined the effects of CRF, Ucn, glucocorticoids, and cytokines on CRF R2ß mRNA expression levels in the A7R5 cell line.
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Materials and Methods |
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Surgery
Jugular vein cannulation. In all rats, a jugular vein
catheter (PE 50, Becton Dickinson and Co., Sparks, MD) was
inserted into the right atrium under light halothane anesthesia 2 days
before experiments. The catheter was filled with sterile heparinized
saline, passed through a sc tunnel, and exteriorized at the back of the
neck. After the cannulation, rats were housed in individual cages.
Subcutaneous cannulation. In animals in which ACTH gel or corticosterone was injected, a sc catheter (PE 20, Becton Dickinson and Co.) was inserted into the back at the same time as jugular vein cannulation. The catheter was filled with saline, passed through a sc tunnel, and exteriorized at the back of the neck.
Adrenalectomy (Adx). Halothane-anesthetized rats were bilaterally Adx via a dorsal approach and sc implanted with a slow release corticosterone pellet (35 mg, 21-day release; Innovative Research of America, Sarasota, FL; Adx + corticosterone). This regimen was chosen for its ability to retain basal CRF and vasopressin mRNA levels in the paraventricular nucleus of the hypothalamus and POMC mRNA levels in the anterior pituitary after Adx (34). A control group of rats (sham) was anesthetized, received the same dorsal incision, and was implanted with a placebo pellet. After surgery, all rats were provided with water containing 0.9% NaCl. Five days later, sham and Adx + corticosterone rats participated in LPS experiments. In LPS-injected Adx + corticosterone rats, Adx was verified by the lack of change in plasma corticosterone. In saline-injected Adx + corticosterone rats, Adx was verified by the lack of circadian elevation in plasma corticosterone 8 h after lights on.
Reagents
LPS (Escherichia coli serotype O26: B6; code 3755,
lot 37H4095) and corticosterone were purchased from Sigma
(St. Louis, MO). ACTH gel (H.P. Acthar gel) was purchased from
Rhone-Poulenc Rorer Pharmaceuticals, Inc. (Collegeville, PA).
In vivo experimental procedure
On the day of the experiment, the rats were housed in opaque
sampling cages, and the jugular vein catheter was connected to a
sampling tube to allow for remote sequential blood sampling. After a
period of 2–3 h, experiments were started at 0800–0900 h. The rats
were killed by decapitation after final blood sampling. The whole
hearts and the aorta (arch of aorta and thoracic aorta) were removed
and frozen in liquid nitrogen.
Exp 1: effects of iv injection of LPS (50 µg/kg BW) on CRF R2ß mRNA levels in the heart. After blood sampling for measurement of basal plasma ACTH and corticosterone levels, vehicle (saline, 100 µl) or LPS at a dose of 50 µg/kg BW was injected iv at 0 min. Blood was drawn 30, 60, 120, 240, and 360 min later and stored for future measurements of plasma ACTH and corticosterone. After sampling blood at 6 h, some rats were decapitated, and organs were harvested. To examine time-dependent changes in CRF R2ß mRNA levels, other rats were decapitated 2, 9, and 24 h after vehicle or LPS injection.
Exp 2: effects of sc injection of ACTH gel (0.8 U/animal) on CRF R2ß mRNA levels in the heart. After blood sampling for measurement of basal plasma corticosterone levels (0 min), vehicle (saline, 100 µl), LPS (50 µg/kg BW, iv), or ACTH gel (0.8 U/rat, sc) was injected. ACTH was also administered at 30 and 60 min. This dose regimen was chosen to ensure a prolonged endogenous corticosterone release (35). Blood was drawn 30, 60, 120, 180, 240, 300, and 360 min after LPS injection or first ACTH injection for plasma corticosterone measurement. After sampling at 6 h, the rats were decapitated for tissue collection.
Exp 3: effects of Adx with corticosterone replacement and LPS injection (50 µg/kg BW) on CRF R2ß and Ucn mRNA levels in the heart. After blood sampling for measurement of the basal plasma ACTH and corticosterone levels, vehicle (saline, 100 µl) or LPS (50 µg/kg BW, iv) was injected at 0 min in sham or Adx + corticosterone rats. Blood was drawn at 60 and 240 min for ACTH and corticosterone measurements. After the final blood sampling, the rats were decapitated for tissue collection.
Exp 4: effects of sc injection of corticosterone or restraint stress on CRF R2ß and Ucn mRNA levels in the heart or the aorta. After blood sampling for measurement of the basal plasma ACTH and corticosterone levels, vehicle (100 µl saline for iv injection and 200 µl 11% ethanol-containing saline for sc injection), LPS (50 µg/kg BW, iv), a low dose of corticosterone (37.5 µg/rat, sc), or a high dose of corticosterone (125 µg/rat, sc) was injected. Both low and high doses of corticosterone were also administered at 30, 60, 120, and 180 min. Some rats that received both vehicle injections were wrapped in cloth towels and restrained by rubber bands and labeling tape for 1 h. Blood was drawn 30, 60, 180, and 360 min after injection or onset of restraint for plasma ACTH and corticosterone measurements. After sampling at 6 h, the rats were decapitated for tissue collection.
Corticosterone and ACTH measurements
Plasma corticosterone and ACTH were measured in duplicate from
unextracted samples; these data have been reported previously (16).
Plasma corticosterone levels were measured with a commercial
immunoradiometric assay kit produced by ICN Biomedicals, Inc. (Costa Mesa, CA). Plasma ACTH levels were measured with a
commercial immunoradiometric assay kit produced by Nichols Institute Diagnostics (San Juan Capistrano, CA). Samples
repeated from individual rats were analyzed within the same assay.
Cell culture
The aortic smooth muscle cell line, A7R5, was obtained from
American Type Culture Collection (Manassas, VA). Rat Ucn
and rat/human CRF were synthesized and provided by Dr. J. Rivier (The
Salk Institute, La Jolla, CA). Recombinant rat IL-1ß, IL-6, and
TNF purchased from Endogen, Inc. (Woburn, MA).
Water-soluble dexamethasone was purchased from Sigma. The
A7R5 cells were incubated at 37 C in a humidified atmosphere of 5%
CO2 and 95% air and in DMEM supplemented with
10% FBS, 2 mM L-glutamine, 100 µg/ml
streptomycin, and 100 U/ml penicillin. Cells were initially plated at
104 cells/cm2 7 days before
each experiment. The medium was changed every 48 h. On the sixth
day, cells were washed and starved overnight with DMEM supplemented
with 0.2% FBS. On the seventh day, the cells were treated for each
experiment. All treatments were performed in triplicate and repeated
three times.
Ribonuclease (RNase) protection
Total RNA was extracted using Tri-Reagent (Molecular Research Center, Inc., Cincinnati, OH).
Rat Ucn or CRF R2ß, and glyceraldehyde-3-phosphate dehydrogenase
(GAPDH) mRNA levels were measured simultaneously by RNase protection,
using rat GAPDH as an internal loading control. A 361-nucleotide (nt)
Ucn antisense riboprobe specific to the rat Ucn mRNA and a 294-nt CRF
R2ß antisense riboprobe specific to the rat CRF R2ß mRNA were
synthesized using T7 and T3 RNA polymerase, respectively. A 165-nt
GAPDH antisense riboprobe specific to the rat GAPDH mRNA was
synthesized using T3 RNA polymerase. All riboprobes were synthesized in
the presence of [-32P]UTP (3000 Ci/mmol) and
20 µM UTP, as previously described (36). The fragments
protected by the Ucn, CRF R2ß, and GAPDH riboprobes were 307, 166,
and 135, respectively (Fig. 1
).
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Statistical analysis
All values are expressed as the mean ± SEM.
Statistical analyses of these data were performed using one-way ANOVA
or two-way ANOVA on repeated measures, with time and treatment as the
factors (followed by Scheffé’s F post-hoc test).
P < 0.05 was accepted as statistically
significant.
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). CRF R2ß mRNA was
expressed in rat heart, aorta, and A7R5 aortic smooth muscle cells. By
contrast, Ucn mRNA was detected in the heart, and not in the aorta. Ucn
mRNA was not found in the A7R5 cell line (not shown).
Effects of LPS on CRF R2ß mRNA levels in the heart
Rats were iv injected with saline or LPS (50 µg/kg), and plasma
ACTH and corticosterone levels were measured. As previously reported
(16), plasma ACTH and corticosterone levels immediately before
treatment in both saline- and LPS-treated groups were typical of those
in rats under nonstress conditions. Levels in saline-injected rats
demonstrated the expected diurnal variations. Intravenous
administration of LPS elicited time-dependent increases in plasma ACTH
and corticosterone levels, with peak concentrations measured 1 h
(mean ± SEM, 820.42 ± 115.73 pg/ml) and 2
h (mean ± SEM, 522.61 ± 137.34 ng/ml) after
injection, respectively.
Figure 2 shows significant time-dependent
changes in heart CRF R2ß mRNA levels after iv injection of LPS
(P < 0.0001, by ANOVA). CRF R2ß mRNA levels were
decreased to less than half those of the control values by 6 h
after LPS injection (P < 0.0001). Subsequently, CRF
R2ß mRNA levels in the heart were still significantly decreased
9 h (P < 0.01) after the injection, but tended to
return toward control levels 24 h after the injection.
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The levels of CRF R2ß mRNA in the heart were significantly decreased
6 h after ACTH injection as well as after LPS treatment to levels
approximately half those measured in saline-injected rats (Fig. 3). The decrease in CRF R2ß mRNA levels
seen after the injection of ACTH was not significantly different from
that observed after LPS injection.
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There was a significant interaction between adrenal surgery and
treatment on CRF R2ß mRNA levels (P < 0.05, by
ANOVA; Fig. 4A). As in the experiments
detailed above, CRF R2ß mRNA levels in the heart decreased by half
after LPS injection in sham rats (P < 0.001). Adx +
corticosterone attenuated the effects of LPS injection on CRF R2ß
mRNA levels in the heart compared with those in LPS-injected sham rats
(P < 0.05). This reversal, however, was not complete;
CRF R2ß mRNA levels after LPS injection in Adx + corticosterone rats
were less than those in control sham rats (P < 0.05).
This suggests that other factors in addition to corticosterone may
have been involved in the regulation of CRF R2ß mRNA expression after
immune challenge. There was no significant effect of LPS injection or
Adx on Ucn mRNA levels in the heart (Fig. 4B).
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Figure 5 demonstrates the effects of LPS,
corticosterone, and restraint on CRF R2ß and Ucn mRNA levels in the
heart and aorta (P < 0.001, by ANOVA). CRF R2ß mRNA
levels in the heart and aorta were significantly decreased after LPS
injection, high dose corticosterone injection, and restraint. Ucn mRNA
levels in the heart were not significantly changed after LPS injection,
low dose corticosterone, or restraint. By contrast, Ucn mRNA levels
doubled 6 h after the injection of the high dose of corticosterone
(P < 0.05) compared with those in saline-injected
rats.
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shows significant time-
and dose-dependent changes in CRF R2ß mRNA levels after dexamethasone
administration (P < 0.001, by ANOVA). Incubation with
0.2 µM dexamethasone decreased CRF R2ß mRNA
levels 6 and 24 h, but not 2 h, after treatment (Fig. 6, A
and B, demonstrates the effects of increasing concentrations of
dexamethasone administration for 6 h on CRFR2ß mRNA levels).
Concentrations of dexamethasone ranging from 0.02–20
µM produced a significant dose-dependent
decrease in CRF R2ß mRNA levels.
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) suggested that factors
other than corticosterone regulate CRF R2ß mRNA levels in
vivo. We examined the regulation of CRF R2ß mRNA levels by CRF
R2ß ligands and cytokines in A7R5 cells. As in shown Fig. 7A, the peak decrease in CRF R2ß mRNA
levels occurred 6 h after incubation with either CRF (1
µM) or Ucn (10 nM).
Subsequently, the decrease in CRF R2ß mRNA levels by Ucn
administration was shown to be dose dependent, with a maximal effect
reached at 10 nM (P < 0.0001;
Fig. 7B). Ucn was more potent than CRF in decreasing CRF R2ß mRNA
levels (Fig. 7B).
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on CRF R2ß mRNA levels in
A7R5 aortic smooth muscle cells are well known as proinflammatory
factors that are induced by endotoxin. These proteins also contribute
to HPA axis activation after immune challenge. The decreases in CRF
R2ß mRNA concentrations measured after LPS injection in
vivo were not entirely dependent on elevations of circulating
corticosterone; therefore, we hypothesized that cytokines might have a
role in regulating CRF R2ß mRNA levels during immune challenge. The
cells were cultured for 6 h in the presence of IL-1ß, IL-6, or
TNF (500 pM). As shown in Fig. 8, CRF R2ß mRNA levels were
significantly decreased 6 h after each of these treatments (IL-1
and TNF, P < 0.001; IL-6, P <
0.01). The administration of IL-1ß caused a dose-dependent decrease
in CRF R2ß mRNA levels that achieved statistical significance at 5
pM (P = 0.0013). A considerable
decrease of approximately 47% in CRF R2ß mRNA levels was observed at
the maximal concentration of IL-1ß.
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It is also possible that decreased CRF R2ß mRNA expression after corticosterone or dexamethasone administration in vivo is partly due to changes in vascular tone. CRF R2 mRNA levels in the heart of spontaneously hypertensive rats were reported to be higher than those in normotensive rats (33), supporting the idea that vascular tone modulates CRF R2 mRNA expression. Glucocorticoids have been postulated to inhibit the production of nitric oxide, a potent vasodilator, in vascular smooth muscle cells (38). Glucocorticoids, therefore, could potentially modulate the vasodilatatory response to stress through changes in nitric oxide production both in vivo and in vitro. It does not appear, however, that acute changes in blood pressure alone are responsible for decreased CRF R2ß mRNA expression levels. LPS injection eventually decreases blood pressure (39), whereas restraint stress increases blood pressure (40). As both treatments reduce CRF R2ß mRNA levels, it is unlikely that changes in vascular tone alone account for changes in gene expression.
LPS injection in vivo increases circulating levels of
several classes of cytokines (32). We observed that in A7R5 cells, the
proinflammatory cytokines, IL-1ß, TNF, and IL-6, each decreased
CRF R2ß messenger levels, with IL-1ß being the most effective at
the doses tested. Therefore, after immune challenges, increased
circulating concentrations of some cytokines might regulate CRF R2ß
mRNA levels in vivo (41). It is known that IL-1ß
contributes to the down-regulation of CRF R1 in the rat pituitary (42),
suggesting that similar upstream elements for this cytokine signaling
in the promoter between CRF R1 and CRF R2 may regulate the expression
of these CRF receptors (43). The fact that these three cytokines
modulate CRF R2ß gene expression levels suggests that there is a
profound redundancy via the proinflammatory signal transduction system,
because both TNF and IL-1 activate cell signaling via the same nuclear
factor-
B pathway (44), whereas IL-6 acts through the Janus
kinase/signal transducer and activator of transcription/suppression of
cytokine signaling pathways (45). In addition, LPS may act
directly via CD14/TLR4/nuclear factor-B pathway (46).
It is of interest to note that preventing the LPS-induced increase in circulating corticosterone concentrations via Adx + corticosterone replacement only partially inhibited the decrease in CRF R2ß mRNA expression in the heart. This observation coupled with the effects of cytokines on CRF R2ß mRNA expression in A7R5 cells suggests that each factor or LPS itself may be involved in the decrease in CRF R2ß mRNA expression after immune challenge.
Our in vitro study showed that Ucn or CRF administration to A7R5 cells decreased CRF R2ß mRNA levels, consistent with the possibility that a ligand for CRF R2ß may be involved in the regulation of CRF R2ß mRNA expression in vivo during stress either directly or through the production of additional factors. If this is the case, it is not clear which endogenous ligands activate CRF R2 in the heart, when local concentrations of ligands rise in the heart and what the source of those ligands might be. Both CRF and Ucn mRNA are found in cardiac tissues (16, 22, 47). Prior studies show that Ucn has far higher affinity for CRF R2 than does CRF (14); furthermore, Ucn has more potent cardiac inotropic effects than does CRF (25). In the present study Ucn was more potent than CRF at decreasing CRF R2ß mRNA levels, in keeping with the hypothesis that CRF R2ß stimulation mediates down-regulation of itself. It is unclear, however, whether any locally produced Ucn normally regulates CRF R2ß mRNA levels in the heart and aorta in vivo. It is also possible that CRF R2ß in the heart and aorta may be stimulated by circulating Ucn (17).
In the present study the levels of Ucn mRNA in the heart were significantly increased after high doses of corticosterone injection, but not low doses of corticosterone or LPS injection. These results are different from those in the thymus, in which both LPS and corticosterone increased Ucn mRNA levels (16). In both of these tissues, there are relatively high concentrations of glucocorticoid receptors (48); therefore, the expression levels of Ucn mRNA in the heart and thymus may be stimulated directly by glucocorticoids. The susceptibility to proinflammatory factors might be different among the tissues. Alternatively, the regulation of Ucn mRNA expression in the heart may be controlled by multiple factors, some of which may counter corticosterone-induced increases.
The biological significance of changes in CRF R2ß mRNA levels in the cardiovascular system remains to be elucidated. In the anterior pituitary, a ligand-induced reduction in CRF-binding sites (49, 50) is achieved through both internalization of receptors (51) and suppression of new receptor synthesis (52). It is possible that the decrease in CRF R2ß mRNA levels in the cardiovascular system after stress contributes to a reduction in the number of ligand-binding sites, restricting subsequent ligand-mediated activity.
Ucn stimulates potent coronary vasodilatory and cardiac inotropic actions via CRF R2ß (53). Our results, therefore, suggest that these decreases in CRF R2ß mRNA levels by Ucn, glucocorticoids, and cytokines could limit the time course of Ucn-induced cardiovascular effects during prolonged stress, thus contributing to the restoration of homeostasis. The redundant effects of glucocorticoids, receptor ligands, and cytokines suggest that the regulation of CRF R2ß parallels that of CRF R1. Combined CRF and vasopressin administration in rat anterior pituitary cultures decreases CRF R1 mRNA levels synergistically (54). Furthermore, some elements may influence the production of other regulators. For instance, in A7R5 cell culture, we have shown that Ucn induces IL-6 secretion (Gaudriault, G. E., and W. W. Vale, unpublished observations). Thus, decreases in CRF R2ß mRNA expression measured after Ucn administration may occur indirectly through the actions of induced cytokines. The nature of the pharmacological interactions of these separate regulators of CRF R2ß has yet to be defined in vitro in A7R5 cells.
In summary, our present data demonstrate that the aorta expresses high
levels of CRF R2ß mRNA, and the heart expresses both CRF R2ß and
Ucn mRNA. Increased concentrations of circulating glucocorticoids from
either exogenous administration or after HPA activation appear to
decrease CRF R2ß mRNA expression levels in the cardiovascular system.
It is possible that increased Ucn secretion within the heart
contributes to the regulation of CRF R2ß mRNA levels during stress.
LPS itself or IL-1ß, IL-6, and TNF produced after immune challenge
may also collaborate to suppress CRF R2ß mRNA levels in this system.
These results indicate that regulation of CRF R2ß mRNA levels by
these factors could serve to limit the cardiovascular effects of Ucn
during stress or immune challenge.
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Acknowledgments |
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Footnotes |
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2 Foundation for Research Senior Investigator.
Received January 14, 2000.
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References |
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receptor.
Mol Endocrinol 12:1077–1085 and CRF2ß receptor mRNAs are differentially distributed
between the rat central nervous system and peripheral tissues.
Endocrinology 136:4139–4142[Abstract]
in the rat. Neuroimmunomodul 2:137–140
and IL-1ß on
haemodynamic responses to the cytokines, and to lipopolysaccharide, in
conscious rats. Br J Pharmacol 125:1543–1550[CrossRef][Medline]
downregulate corticotropin-releasing hormone
receptor-2 levels in the heart. 81th Annual Meeting of The Endocrine
Society, San Diego, CA, 1999, p 320 (Abstract)
B activity by mPLK/IRAK. J Biol Chem 274:13077–13084This article has been cited by other articles:
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S. C. Coste, K. A. Heldwein, S. L. Stevens, E. Tobar-Dupres, and M. P. Stenzel-Poore IL-1{alpha} and TNF{alpha} Down-Regulate CRH Receptor-2 mRNA Expression in the Mouse Heart Endocrinology, August 1, 2001; 142(8): 3537 - 3545. [Abstract] [Full Text] [PDF]
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 K. Lewis, C. Li, M. H. Perrin, A. Blount, K. Kunitake, C. Donaldson, J. Vaughan, T. M. Reyes, J. Gulyas, W. Fischer, et al. Identification of urocortin III, an additional member of the corticotropin-releasing factor (CRF) family with high affinity for the CRF2 receptor PNAS, June 19, 2001; 98(13): 7570 - 7575. [Abstract] [Full Text] [PDF]
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