Functional genomics of the rat neuromedin U receptor 1 reveals a naturally occurring deleterious allele

2013 ◽  
Vol 45 (2) ◽  
pp. 89-97 ◽  
Author(s):  
Rosemarie Panetta ◽  
Luc Meury ◽  
Chang Qing Cao ◽  
Carole Puma ◽  
Françoise Mennicken ◽  
...  
Keyword(s):  
Functional Genomics ◽  
Radioligand Binding ◽  
Physiological Role ◽  
Nociceptive Response ◽  
Sprague Dawley ◽  
Coding Region ◽  
Binding Studies ◽  
Naturally Occurring ◽  
Sprague Dawley Rats ◽  
Toxicological Studies

Neuromedin U (NMU) plays an important role in a number of physiological processes, but the relative contribution of its two known receptors, NMUR1 and NMUR2, is still poorly understood. Here we report the existence of a SNP T1022→A (Val341→Glu) in the third exon of the rat Nmur1 gene that leads to an inactive receptor. This SNP is present within the coding region of the highly conserved NPXXY motif found within all class A type G protein-coupled receptors and translates to an NMUR1 receptor that is not expressed on the cell surface. Genetic analysis of the Nmur1 gene in a population of Sprague-Dawley rats revealed that this strain is highly heterogeneous for the inactivating polymorphism. The loss of functional NMUR1 receptors in Sprague-Dawley rats homozygous for the inactive allele was confirmed by radioligand binding studies on native tissue expressing NMUR1. The physiological relevance of this functional genomics finding was examined in two nociceptive response models. The pronociceptive effects of NMU were abolished in rats lacking functional NMUR1 receptors. The existence of naturally occurring NMUR1-deficient rats provides a novel and powerful tool to investigate the physiological role of NMU and its receptors. Furthermore, it highlights the importance of verifying the NMUR1 single nucleotide polymorphism status for rats used in physiological, pharmacological or toxicological studies conducted with NMUR1 modulators.

Adrenomedullin microinjection into the area postrema increases blood pressure

1997 ◽  
Vol 272 (6) ◽  
pp. R1698-R1703 ◽  
Author(s):  
M. A. Allen ◽  
P. M. Smith ◽  
A. V. Ferguson
Keyword(s):  
Blood Pressure ◽  
Area Postrema ◽  
Area Under The Curve ◽  
Physiological Role ◽  
Cardiovascular Responses ◽  
Hypotensive Effect ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Brain Site

Adrenomedullin (ADM) circulates in the blood at concentrations comparable to other vasoactive peptides with established roles in cardiovascular regulation. Intravenously administered ADM produces a clear hypotensive effect, whereas intracerebroventricular microinjections result in increases in blood pressure (BP). Recently, we demonstrated that ADM influences neurons of the area postrema (AP), a central nervous system site implicated in cardiovascular control. However, to address directly the physiological significance of the actions of ADM at the AP, an in vivo microinjection study was undertaken. ADM, at two concentrations (1 and 10 microM), in volumes of 50, 100, and 200 nl, was microinjected into the AP or NTS of 21 urethan-anesthetized male Sprague-Dawley rats. Microinjection of 10 microM ADM (100 nl) resulted in significant transient (2-5 min) increases in BP [120 s area under the curve (AUC): 684.3 +/- 268.6 mmHg/s (P < 0.05)], and heart rate (HR) [AUC: 12.5 +/- 4.5 beats/min (P < 0.05)]. The lower concentration of ADM (1 microM) had no effect on either BP (179.1 +/- 143.6 mmHg/s) or HR (0.8 +/- 2.6 beats/min). ADM was also microinjected into the immediately adjacent nucleus of the solitary tract, where it was found to be without effect on either BP or HR. This study demonstrates, for the first time, a physiological role for ADM acting at a specific brain site, the AP, to produce significant cardiovascular responses.

scholarly journals Evidence that natural murine soluble interleukin 4 receptors may act as transport proteins.

1991 ◽  
Vol 174 (3) ◽  
pp. 673-681 ◽  
Author(s):  
R Fernandez-Botran ◽  
E S Vitetta
Keyword(s):  
Biological Fluids ◽  
Physiological Role ◽  
Receptor Internalization ◽  
Interleukin 4 ◽  
Binding Studies ◽  
Temperature Dependent ◽  
Dissociation Kinetics ◽  
Naturally Occurring ◽  
Peptide Maps

The present studies were undertaken to determine whether the interleukin 4 binding proteins (IL-4BPs) previously identified in the biological fluids of mice are soluble forms of IL-4Rs. We also studied the binding properties of IL-4BPs in order to gain insight into their physiological role in vivo. Affinity-purified IL-4BPs and recombinant soluble IL-4Rs generated similar one-dimensional (Cleveland) peptide maps after digestion with either Staphylococcus aureus V8 protease or trypsin, indicating structural similarities. Furthermore, a rat mAb directed against the murine IL-4Rs immunoprecipitated the IL-4BPs and completely inhibited binding of 125I-IL-4 to a purified preparation of IL-4BPs. Taken together these data indicate that the IL-4BPs are soluble IL-4Rs. At 4 degrees C the IL-4BPs competitively inhibited the binding of IL-4 to membrane IL-4Rs but their ability to prevent binding of IL-4 to cells at 37 degrees C, at the same concentrations, was significantly reduced. Kinetic binding studies of soluble IL-4BPs vs. membrane IL-4Rs disclosed important differences in their rates of dissociation from IL-4. Whereas dissociation at 4 degrees C was slow for both, dissociation of IL-4 from IL-BPs at 37 degrees C was considerably faster (t 1/2 of 2 min) than dissociation of IL-4 from membrane IL-4Rs (t 1/2 of approximately 69 min). Temperature-dependent changes in dissociation kinetics were reversible, and could not be accounted for by either inactivation of the IL-4BPs at 37 degrees C or receptor internalization. Additional experiments also demonstrated that when IL-4BPs bind to IL-4 at 37 degrees C, the IL-4/IL-4BPs complex can rapidly dissociate, allowing IL-4 to bind to membrane IL-4Rs. In addition, binding of IL-4 by the IL-4BPs protects IL-4 from proteolytic degradation. Taken together, these results suggest that the IL-4BPs are naturally occurring forms of soluble IL-4Rs and that some of their properties (fast dissociation kinetics and protection of IL-4 from proteolysis) are consistent with a potential role as carrier proteins for IL-4 in the circulation.

Abstract P616: Evidence That The Extracellular Domain Of Na + /K + Atpase Is The Receptor For Cyclic Gmp-Induced Natriuresis

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Brandon A Kemp ◽  
John J Gildea ◽  
Nancy L Howell ◽  
Susanna R Keller ◽  
Robert M Carey
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Control Period ◽  
Extracellular Domain ◽  
Sprague Dawley ◽  
Binding Studies ◽  
Urine Sodium ◽  
Sprague Dawley Rats ◽  
Normal Rat ◽  
Change In Mean

Previous studies from our laboratory have shown that extracellular renal interstitial (RI) cyclic guanosine 3’5’-monophosphate (cGMP) increases urine sodium (Na + ) excretion (U Na V) at the renal proximal tubule (RPT) in rats via activation of Src family kinase. Extracellular cGMP engenders this response through an unknown receptor. We hypothesized that cGMP binds to the extracellular domain of Na + /K + -ATPase (NKA) on basolateral membranes of RPT cells inhibiting Na + transport. In the present study, we evaluated the effect of RI infusion of rostafuroxin (RF), a digitoxigenin derivative that specifically displaces oubain (OUA) binding from NKA, on U Na V in the presence of RI cGMP infusion. Volume expanded, uninephrectomized, 12-week-old female Sprague-Dawley rats received RI infusions of vehicle (D 5 W) (N=8), RI cGMP (18, 36, and 72 μg/kg/min; each dose for 30 min; N=10), or RI cGMP + RF (0.012 μg/kg/min; N=5) for 90 min following a 30 min control period with RI infusion of vehicle D 5 W. RI cGMP infusion induced a significant natriuresis from 0.39 ± 0.06 μmol/min to 1.03 ± 0.21 (P<0.05), 1.17 ± 0.19 (P<0.01), and 1.94 ± 0.16 (P<0.001) μmol/min at 18, 36, and 72 μg/kg/min cGMP, respectively. RI co-infusion of cGMP + RF abolished the cGMP-induced natriuresis at all doses (F=16.05, P<0.001). There was no change in mean arterial pressure during any infusion. To further demonstrate that cGMP binds to NKA, we performed a series of competitive binding studies in isolated RPTs from normal rat kidneys (N=4 for each) with bodipy-OUA (2 μM) + cGMP (10 μM) and 8-[Biotin]-AET-cGMP (2 μM) + OUA (10 μM). In the presence of cGMP, bodipy-OUA fluorescence intensity was reduced from 1422.1 ± 63 to 1072.5 ± 64 relative fluorescent units (RFU, P<0.01). In the presence of OUA, 8-[Biotin]-AET-cGMP staining was reduced from 1916.3 ± 144 to 1492.2 ± 84 RFU (P<0.05). Serving as control, biotinylated cAMP (N=2) did not demonstrate any fluorescence above background. Together, these data suggest that cGMP may compete with RF for binding on NKA and that the extracellular domain of NKA may serve as the receptor for cGMP-induced natriuresis.

Altered cardiovascular regulation in arginine vasopressin-overexpressing transgenic rat

2003 ◽  
Vol 285 (6) ◽  
pp. E1161-E1166 ◽  
Author(s):  
Kazushige Tachikawa ◽  
Hisashi Yokoi ◽  
Hiroshi Nagasaki ◽  
Hiroshi Arima ◽  
Takashi Murase ◽  
...  
Keyword(s):  
Arginine Vasopressin ◽  
Physiological Role ◽  
Cardiovascular Regulation ◽  
High Plasma ◽  
Transgenic Rat ◽  
Sprague Dawley ◽  
Induced Hypotension ◽  
Arterial Blood ◽  
Sprague Dawley Rats ◽  
And Control

Although arginine vasopressin (AVP), an antidiuretic hormone, has been widely acknowledged to play an important role in cardiovascular regulation via V1a receptors (V1aR), its precise significance remains unclear. In this study, we investigated the effects of long-standing high plasma AVP status on cardiovascular regulation in the AVP-overexpressing transgenic (Tg) rat. Adult male homozygous Tg rats were compared with age-matched normal Sprague-Dawley rats as controls. There were no significant differences in mean arterial blood pressure (BP; MABP) or heart rate between Tg and control rats in the basal state. Subcutaneous injection of AVP significantly increased MABP in controls but did not cause any apparent increase in MABP in Tg rats. BP recovery from hemorrhage-induced hypotension was significantly delayed in Tg compared with control rats. Pretreatment with a selective V1aR antagonist, OPC-21268, which is thought to restore the downregulation of V1aR, markedly improved both of these impaired responses. Northern blot analysis confirmed that decreased expression of V1aR mRNA and pretreatment with V1aR antagonist significantly restored the downregulation of V1aR mRNA. These results suggest that the Tg rat has decreased sensitivity to the hypertensive effect of AVP due to downregulation of V1aR, which may function as an adaptive mechanism to maintain normal BP against chronic hypervasopressinemia. In addition, impaired restoration of BP after hemorrhage-induced hypotension in Tg rats supports a physiological role of AVP in cardiovascular regulation.

Inhibition of drinking in water-deprived rats by combined central angiotensin II and cholinergic receptor blockade

1978 ◽  
Vol 234 (1) ◽  
pp. F41-F47 ◽  
Author(s):  
W. E. Hoffman ◽  
U. Ganten ◽  
M. I. Phillips ◽  
P. G. Schmid ◽  
P. Schelling ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Water Intake ◽  
Physiological Role ◽  
Cholinergic Receptor ◽  
Inhibitory Effect ◽  
Cholinergic Receptors ◽  
Sprague Dawley ◽  
Cholinergic Blockade ◽  
Sprague Dawley Rats ◽  
Hereditary Hypothalamic Diabetes Insipidus

The effect of blockade of central angiotensin II (AII) receptors and cholinergic receptors on thirst induced by water deprivation was studied in Sprague-Dawley rats and rats with hereditary hypothalamic diabetes insipidus (DI). Neither central AII nor cholinergic blockade alone affected drinking. Antagonism of both receptors simultaneously, however, significantly inhibited water intake of both Sprague-Dawley and DI rats. This inhibitory effect was not observed in water-deprived, nephrectomized rats. The combined antagonism on water intake was specific, since milk intake in hungry rats was not affected by simultaneous AII and cholinergic blockade. Isorenin concentrations in brain tissue were at control levels in water-deprived, nephrectomized, and non-nephrectomized Sprague-Dawley rats but were increased in water-deprived DI rats. The results suggest that angiotensin and cholinergic receptors in the brain have a physiological role in thirst. Thirst is maintained when either receptor is intact, but reduced when both receptors are inhibited by antagonists. They are independently capable of maintaining thirst.

Hepatic portal infusion of glucagon antibodies increases spontaneous meal size in rats

1991 ◽  
Vol 261 (1) ◽  
pp. R162-R165 ◽  
Author(s):  
J. Le Sauter ◽  
U. Noh ◽  
N. Geary
Keyword(s):  
Physiological Role ◽  
Meal Size ◽  
Dark Phase ◽  
Sprague Dawley ◽  
Nocturnal Feeding ◽  
Sprague Dawley Rats ◽  
Ad Libitum ◽  
Hepatic Portal ◽  
Portal Infusion

Specific antibodies to pancreatic glucagon in a dose sufficient to neutralize 1.5 ng glucagon in vitro were intraportally infused during the first 2 min of spontaneous meals in ad libitum-fed male Sprague-Dawley rats. In separate tests, glucagon antibodies stimulated feeding during the first spontaneous meal of the dark phase (73% mean increase in meal size) and during spontaneous meals in the last quarter of the dark phase (58% increase). These results indicate that a glucagon-sensitive satiety mechanism has a physiological role in the control of nocturnal feeding in rats.

EFFECT OF CATECHOL OESTROGENS ON INDUCED OVULATION IN THE IMMATURE RAT

1980 ◽  
Vol 86 (2) ◽  
pp. 263-268 ◽  
Author(s):  
S. FRANKS ◽  
P. BALL ◽  
F. NAFTOLIN ◽  
K. B. RUF
Keyword(s):  
Positive Feedback ◽  
Physiological Role ◽  
Fallopian Tubes ◽  
Minimum Effective Dose ◽  
Sprague Dawley ◽  
Immature Rat ◽  
Induced Ovulation ◽  
Sprague Dawley Rats ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Positive Feedback Effect

The 'positive feedback' effect of exogenous oestradiol-17β in advancing ovulation induced by pregnant mare serum gonadotrophin (PMSG) has been used in the present study as a model in which to test the possible oestrogenic or antioestrogenic effects of the catechol oestrogens, 2-hydroxyoestradiol (2-OHE2) and 4-OHE2. Sprague–Dawley rats of 26 days of age were injected with 20 i.u. PMSG together with either vehicle alone or test steroids. The animals were killed 72 h later and the Fallopian tubes were examined for the presence of ova. Advancement of induced ovulation by treatment with oestradiol was confirmed; 2-OHE2, in doses of up to 100 pg, influenced neither the time of ovulation nor the number of ova present but 4-OHE2 was equipotent with oestradiol in doses varying from 0·5 pg (the minimum effective dose for both steroids) to 10 μg. The possible antioestrogenic effect of 2-OHE2 was tested by giving a 100 pg dose either at the same time or 2 h before PMSG plus 2 pg oestradiol or 4-OHE2. The effects of oestradiol and 4-OHE2 were not altered by this treatment. These data show that, in this model of'positive feedback', 2-OHE2 has neither an oestrogenic nor an antioestrogenic action but that 4-OHE2 has a potent oestrogenic action, thus raising the question of a physiological role for 4-OHE2 in the regulation of ovulation.

scholarly journals Vapor inhalation of cannabidiol (CBD) in rats

2019 ◽  
Author(s):  
Mehrak Javadi-Paydar ◽  
Kevin M. Creehan ◽  
Tony M. Kerr ◽  
Michael A. Taffe
Keyword(s):  
Wistar Rats ◽  
Temperature Response ◽  
The Body ◽  
Nociceptive Response ◽  
Preclinical Studies ◽  
Sprague Dawley ◽  
Blood Samples ◽  
Clinical Model ◽  
Sprague Dawley Rats ◽  
Female Wistar Rats

AbstractCannabidiol (CBD) is increasingly available in e-cigarette liquids and other products. CBD use has been promoted for numerous purported benefits which have not been rigorously assessed in preclinical studies. The objective of this study was to further validate an inhalation model to assess CBD effects in the rat. The primary goal was to determine plasma CBD levels after vapor inhalation and compare that with the levels observed after injection. Secondary goals were to determine if hypothermia is produced in male Sprague-Dawley rats and if CBD affects nociception measured by the warm water tail-withdrawal assay. Blood samples were collected from rats exposed for 30 minutes to vapor generated by an e-cigarette device using CBD (100, 400 mg/mL in the propylene glycol vehicle). Separate experiments assessed the body temperature response to CBD in combination with nicotine (30 mg/mL) and the anti-nociceptive response to CBD. Vapor inhalation of CBD produced concentration-related plasma CBD levels in male and female Wistar rats that were within the range of levels produced by 10 or 30 mg/kg, CBD, i.p.. Dose-related hypothermia was produced by CBD in male Sprague-Dawley rats and this was partially attenuated by 5-HT1a receptor blockade. Nicotine (30 mg/mL) inhalation enhanced the effect of CBD. CBD inhalation had no effect on anti-nociception alone or in combination with Δ9-tetrahydrocannabinol inhalation. The vapor-inhalation approach is a suitable pre-clinical model for the investigation of the effects of inhaled CBD. This route of administration produces hypothermia in rats, while i.p. injection does not at comparable plasma CBD levels.

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