Characterization of α1-adrenergic receptor subtypes linked to iodide efflux in rat FRTL cells

1990 ◽  
Vol 124 (3) ◽  
pp. 433-441 ◽  
Author(s):  
H. Shimura ◽  
T. Endo ◽  
G. Tsujimoto ◽  
K. Watanabe ◽  
K. Hashimoto ◽  
...  
Keyword(s):  
Program Analysis ◽  
Binding Sites ◽  
Adrenergic Receptor ◽  
Receptor Subtype ◽  
Receptor Subtypes ◽  
Receptor Density ◽  
Maximal Increase ◽  
Thyroid Cells ◽  
Rat Thyroid

ABSTRACT We have characterized α1-adrenergic receptor subtypes in functional rat thyroid cells, FRTL, with relation to iodide efflux, and have also examined the effect of TSH on α1 receptor subtypes. FRTL cells grown in a medium containing 5 mU TSH/ml (6H cells) had five times the number of α1 receptors of those maintained in TSH-free medium (5H cells) (11·2 fmol/106 cells compared with 2·0 fmol/106 cells). Pretreatment with chlorethylclonidine (CEC; 10 μmol/l), which inactivates only α1b receptors, caused 98·8% and 97·0% decreases in the density of specific [3H]prazosin-binding sites in 5H and 6H cells respectively. LIGAND computer program analysis of the displacement curves for 2-(2,6-dimethoxyphenoxyethyl)-aminomethyl-1,4 benzodioxane (WB4101) showed that FRTL cells contained mostly low-affinity WB4101 sites. Using the phenoxybenzamine inactivation method, we found a linear relationship between α1 receptor density and the cytosolic free Ca2+ concentration response in FRTL cells. Pre-exposure of intact FRTL cells to CEC caused a 98·7% decrease in noradrenaline-stimulated maximal increase in cytosolic free Ca2+. Also, CEC and 3,4,5-trimethoxybenzoic acid 8-(diethylamino) octyl ester (TMB-8), but not nicardipine, inhibited noradrenaline-stimulated iodine efflux. The results suggest that FRTL cells contain mostly the α1b-adrenergic receptor subtype; that the α1b receptors mediate cytosolic free Ca2+ and iodide efflux responses, and that TSH enhances these responses by increasing the α1b receptor density without affecting the post-receptor mechanism. Journal of Endocrinology (1990) 124, 433–441

Thyrotrophin increases the α1b-adrenergic receptors in rat thyroid gland in vivo

1990 ◽  
Vol 126 (2) ◽  
pp. 317-322 ◽  
Author(s):  
H. Shimura ◽  
T. Endo ◽  
T. Onaya
Keyword(s):  
Thyroid Gland ◽  
Binding Sites ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Receptor Subtypes ◽  
Cent Increase ◽  
Rat Thyroid ◽  
And Control ◽  
Rat Thyroid Gland

ABSTRACT Using chlorethylclonidine (CEC), an αlb-adrenergic receptor-selective antagonist, we characterized α1-adrenoceptor subtypes in rat thyroid gland, and investigated the effect of methimazole (MMI)-induced high TSH levels on α1 receptor subtypes and noradrenaline-induced iodide organification. The density of thyroid α1-adrenergic receptors was increased about sixfold in rats treated with MMI for 3 weeks compared with controls. Pretreatment of thyroid membrane preparations with CEC (10 μmol/l) caused an 83% decrease in specific 2-[β-(hydroxy-3-[125I]iodophenyl) ethylaminomethyl]tetralone binding sites in MMI-treated rats, but only a 43% decrease in control rats. The density of CEC-insensitive α1 receptors (α1a) was similar in MMI-treated and control rats, so MMI was shown to increase CEC-sensitive α1 receptors (α1b). Noradrenaline-stimulated iodide organification was threefold greater in MMI-treated rats than in control rats when values were expressed as a per cent increase over basal levels. Pretreatment of thyroid lobes with 10 μmol CEC/1 for 30 min caused a 66% decrease in maximal noradrenaline-induced iodide organification in MMI-treated rats, but a significantly lower decrease (49%) in control rats. These results suggest that the rat thyroid gland contains both α1a and α1b receptors, both of which mediate noradrenaline-induced iodide organification, and also that TSH enhances noradrenaline-induced iodide organification by increasing α1b receptor density. Journal of Endocrinology (1990) 126, 317–322

scholarly journals Characterization of angiotensin II receptors (binding and mRNA) in the rat thyroid gland

1998 ◽  
Vol 20 (3) ◽  
pp. 299-304 ◽  
Author(s):  
M Montiel ◽  
E Jimenez
Keyword(s):  
Plasma Membrane ◽  
Angiotensin Ii ◽  
Thyroid Gland ◽  
Binding Sites ◽  
Thyroid Tissue ◽  
Receptor Subtype ◽  
Receptor Subtypes ◽  
Ang Ii ◽  
Rat Thyroid ◽  
Rat Thyroid Gland

In this study we showed, for the first time, the existence of a moderate density of specific angiotensin II (Ang II) binding sites (Kd=3.9+/-1.7 nM and Bmax=467.2 130.0 fmol/mg protein) in plasma membrane preparations from rat thyroid gland. Reverse transcriptase/polymerase chain reactions, using primers based on the cloned AT1 and AT2 receptor subtypes, and pharmacological characterization, using the Ang II receptor subtype antagonists Losartan and PD 123319, revealed that these Ang II binding sites match with the AT1 receptor subtypes. To obtain more information on the molecular structure of this Ang II receptor, immunoblotting analyses were carried out using a polyclonal rabbit anti-AT1 antiserum. Western analysis of fresh plasma membrane preparations from thyroid tissue showed three prominent bands of approximately 60, 45 and 40 kDa which appear to be related to different degrees of glycosylation of the receptor molecule. The functional significance of the Ang II receptors in thyroid gland is currently not known. Nevertheless, since Ang II receptors play a pivotal role in the co-ordinated actions of the renin-angiotensin system (RAS), our findings support a reciprocal regulation of thyroid function by the RAS.

scholarly journals Galanin-receptor ligand M40 peptide distinguishes between putative galanin-receptor subtypes

1993 ◽  
Vol 90 (23) ◽  
pp. 11287-11291 ◽  
Author(s):  
T Bartfai ◽  
U Langel ◽  
K Bedecs ◽  
S Andell ◽  
T Land ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Binding Sites ◽  
Receptor Subtype ◽  
Receptor Subtypes ◽  
Galanin Receptor ◽  
Flexor Reflex ◽  
Receptor Ligand ◽  
Insulinoma Cells ◽  
Galanin Receptors

The galanin-receptor ligand M40 [galanin-(1-12)-Pro3-(Ala-Leu)2-Ala amide] binds with high affinity to [mono[125I]iodo-Tyr26]galanin-binding sites in hippocampal, hypothalamic, and spinal cord membranes and in membranes from Rin m5F rat insulinoma cells (IC50 = 3-15 nM). Receptor autoradiographic studies show that M40 (1 microM) displaces [mono[125I]iodo-Tyr26]galanin from binding sites in the hippocampus, hypothalamus, and spinal cord. In the brain, M40 acts as a potent galanin-receptor antagonist: M40, in doses comparable to that of galanin, antagonizes the stimulatory effects of galanin on feeding, and it blocks the galaninergic inhibition of the scopolamine-induced acetylcholine release in the ventral hippocampus in vivo. In contrast, M40 completely fails to antagonize both the galanin-mediated inhibition of the glucose-induced insulin release in isolated mouse pancreatic islets and the inhibitory effects of galanin on the forskolin-stimulated accumulation of 3',5'-cAMP in Rin m5F cells; instead M40 is a weak agonist at the galanin receptors in these two systems. M40 acts as a weak antagonist of galanin in the spinal flexor reflex model. These results suggest that at least two subtypes of the galanin receptor may exist. Hypothalamic and hippocampal galanin receptors represent a putative central galanin-receptor subtype (GL-1-receptor) that is blocked by M40. The pancreatic galanin receptor may represent another subtype (GL-2-receptor) that recognizes M40, but as a weak agonist. The galanin receptors in the spinal cord occupy an intermediate position between these two putative subtypes.

scholarly journals Characterization of cardiopulmonary function and cardiac muscarinic and adrenergic receptor density adaptation in C57BL/6 mice with chronic Trypanosoma cruzi infection

Parasitology ◽  
2006 ◽  
Vol 133 (06) ◽  
pp. 729 ◽  
Author(s):  
N. N. ROCHA ◽  
S. GARCIA ◽  
L. E. D. GIMÉNEZ ◽  
C. C. Q. HERNÁNDEZ ◽  
J. F. V. SENRA ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Adrenergic Receptor ◽  
Receptor Density ◽  
Cardiopulmonary Function ◽  
Cruzi Infection

scholarly journals Thyroid-hormone modulation of the number of β-adrenergic receptors in rat fat-cell membranes

1978 ◽  
Vol 176 (3) ◽  
pp. 1007-1010 ◽  
Author(s):  
Y Giudicelli
Keyword(s):  
Thyroid Hormone ◽  
Binding Sites ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Receptor Density ◽  
Beta Adrenergic Receptors ◽  
Fat Cell ◽  
Beta Adrenergic ◽  
Hormone Modulation ◽  
Β Adrenergic Receptors

Adipocytes from thyroidectomized rats contain 3 times less [3H]dihydroalprenolol-binding sites (beta-adrenergic receptors) than adipocytes from euthyroid animals. This alteration is not solely due to cell-size differences, but also to a thyroidectomy-induced defect in beta-adrenergic receptor density per adipocyte surface area, a defect that is furthermore corrected by tri-iodothyronine treatment.

Control of arteriovenous anastomoses in rabbit ear model of digital perfusion

1996 ◽  
Vol 271 (5) ◽  
pp. H2007-H2013
Author(s):  
D. C. Pollock ◽  
Z. Li ◽  
L. A. Koman ◽  
E. S. Gordon ◽  
T. L. Smith
Keyword(s):  
Adrenergic Receptor ◽  
Receptor Subtypes ◽  
Arteriovenous Anastomoses ◽  
Cold Intolerance ◽  
Cutaneous Microcirculation ◽  
Rabbit Ear ◽  
New Zealand White Rabbits ◽  
Initial Characterization ◽  
Hands And Feet

The arteriovenous anastomoses (AVA) of the cutaneous microcirculation of the hands and feet are fundamental determinants of thermoregulatory blood flow and may be involved in cold intolerance. These direct microvascular studies are an initial characterization of adrenergic receptor subtypes participating in control of AVA in the ears of anesthetized male New Zealand White rabbits. Adrenergic alpha 1-stimulation with phenylephrine produced AVA constriction, whereas terazosin (an alpha 1-antagonist) produced dilation and attenuated the responses to phenylephrine. Adrenergic alpha 2-stimulation with UK-14304 produced constriction of the AVA, whereas atipamezole (an alpha 2-antagonist) produced dilation and attenuated the responses to UK-14304. When equimolar concentrations of antagonists were studied, the AVA dilation produced by alpha 2-blockade was greater than that produced by alpha 1-blockade. Norepinephrine (a mixed alpha 1- and alpha 2-agonist) also produced vasoconstriction, which was attenuated by both prazosin (an alpha 1-antagonist) and atipamezole. In summary, 1) AVA contain a heterogeneous mixture of both alpha 1- and alpha 2-receptors, and 2) alpha 2-receptors may have a greater influence than alpha 1-receptors on overall tone in AVA.

Characterization of Tumor Necrosis Factor-α Receptors in Human and Rat Thyroid Cells and Regulation of the Receptors by Thyrotropin*

Endocrinology ◽  
1989 ◽  
Vol 125 (4) ◽  
pp. 1783-1788 ◽  
Author(s):  
XUAN-PING PANG ◽  
JEROME M. HERSHMAN ◽  
MATT CHUNG ◽  
A. EUGENE PEKARY
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Thyroid Cells ◽  
Rat Thyroid ◽  
Factor Α ◽  
Necrosis Factor

Impact of parainfluenza-3 virus infection on endothelin receptor density and function in guinea pig airways

2002 ◽  
Vol 103 (s2002) ◽  
pp. 345S-348S ◽  
Author(s):  
Angela C. D'APRILE ◽  
Lynette B. FERNANDES ◽  
Paul J. RIGBY ◽  
Roy G. GOLDIE
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Binding Sites ◽  
Specific Binding ◽  
Tracheal Smooth Muscle ◽  
Receptor Subtypes ◽  
Post Inoculation ◽  
Receptor Density ◽  
And Function ◽  
The Impact

We examined the impact of parainfluenza-3 (P-3) respiratory tract viral infection on the density and function of endothelin (ET) receptor subtypes (ETA and ETB) in guinea pig tracheal smooth muscle. Total specific binding of [125I]ET-1 and the relative proportions of ETA and ETB binding sites for this ligand were assessed at day 0 (control) and at 2, 4, 8 and 16 days post-inoculation. At day 0, the proportions of ETA and ETB binding sites were 30% and 70% respectively. Total specific binding was significantly reduced at day 4 post-inoculation (32% reduction, n = 8–12, P<0.05) and was largely due to a corresponding fall in ETB receptor density at this time point (38% reduction, n = 8–12, P<0.05). The density of ETA receptors also fell significantly at day 8 post-inoculation (33% reduction, n = 6–12, P<0.05). By day 16 post-inoculation, the densities of ETA and ETB receptors had recovered to control values. The ratio of ETA:ETB receptor subtypes did not alter with P-3 infection. While P-3 infection reduced the density of tracheal smooth muscle ETA and ETB receptors, the contractile sensitivity and maximum response to carbachol and ET-1 was not altered in tissue from day 4 post-inoculation compared with the control. There seems to be a significant functional reserve for both receptor subtypes in this species that buffers the impact of P-3 infection on airway smooth muscle responsiveness to ET-1.

scholarly journals Activation and Deactivation Kinetics of α2A- and α2C-Adrenergic Receptor-activated G Protein-activated Inwardly Rectifying K+Channel Currents

2001 ◽  
Vol 276 (50) ◽  
pp. 47512-47517 ◽  
Author(s):  
Moritz Bünemann ◽  
Markus M. Bücheler ◽  
Melanie Philipp ◽  
Martin J. Lohse ◽  
Lutz Hein
Keyword(s):  
Action Potential ◽  
G Protein ◽  
Adrenergic Receptor ◽  
Hek293 Cells ◽  
Receptor Subtype ◽  
Receptor Subtypes ◽  
Intact Cells ◽  
Deactivation Kinetics ◽  
Inwardly Rectifying ◽  
Kinetics Of

Although G protein-coupled receptor-mediated signaling is one of the best studied biological events, little is known about the kinetics of these processes in intact cells. Experiments with neurons from α2A-adrenergic receptor knockout mice suggested that the α2A-receptor subtype inhibits neurotransmitter release with higher speed and at higher action potential frequencies than the α2C-adrenergic receptor. Here we investigated whether these functional differences between presynaptic α2-adrenergic receptor subtypes are the result of distinct signal transduction kinetics of these two receptors and their coupling to G proteins. α2A- and α2C-receptors were stably expressed in HEK293 cells at moderate (∼2 pmol/mg) or high (17–24 pmol/mg) levels. Activation of G protein-activated inwardly rectifying K+(GIRK) channels was similar in extent and kinetics for α2A- and α2C-receptors at both expression levels. However, the two receptors differed significantly in their deactivation kinetics after removal of the agonist norepinephrine. α2C-Receptor-activated GIRK currents returned much more slowly to base line than did α2A-stimulated currents. This observation correlated with a higher affinity of norepinephrine at the murine α2C- than at the α2A-receptor subtype and may explain why α2C-adrenergic receptors are especially suited to control sympathetic neurotransmission at low action potential frequencies in contrast to the α2A-receptor subtype.

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