scholarly journals Characterization of specific binding sites of 3H-labelled platelet-activating factor ([3H]PAF) and a new antagonist, [3H]SR 27417, on guinea-pig tracheal epithelial cells

1992 ◽  
Vol 284 (1) ◽  
pp. 201-206 ◽  
Author(s):  
J M Herbert
Keyword(s):  
Epithelial Cells ◽  
Guinea Pig ◽  
Binding Sites ◽  
Specific Binding ◽  
Platelet Activating Factor ◽  
Tracheal Epithelial Cells ◽  
Specific Binding Sites ◽  
Paf Receptor ◽  
Tracheal Epithelial ◽  
Paf Receptor Antagonist

Binding of 3H-labelled platelet-activating factor ([3H]PAF) to guinea-pig tracheal epithelial cells was time-dependent, reversible and saturable. Scatchard analysis of the saturation-binding data indicated that [3H]PAF bound to one class of specific binding sites with high affinity (KD = 4.3 +/- 0.03 nM; Bmax. = 0.172 +/- 0.02 fmol/10(5) cells; n = 3). Unlabelled PAF competitively and selectively inhibited the specific binding of [3H]PAF with 50% inhibition at 4.8 +/- 0.07 nM (n = 3). SR 27417, the first member of a newly developed PAF antagonist series, competitively displaced [3H]PAF from its binding sites on guinea-pig tracheal epithelial cells with a Ki of 100 +/- 3 pM (n = 3). Studies carried out in parallel demonstrated that SR 27417 was 40 times more potent than C16-PAF itself and more than 100-fold as active as the best synthetic PAF-receptor antagonist yet described. [3H]SR 27417 displayed high-affinity, specific, reversible as well as saturable binding to a single class of binding sites on tracheal epithelial cells (KD = 94 +/- 7 pM; Bmax. = 0.181 +/- 0.04 fmol/10(5) cells; n = 3). C16-PAF, lyso-PAF, enantio-PAF, SR 27417 and other PAF-receptor antagonists had Ki values which were nearly identical for both [3H]PAF and [3H]SR 27417, demonstrating that in guinea-pig tracheal epithelial cells they have the same binding sites. In conclusion, these data suggest that tracheal epithelial cells contain PAF-specific receptors and indicate that SR 27417 is an extremely potent PAF-receptor antagonist, as well as being a suitable radioligand for labelling PAF receptors on intact cells.

Specific binding of endothelin-1 to canine tracheal epithelial cells in culture

1995 ◽  
Vol 268 (3) ◽  
pp. L424-L431 ◽  
Author(s):  
H. Ninomiya ◽  
X. Y. Yu ◽  
Y. Uchida ◽  
S. Hasegawa ◽  
E. W. Spannhake
Keyword(s):  
Epithelial Cells ◽  
Binding Site ◽  
Binding Sites ◽  
Specific Binding ◽  
Receptor Subtype ◽  
Control Mechanisms ◽  
Endothelin 1 ◽  
Tracheal Epithelial Cells ◽  
Eta Receptor ◽  
Tracheal Epithelial

We have studied the binding of endothelin-1 (ET-1) to cultured canine tracheal epithelial cells. A single specific binding site for 125I-labeled ET-1 was identified with an apparent dissociation constant (Kd) of 0.2 nM, maximal binding sites (Bmax) of 6.7 x 10(3) sites/cell, and half-maximal inhibition (IC50) of 0.3 nM during a 2-h incubation period. The binding of 125I-ET-1 to these cells was inhibited by the presence of unlabeled ET-1, ET-2, or BQ-123, whereas ET-3 and sarafotoxin S6c did not compete for this binding site. These binding characteristics are consistent with those of the ETA receptor. At 37 degrees C, specific binding continuously increased over 18 h, while at 4 degrees C, it reached a plateau by 2 h. The increase in binding at 37 degrees C was not associated with DNA synthesis but was dependent upon protein synthesis, suggesting that epithelial binding sites were produced continuously under these incubation conditions. Our results indicate that canine tracheal epithelial cells possess specific binding sites for ET-1 with characteristics similar to those of the ETA receptor subtype. Because these cells are demonstrated to both release and bind ET-1, the results further suggest that ET-1 is involved in paracrine and/or autocrine control mechanisms in the airway epithelium.

scholarly journals Interaction of platelet-activating factor with cultured guinea pig tracheal epithelial cells

1991 ◽  
Vol 276 (3) ◽  
pp. 593-598 ◽  
Author(s):  
L Churchill ◽  
F H Chilton ◽  
D Proud
Keyword(s):  
Epithelial Cells ◽  
Guinea Pig ◽  
Platelet Activating Factor ◽  
Inflammatory Reactions ◽  
Tracheal Epithelial Cells ◽  
Enhanced Production ◽  
Chain Acyl ◽  
Lipid Product ◽  
Major Route ◽  
Tracheal Epithelial

The present study has examined the interaction of platelet-activating factor (PAF) with cultured guinea pig tracheal epithelial cells (GTE). PAF stimulated GTE to release endogenous arachidonic acid and metabolize it to prostaglandins E2 and F2 alpha (PGE2 and PGF2 alpha). Prostanoid production by GTE in response to PAF was dose-dependent (0.1-100 nM) and was maximal within 5 min. PGE2 and PGF2 alpha levels increased by 3.3 +/- 0.8 and 3.2 +/- 0.6 ng/10(6) cells respectively over basal levels in response to 100 nM-PAF. The ability of GTE to synthesize and/or catabolize PAF was also examined. GTE readily incorporated [3H]acetate into a product which migrated on t.l.c. with PAF. However, further characterization of this product suggested that label had not been incorporated into PAF, but rather that it was incorporated into another lipid product with chromatographic characteristics similar to those of PAF. In contrast, GTE readily metabolized PAF to inactive products. When [3H]PAF was incubated with GTE, 50% of the total [3H]PAF added was catabolized in approx. 15 min. The major route of catabolism of PAF by GTE was the deacetylation-reacylation pathway, which yielded 1-O-[3H]alkyl-2-acyl-sn-glycerophosphocholine. Determination of the nature of the long-chain acyl group incorporated into the sn-2 position of the newly synthesized products revealed that oleic and linoleic acids were the major fatty acids present. Taken together, these results suggest that respiratory epithelial cells respond to stimulation by PAF with enhanced production of PGE2 and PGF2 alpha, and also have the capacity to modulate inflammatory reactions in the airways by their ability to degrade this potent inflammatory mediator.

Specific binding sites for growth hormone in cultured mouse thymic epithelial cells

Life Sciences ◽  
1991 ◽  
Vol 48 (22) ◽  
pp. 2141-2148 ◽  
Author(s):  
Elisabeth Ban ◽  
Marie-Claude Gagnerault ◽  
Hélène Jammes ◽  
Marie-Catherine Postel-Vinay ◽  
France Haour ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Epithelial Cells ◽  
Binding Sites ◽  
Specific Binding ◽  
Thymic Epithelial Cells ◽  
Specific Binding Sites

scholarly journals Prostaglandin E2 increases cyclic AMP and inhibits endothelin-1 production/secretion by guinea-pig tracheal epithelial cells through EP4 receptors

2001 ◽  
Vol 132 (5) ◽  
pp. 999-1008 ◽  
Author(s):  
Stéphane Pelletier ◽  
Jean Dubé ◽  
Annie Villeneuve ◽  
Fernand Gobeil ◽  
Quan Yang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cyclic Amp ◽  
Guinea Pig ◽  
Prostaglandin E2 ◽  
Endothelin 1 ◽  
Tracheal Epithelial Cells ◽  
Tracheal Epithelial

Effect of heavy metals and lanthanum on sugar transport in isolated guinea pig left atria

1980 ◽  
Vol 58 (10) ◽  
pp. 1184-1188 ◽  
Author(s):  
I. Bihler ◽  
L. E. Hoeschen ◽  
P. C. Sawh
Keyword(s):  
Heavy Metals ◽  
Guinea Pig ◽  
Binding Sites ◽  
Specific Binding ◽  
Sugar Transport ◽  
Free Medium ◽  
Specific Binding Sites ◽  
Stimulation Of

The effect of heavy metals on sugar transport in fully resting guinea pig left atria was studied by measuring the tissue–medium distribution of 3-methylglucose. Basal sugar transport was increased significantly by all heavy metals tested (Co2+, Ni2+, Zn2+, Mn2+ (2 mM)) and by La3+ (0.05 mM) but 1 mM La3+ had no effect. The stimulation of sugar transport by insulin, hyperosmolarity, K+-free medium, or 10−5 M ouabain was strongly antagonized by Ni2+, Zn2+, and La3+ but was unaffected by Co2+ and Mn2+. The heavy metals did not affect intracellular Na2+ and K+, whether in the basal state or when the Na+ pump was depressed by ouabain or K+-free medium. The data suggest that Ca2+ antagonistic ions may affect sugar transport both by inhibiting Ca2+ influx and by competing with Ca2+ for specific binding sites presumably involved in the regulation of sugar transport.

Sign in / Sign up

Export Citation Format

Share Document