High-Affinity Benzodiazepine Binding Sites on Rat Peritoneal Mast Cells and RBL-1 Cells: Binding Characteristics and Effects on Granule Secretion

Pharmacology ◽  
1988 ◽  
Vol 36 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Lawrence G. Miller ◽  
Aviva Lee-Paritz ◽  
David J. Greenblatt ◽  
Theoharis C. Theoharides
Keyword(s):  
Mast Cells ◽  
Binding Sites ◽  
Binding Characteristics ◽  
High Affinity ◽  
Peritoneal Mast Cells ◽  
Benzodiazepine Binding ◽  
Rat Peritoneal Mast Cells ◽  
Benzodiazepine Binding Sites ◽  
Granule Secretion

Characterization of two classes of benzodiazepine binding sites in Schistosoma mansoni

Parasitology ◽  
2007 ◽  
Vol 134 (7) ◽  
pp. 1003-1012 ◽  
Author(s):  
F. NOËL ◽  
D. L. MENDONÇA-SILVA ◽  
J-P. B. THIBAUT ◽  
D. V. S. LOPES
Keyword(s):  
Schistosoma Mansoni ◽  
Binding Sites ◽  
Benzodiazepine Receptors ◽  
Large Population ◽  
Benzodiazepine Receptor ◽  
Receptor Complexes ◽  
High Affinity ◽  
Selective Ligand ◽  
Benzodiazepine Binding ◽  
Benzodiazepine Binding Sites

SUMMARYAs we have recently shown that GABA should be considered a putative neurotransmitter inSchistosoma mansoni, the present work aimed to search for GABAAreceptors in adult worms using [3H]-flunitrazepam to label the allosteric benzodiazepine binding site which is classically present on GABAAreceptor complexes. We detected a large population (Bmax=8·25±1·1 pmol . mg protein−1) of high affinity (Kd=33·6±1·5 nm) binding sites for flunitrazepam. These sites harboured a singular pharmacological modulation that does not fit well with a mammalian central benzodiazepine receptor, mainly due to a very high affinity for Ro5-4864 and a very low affinity for clonazepam. We also detected a second population of benzodiazepine binding sites labelled with high affinity (IC50=85 nm) by [3H]-PK11195, a selective ligand of the mammalian peripheral benzodiazepine receptor. In conclusion, this work describes the pharmacological properties of a large population of central-like benzodiazepine receptors supporting their study as putative new targets for the development of anti-parasitic agents. We also describe, for the first time, the presence of peripheral benzodiazepine receptors in this parasite.

scholarly journals Effects of aging on the synthesis of antithrombin-binding sites on heparin chains and heparan sulphate chains in the rat

1995 ◽  
Vol 312 (1) ◽  
pp. 245-249
Author(s):  
A A Horner
Keyword(s):  
Mast Cells ◽  
Binding Sites ◽  
Heparan Sulphate ◽  
Significant Decline ◽  
Male Rats ◽  
High Affinity ◽  
Peritoneal Mast Cells ◽  
Effects Of Aging ◽  
Age Range

[35S]Heparin proteoglycans were isolated from the skins and peritoneal mast cells of male rats aged 2 to 22 months. Their [35S]heparin chains were separated on antithrombin-agarose into fractions with high and low affinities for antithrombin. In skin, the proportion of 35S-labelled high-affinity heparin chains declined from 23% at 2 months to 8% at 12 months and did not change significantly between 12 and 22 months. In peritoneal mast cells, the proportion of 35S-labelled high-affinity heparin chains increased from 14% at 2 months to 21% at 4 months and then did not vary significantly until 15 months of age. By 21 months a consistent and significant decline to 8% occurred. The structures of high-affinity heparin proteoglycans did not change with age. Their decreased proportions, without change in their structure, may indicate that they are produced by a unique subset of mast cells, the proportion of which declines with age. [35S]heparan sulphate chains were isolated from skins and brains of rats in the same age range and fractionated on antithrombin-agarose. There were no significant variations in the proportions of 35S-labelled high-affinity heparan sulphate chains in skin (10%) or brain (24%) between 4 and 22 months of age.

scholarly journals Presence of a high-affinity Ca2+-and Mg2+-dependent ATPase in rat peritoneal mast-cell membranes

1985 ◽  
Vol 226 (1) ◽  
pp. 335-338 ◽  
Author(s):  
L M Amende ◽  
M A Donlon
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Atpase Activity ◽  
Cell Membranes ◽  
Plasma Membranes ◽  
Peritoneal Mast Cell ◽  
High Affinity ◽  
Dependent Atpase ◽  
Peritoneal Mast Cells ◽  
Rat Peritoneal Mast Cells

Purified perigranular and plasma membranes isolated from rat peritoneal mast cells were examined for Ca2+- and Mg2+-dependent ATPase activity. Isolated perigranular membranes contained only a low-affinity Ca2+- or Mg2+-dependent ATPase (Km greater than 0.5 mM). The plasma membranes contained both a low-affinity Ca2+- or Mg2+-dependent ATPase (Km = 0.4 mM, Vmax. = 20 nmol of Pi/min per mg), as well as a high-affinity Ca2+- and Mg2+-dependent ATPase (Km = 0.2 microM, Vmax. = 6 nmol of Pi/min per mg).

Increased density of peripheral benzodiazepine-binding sites in ovarian carcinomas as compared with benign ovarian tumours and normal ovaries

1990 ◽  
Vol 78 (2) ◽  
pp. 155-158 ◽  
Author(s):  
Yeshayahu Katz ◽  
Gilad Ben-Baruch ◽  
Yoel Kloog ◽  
Joseph Menczer ◽  
Moshe Gavish
Keyword(s):  
Ovarian Carcinoma ◽  
Binding Sites ◽  
Ovarian Carcinomas ◽  
Binding Characteristics ◽  
Normal Tissues ◽  
Benign Ovarian Tumours ◽  
Benzodiazepine Binding ◽  
Ovarian Tumours ◽  
Benzodiazepine Binding Sites

1. Benzodiazepines are involved in the control of proliferation and differentiation of normal and malignant cells in vitro. This regulatory ability is probably mediated via peripheral benzodiazepine-binding sites. 2. In the present study we compared the binding characteristics of peripheral benzodiazepine-binding sites in human epithelial ovarian carcinoma with those in benign ovarian tumours and normal ovaries. 3. The affinity and density of peripheral benzodiazepine-binding sites in homogenate preparations of ovarian carcinoma as compared with benign ovarian tumours and with normal tissues (used as controls) were determined using a ligand specific for peripheral benzodiazepine-binding sites, [3H]PK 11195, an isoquinoline carboxamide derivative. 4. We observed a robust (three-to five-fold) increase in the neoplasm compared with benign ovarian tumours and normal tissues, without a concomitant change in affinity values. 5. This finding may reflect a change in the metabolic rates of ovarian cancer which is expressed as the alteration in the density of peripheral benzodiazepine-binding sites.

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