Several B2 bradykinin (BK) receptor-specific antagonists including HOE140, NPC17731, and NPC567 exhibited negative intrinsic activity, which was observed as a decrease in basal phosphoinositide hydrolysis in primary cultures of rat myometrial cells, and this response was opposite to that elicited by the agonist BK. The order of potency of the antagonists in attenuating basal activity was essential

In this study we examined the involvement of the focal adhesion-associated proteins p125FAK and paxillin as substrates for bradykinin (BK)-stimulated tyrosine phosphorylation in Swiss 3T3 cells and the potential role of protein kinase C and Ca2+ in these events. BK (1 UM) stimulated tyrosine phosphorylation of p125FAK and paxillin. In addition, BK also increased the phosphotyrosine content of the

In this study we investigated receptor-specific cellular signals elicited by kinin agonists in cultured rabbit superior mesenteric artery smooth muscle cells. Kinins promoted an increase in inositol phosphate formation and arachidonic acid release in these cells. The responses elicited by des- Arg9-bradykinin (des-Arg9-BK), a B1 kinin agonist, were antagonized by des- Arg9[Leu8]-BK, a B1 kinin ant

Bradykinin (BK) and bombesin (BN) stimulate an increase in the tyrosine phosphorylation of a 120-kDa group of proteins (pps120) in Swiss 3T3 cells (Leeb-Lundberg, L. M. F., and Song X.-H. (1991) J. Biol. Chem. 266, 7746-7749). Here, we show that a component of pps120, p125, was specifically immunoprecipitated with antibodies against the p21ras GTPase-activating protein (GAP). The major portion of

Bradykinin receptors have been identified in human gingival fibroblasts; the primary signal transduction pathways and their dependence on calcium have been characterized. Binding data revealed a calcium-independent binding of bradykinin to the cell membrane with a receptor density of 25,000 receptors per cell and a K d of 1.6 nM. The bradykinin receptor-mediated activation of phospholipase C (PLC

We have previously shown that exposure of DDT1 MF-2 smooth muscle cells to the agonist bradykinin (BK) resuits in a rapid B2 kinin receptor-mediated internalization of BK followed by degradation of the intracellular BK [Munoz, C. M., and Leeb-Lundberg, L. M. F. (1992) J. Biol. Chem. 267, 303-309]. Here, we show that BK internalization is paralleled by sequestration of the occupied B2 receptors. Se

Bradykinin exhibits proliferative influences in several types of cells; however, in the present study, bradykinin did not promote DNA synthesis but actually inhibited the DNA synthesis induced by epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) in human gingival fibroblasts (HGF). This dose-dependent inhibitory effect was a specific intracellular interaction in that increas

Primary cultures of cells from late pregnant rat myometrium contain B2 kinin receptors through which bradykinin (BK) stimulates inositol phosphate (InsP) formation and arachidonic acid (20:4) release. Equilibrium binding at 4°C revealed that [34H]BK identified a maximal number of cell surface B2 kinin receptor binding sites on rat myometrial cells of 308 ± 78 fmol/106 cells with apparently a singl

This study was undertaken to evaluate the role of internalization in the action of the peptide autacoid bradykinin (BK). At 4°C [3H]BK binds to an apparently single class of B2 kinin receptors on DDT1 MF-2 smooth muscle cells (C. M. Munoz, S. Cotecchia, and L. M. F. Leeb-Lundberg, manuscript submitted). At this temperature the [3H]BK binding was confined exclusively to the cell surface. On the oth

We have previously reported that [3H]bradykinin ([3H]BK) identifies high- and low-affinity B2 kinin receptor sites in bovine myometrial membranes which are sensitive and insensitive respectively to guanine nucleotides. Here we show that these receptor-binding sites are solubilized by the detergent CHAPS. Equilibrium binding in soluble preparations revealed that [3H]BK identified a maximal number o

We have examined the effect of bradykinin (BK) and other peptide mediators with related cellular actions on tyrosine phosphorylation in confluent Swiss 3T3 fibroblast cells using an anti-phosphotyrosine antibody. Immunoblots of extracts from cells stimulated with BK showed a major heterogeneous band centered at Mr 120,000. Three phosphorylated protein species were present within this band. The low

Barbiturates and the related depressant drugs, etazolate and etomidate, inhibited both the binding of [3H]bicuculline methochloride (BMC) to γ-aminobutyric acid (GABA) receptor sites and the binding of [3H]β-carboline-3-carboxylic acid methyl ester (βCCM) to benzodiazepine receptor sites in mammalian brain. These concentration-dependent effects were chemically specific and stereospecific in a mann

γ-Aminobutyric acid (GABA) increases the rate of 36Cl- efflux from preloaded rat hippocampal slices in a dose-dependent manner (EC50: 400 μM). This action has the pharmacological specificity expected of activation of GABA receptor in that it is mimicked by the agonists muscimol and 3-aminopropanesulfonic acid, and blocked by the antagonists bicuculline and picrotoxinin. GABA uptake inhibitors, nip

A novel high affinity radioiodinated photoaffinity probe, 4-amino-6,7-dimethoxy-2[4-[5(3-[125I]iodo-4-azidophenyl)pentanoyl]-1-piperazinyl]- quinazoline, structurally related to the potent α1-adrenergic antagonist prazosin, was developed and used to covalently label the rat cerebral cortex α1-adrenergic receptor. In the absence of light, this ligand binds to cortex plasma membranes with a dissocia

Benzodiazepine receptor binding heterogeneity evident from differential affinities of some ligands was compared with that suggested by differential interactions with γ-aminobutyric acid (GABA)/bicuculline and pyrazolopyridine/barbiturate receptor sites. The GABA receptor antagonist bicuculline only partially reverses pentobarbital enhancement of [3H] diazepam binding in rat brain membranes, while

Numerous barbiturates, such as (±)-pentobarbital, reversibly enhance the affinity for equilibrium binding of [3H]diazepam to well-washed rat cortical membranes in a chloride-dependent and picrotoxinin-sensitive manner [Leeb-Lundberg et al., Proc. Natl. Acad. Sci. U.S.A. 77:7468-7472 (1980)]. The chemical specificity and stereospecificity of this barbiturate effect in vitro has been examined in det

The two pyrazolopyridines, etazolate (SQ20009) and cartazolate (SQ65396), enhance the binding of [3H]diazepam to benzodiazepine receptor sites in rat brain. This enhancement is due to a change in affinity without a change in maximal binding. Pentobarbital also enhances [3H]diazepam binding by lowering the K(D). Pentobarbital gives a maximal enhancement of benzodiazepine binding slightly greater th