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A Jazayeri

Publications and source records attributed to A Jazayeri.

24 records · Page 2Linked to original sources
PubMed1989

Mineralocorticoid-induced increase in beta-adrenergic receptors of cultured rat arterial smooth muscle cells.

We have investigated the effect of mineralocorticoids on beta-adrenergic receptors in cultured arterial smooth muscle cells. Mineralocorticoid (aldosterone) treatment resulted in a significant increase in beta-adrenergic receptors measured by [3H]dihydroalprenolol (DHA) binding. This effect required at least 20 hours of incubation with aldosterone and was completely blocked by cycloheximide (10 micrograms/ml), indicating protein synthesis was required for this response. Aldosterone at the concentration range of 10(-8)-10(-6) M increased [3H]DHA binding, but was ineffective at 10(-9) M. Scatchard analysis of [3H]DHA binding revealed that the observed significant increase in binding was due to an increased number of binding sites (P less than 0.05), and that the affinity was unchanged. The aldosterone (1 x 10(-8) M) effect was completely blocked by the combination of RU 38486 (10(-6) M) and spironolactone (10(-7) M), but not by the glucocorticoid antagonist RU 38486 alone. While basal c-AMP levels were not changed by aldosterone (10(-6) M) treatment, the isoproterenol (10(-6) M) stimulated level of c-AMP was significantly higher in cells treated with aldosterone (P less than 0.05). We conclude that aldosterone, acting through the mineralocorticoid receptor, has a direct effect on arterial smooth muscle cells mediated through modulation of beta-adrenergic receptors of these cells.

Aldosterone↗
PubMed1989

Beta-adrenergic receptor differences in cultured arterial smooth muscle cells between spontaneously hypertensive and Wistar-Kyoto rats.

In this study, beta-adrenergic receptors of cultured arterial smooth muscle cells (ASMC) from normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were compared. Scatchard analysis of [3H]-dihydroalprenolol hydrochloride (DHA) binding revealed that the maximum binding capacity (Bmax) for [3H]-DHA binding was significantly higher in WKY than in SHR, by twofold (n = 6, P less than 0.0001). Analysis of isoproterenol competition for [3H]-DHA binding by computerized non-linear regression indicated that the two strains have an equal number of high-affinity-state receptors, but that WKY rats have about three times more low-affinity-state receptors than SHR. Isoproterenol stimulated cyclic adenosine monophosphate (cAMP) production in a dose-dependent manner, and dose-response experiments revealed an effective concentration of ligand at which 50% of the maximum effect is observed (EC50) of 5-10 x 10(-8) mol/l isoproterenol for both WKY and SHR. Also, isoproterenol-stimulated cAMP production was inhibited by propranolol in a dose-dependent manner. This study demonstrates that the previously described difference observed for in vivo binding of beta-adrenergic receptors of vessels from SHR is retained in tissue culture of vascular smooth muscle and is, therefore, independent of the elevated plasma catecholamine and blood pressure levels found in SHR. The finding that there is equal cAMP stimulation in WKY and SHR is consistent with the discovery of an equal number of high-affinity-state receptors in the two strains. The difference in total beta-adrenergic receptor number is secondary to the greater number of low-affinity-state receptors found in WKY.

Animals↗
PubMed1988

Beta-adrenergic receptor binding characteristics and responsiveness in cultured Wistar-Kyoto rat arterial smooth muscle cells.

The tone of arterial blood vessels is regulated by the catecholamines through their receptors on arterial smooth muscle cells (ASMC). beta 2-adrenergic receptors of ASMC mediate vasodilation through agonist mediated c-AMP production. Previous reports have described these receptors on freshly isolated blood vessels. This study demonstrates the presence of beta 2-adrenergic receptors on cultured rat ASMC and that these receptors are functional. beta-adrenergic receptor binding was measured using [3H]-dihydroalprenolol (DHA) binding to the membrane of cultured ASMC from normotensive Wistar-Kyoto rats. The ASMC beta-adrenergic receptors have a Kd of 0.56 +/- 0.16 nM and a Bmax of 57.2 +/- 21.7 fmol/mg protein. Competition binding studies revealed a much greater affinity of these receptors for epinephrine than norepinephrine, indicating the preponderance of a beta 2-adrenergic receptor subtype. Isoproterenol stimulation of cultured ASMC resulted in a 14 +/- 7 fold increase in intracellular c-AMP content of these cells indicating these receptors are functional. beta-adrenergic receptors of cultured ASMC provide an excellent system in which the association between hypertension and observed beta-adrenergic receptor differences can be further explored.

Animals↗
PubMed1988

Glucocorticoid modulation of beta-adrenergic receptors of cultured rat arterial smooth muscle cells.

Since both glucocorticoids and catecholamines are involved in the regulation of normal blood pressure, we investigated the modulation of beta-adrenergic receptors of cultured rat arterial smooth muscle cells by glucocorticoids. The synthetic glucocorticoids dexamethasone and RU 28362, at 10(-8) M concentration, increased maximum beta-adrenergic binding but had no effect on the dissociation constant (Kd). Each steroid caused an increase in maximum [3H]dihydroalprenolol binding over the concentration range of 10(-8) to 10(-6) M, but not at 10(-9) M. The glucocorticoid effect on beta-adrenergic receptors of arterial smooth muscle cells required a minimum of 20 hours of incubation in the presence of the steroid and was significantly inhibited by cycloheximide (10 micrograms/ml), indicating that the glucocorticoid effect required protein synthesis. The effect of dexamethasone on [3H]dihydroalprenolol binding was significantly inhibited by the glucocorticoid antagonist RU 38486. Basal and agonist-stimulated cyclic adenosine 3',5'-monophosphate (cAMP) levels in arterial smooth muscle cells, before and after glucocorticoid treatment, were measured as an indicator of the physiological significance of the observed glucocorticoid-induced increase in beta-adrenergic receptor binding. While causing no change in the basal cAMP level, treatment of arterial smooth muscle cells with 10(-6) M dexamethasone for 24 hours increased the 10(-6) M isoproterenol-stimulated cAMP levels.

Animals↗
PubMed1987

Galactoside-binding lectin in human tissues.

Lactose-inhibitable lectin activity has been analyzed by hemagglutination assay in a variety of human tissues and cells obtained at surgery and autopsy. The lectin activity was detected in surgically removed melanoma, sarcoma, colon carcinoma, breast carcinoma, adjacent non-malignant tissues, non-malignant tissues obtained at autopsy and in cells isolated from malignant effusions. Although, on average, malignant tissue had a higher hemagglutinating titer than non-malignant tissue, similar tissues from different individuals varied widely in their apparent lectin content. The lectin was isolated from lung by affinity chromatography and was found to have a native molecular mass of 31,000 daltons and a subunit molecular mass of 14,000 daltons. Utilizing rabbit anti-lung lectin serum in an immunohistochemical assay, the lectin was found to be distributed throughout the cytoplasm of lung epithelial cells. Ouchterlony immunodiffusion analysis confirmed the presence of this lectin in a variety of tissues and in some body fluids. In vitro metabolic radiolabelling experiments showed that the presence of lectin in tissues was most likely due to endogenous synthesis rather than absorption from body fluids. Lectin isolated from several tissues was found to bind to human buffy coat cell receptors.

Electrophoresis, Polyacrylamide Gel↗