Differential distribution of functional alpha(1)-adrenergic receptor subtypes along the rat tail artery

The rat tail artery has been used for the study of vasoconstriction mediated by alpha(1A)-adrenoceptors (ARs). However, rings from proximal segments of the tail artery (within the initial 4 cm, PRTA) were at least 3- fold more sensitive to methoxamine and phenylephrine (n = 6 - 12; p < 0.05) than rings from distal parts (between the sixth and 10th cm, DRTA). Interestingly, the imidazolines N-[ 5-( 4,5- dihydro- 1H- imidazol-2-yl)-2-hydroxy-5,6,7,8- tetrahydronaphthalen- 1- yl] methanesulfonamide hydrobromide (A-61603) and oxymetazoline, which activate selectively alpha(1A)- ARs, were equipotent in PRTA and DRTA (n = 4 - 12), whereas buspirone, which activates selectively alpha(1D)-AR, was approximate to 70-fold more potent in PRTA than in DRTA (n = 8; p < 0.05). The selective alpha(1D)-AR antagonist 8-[2-[4-(methoxyphenyl)-1-piperazinyl] ethyl]-8-azaspiro[4.5] decane-7,9-dione dihydrochloride (BMY- 7378) was approximate to 70- fold more potent against the contractions induced by phenylephrine in PRTA (pK(B) of approximate to 8.45; n = 6) than in DRTA (pK B of approximate to 6.58; n = 6), although the antagonism was complex in PRTA. 5-Methylurapidil, a selective alpha(1A)-antagonist, was equipotent in PRTA and DRTA (pK(B) of approximate to 8.4), but the Schild slope in DRTA was 0.73 +/- 0.05 ( n = 5). The noncompetitive alpha(1B)-antagonist conotoxin rho-TIA reduced the maximal contraction induced by phenylephrine in DRTA, but not in PRTA. These results indicate a predominant role for alpha(1A)-ARs in the contractions of both PRTA and DRTA but with significant coparticipations of alpha(1D)-ARs in PRTA and alpha(1B)-ARs in DRTA. Semiquantitative reverse transcription-polymerase chain reaction revealed that mRNA encoding alpha(1A)- and alpha(1B)-ARs are similarly distributed in PRTA and DRTA, whereas mRNA for alpha(1D)-ARs is twice more abundant in PRTA. Therefore, alpha(1)-ARs subtypes are differentially distributed along the tail artery. It is important to consider the segment from which the tissue preparation is taken to avoid misinterpretations on receptor mechanisms and drug selectivities. antagonism was complex in PRTA. 5- Methylurapidil, a selective alpha(1A)-antagonist, was equipotent in PRTA and DRTA (pK(B) of approximate to 8.4), but the Schild slope in DRTA was 0.73 +/- 0.05 ( n = 5). The noncompetitive alpha(1B)-antagonist conotoxin rho-TIA reduced the maximal contraction induced by phenylephrine in DRTA, but not in PRTA. These results indicate a predominant role for alpha(1A)-ARs in the contractions of both PRTA and DRTA but with significant coparticipations of alpha(1D)-ARs in PRTA and alpha(1B)-ARs in DRTA. Semiquantitative reverse transcription-polymerase chain reaction revealed that mRNA encoding alpha(1A)- and alpha(1B)- ARs are similarly distributed in PRTA and DRTA, whereas mRNA for alpha(1D)-ARs is twice more abundant in PRTA. Therefore, alpha(1)-ARs subtypes are differentially distributed along the tail artery. It is important to consider the segment from which the tissue preparation is taken to avoid misinterpretations on receptor mechanisms and drug selectivities.

Charge distribution and calcium affinity of sulfated alpha-L-galactans from ascidians. Comparison between linear and highly branched polymers

Calcium binding and charge distribution on highly branched and linear sulfated L-galactans from ascidians have been studied using a metallochromic indicator and conductimetric titrations. The distance between charged groups of the linear and highly branched galactans does not vary despite their marked differences in sulfate/total sugar molar ratios. These results indicate that the sulfated L-galactose units are concentrated in the central polysaccharide core and not intercalated among non-sulfated units. This inference is consistent with the chemical studies of these galactans. Surprisingly, calcium affinity increases with increasing amounts of non-sulfated sugar branches in the molecule. Thus, calcium binding in these polymers is not a simple function of availability of anion binding sites but a more complex calcium-polysaccharide interaction. (C) 1998 Elsevier B.V. Ltd. All rights reserved.

Kinetics of interface state-limited hole injection in alpha-naphthylphenylbiphenyl diamine (alpha-NPD) thin layers

Injection-limited operation is identified in thin-film, alpha-NPD-based diodes. A detailed model for the impedance of the injection process is provided which considers the kinetics of filling/releasing of interface states as the key factor behind the injection mechanism. The injection model is able to simultaneously account for the steady-state, current-voltage (J-V) characteristics and impedance response. and is based on the sequential injection of holes mediated by energetically distributed surface states at the metal-organic interface. The model takes into account the vacuum level offset caused by the interface dipole, along with the partial shift of the interface level distribution with bias voltage. This approach connects the low-frequency (similar to 1 Hz) capacitance spectra, which exhibits a transition between positive to negative values, to the change in the occupancy of interface states with voltage. Simulations based on the model allow to derive the density of interface states effectively intervening in the carrier injection (similar to 5 x 10(12) cm(-2)), which exhibit a Gaussian-like distribution. A kinetically determined hole barrier is calculated at levels located similar to 0.4 eV below the contact work function. (C) 2008 Elsevier B.V. All rights reserved.

Activation of alpha(2)-adrenergic receptors into the lateral parabrachial nucleus enhances NaCl intake in rats

Water and NaCl intake is strongly inhibited by the activation of alpha(2)-adrenergic receptors with clonidine or moxonidine (alpha(2)-adrenergic/imidazoline agonists) injected peripherally or into the forebrain and by serotonin and cholecystokinin in the lateral parabrachial nucleus (LPBN). Considering that alpha(2)-adrenergic receptors exist in the LPBN and the similar origin of serotonergic and adrenergic afferent pathways to the LPBN, in this study we investigated the effects of bilateral injections of moxonidine alone or combined with RX 821002 (alpha(2)- adrenergic antagonist) into the LPBN on 1.8% NaCl and water intake induced by the treatment with s.c. furosemide (10 mg/kg)+captopril (5 mg/kg). Additionally, we investigated if moxonidine into the LPBN would modify furosemide+captopril-induced c-fos expression in the forebrain. Male Holtzman rats with cannulas implanted bilaterally in the LPBN were used. Contrary to forebrain injections, bilateral LPBN injections of moxonidine (0.1, 0.5 and 1 nmol/0.2 mul) strongly increased furosemide+captopril-induced 1.8% NaCl intake (16.6 +/- 2.7, 44.5 +/- 3.2 and 44.5 +/- 4.3 ml/2 h, respectively, vs. vehicle: 6.9 +/- 1.5 ml/2 h). Only the high dose of moxonidine increased water intake (23.3 +/- 3.8 ml/2 h, vs. vehicle: 12.1 +/- 2.6 ml/2 h). Prior injections of RX 821002 (10 and 20 nmol/0.2 mu1) abolished the effect of moxonidine (0.5 nmol) on 1.8% NaCl intake. Moxonidine into the LPBN did not modify furosemide+captopril-induced c-fos expression in forebrain areas related to the control of fluid-electrolyte balance. The results show that the activation of LPBN a2-adrenergic receptors enhances furosemide+captopril-induced 1.8% NaCl and water intake. This enhancement was not related to prior alteration in the activity of forebrain areas as suggested by c-fos expression. Previous and present results indicate opposite roles for alpha(2-)adrenergic receptors in the control of sodium and water intake according to their distribution in the rat brain. (C) 2004 IBRO. Published by Elsevier Ltd. All rights reserved.

Oral distribution of Candida species and presence of oral lesions in Brazilian leprosy patients under multidrug therapy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Differential regulation of the release of tumor necrosis factor-alpha and of eicosanoids by mast cells in rat airways after antigen challenge

Background: Rat trachea display a differential topographical distribution of connective tissue mast cells (CTMC) and mucosal mast cells (MMC) that may imply regional differences in the release of allergic mediators such as tumor necrosis factor-alpha (TNF-alpha) and eicosanoids.Aim: To evaluate the role of CTMC and MMC for release of TNF-alpha and eicosanoids after allergenic challenge in distinct segments of rat trachea.Materials and methods: Proximal trachea ( PT) and distal trachea (DT) from ovalbumin (OVA)-sensitized rats, treated or not with compound 48/80 ( 48/80) or dexamethasone, were incubated in culture medium. After OVA challenge, aliquots were collected to study release of TNF-alpha and eicosanoids.Results: Release of TNF-alpha by PT upon OVA challenge peaked at 90 min and decayed at 6 and 24 h. Release from DT peaked at 30-90 min and decayed 6 and 24 h later. When CTMC were depleted with 48/80, OVA challenge exacerbated the TNF-alpha release by PT at all time intervals, while DT exacerbated TNF-alpha levels 6 and 24 h later only. Dexamethasone reduced TNF-alpha production after 90 min of OVA challenge in PT and at 3 and 6h in DT. OVA challenge increased prostaglandin D-2 in DT and leukotriene B-4 in both segments but did not modify prostaglandin E-2 and leukotriene C-4 release.Conclusion: OVA challenge induces TNF-alpha release from MMC, which is negatively regulated by CTMC. The profile of TNF-alpha and eicosanoids depends on the time after OVA challenge and of the tracheal segment considered.

Identification, content, and distribution of type VI collagen in bovine tendons

Tendon composition changes according to differentiation, mechanical load, and aging. In this study, we attempted to identify, localize, and quantify type VI collagen in bovine tendons. Type VI collagen was identified by the electrophoretic behavior of the alpha chains and Western blotting, and by rotary shadowing. Type VI collagen was extracted from powdered tendon with three sequential 24-h extractions with 4 M guanidine-HCl. The amount of type VI collagen was determined by enzyme-linked immunosorbent assay for purely tensional areas and for the compressive fibrocartilage regions of the deep flexor tendon of the digits, for the corresponding fetal and calf tendons, and for the extensor digital tendon. The distal fibrocartilaginous region of the adult tendon was richer in type VI collagen than the tensional area, reaching as much as 3.3 mg/g (0.33%) of the wet weight. Calf tendons showed an accumulation of type VI at the fibrocartilage site. Immunocytochemistry demonstrated that type VI collagen was evenly distributed in the tensional areas of tendons but was highly concentrated around the fibrochondrocytes in the fibrocartilages. The results demonstrate that tendons are variable with regard to the presence and distribution of type VI collagen. The early accumulation of type VI collagen in the region of calf tendon that will become fibrocartilage in the adult suggests that it is a good marker of fibrocartilage differentiation. Furthermore, the distribution of type VI collagen in tendon fibrocartilage indicates that it organizes the pericellular environment and may represent a survival factor for these cells.

Estrogen receptors alpha and beta in male and female gerbil prostates

The Mongolian gerbil (Meriones unguiculatus, Gerbilinae: Muridae) is useful for prostate studies, because both males and females spontaneously develop prostatic disorders with age. Estrogens regulate prostate homeostasis via two estrogen receptors, ER alpha (ESR1) and ER beta (ESR2), but the cellular distribution and regulation of these receptors in the gerbil prostate has not been described. Both receptors were localized by immunohistochemistry in the ventral prostate of intact male and female gerbils, in males 7 and 21 days after castration, and in females treated with testosterone for 7 and 21 days. In male and female adult gerbils, ER alpha was detected mainly in prostatic stromal cells, whereas ER beta was present mostly in secretory and basal cells. More ER alpha-positive stromal cells were found in females than in males, as was a reduction toward the male value in females treated with testosterone. Castration did not alter ER alpha expression. Testosterone was necessary for maintenance of ER beta in the male prostate epithelium: ER beta expression declined markedly in prostates of males older than 1 yr, and castration of 4-mo-old males caused a reduction in ER beta to levels seen in 1-yr-old males. Because ER beta is an antiproliferative receptor, its loss with age may predispose the aging gerbil to proliferative diseases of the prostate. © 2013 by the Society for the Study of Reproduction, Inc.

Alpha and beta diversity of lepidoptera in eucalyptus plantations in the amazonian region of Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Differential expression of aromatase, estrogen receptor alpha and 17 beta-HSD associated with the processes of total testicular regression and recrudescence in the bat Myotis nigricans (Chiroptera: Vespertilionidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural and electronic analysis of the atomic scale nucleation of Ag on alpha-Ag2WO4 induced by electron irradiation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Elucidating the real-time Ag nanoparticle growth on alpha-Ag2WO4 during electron beam irradiation: experimental evidence and theoretical insights

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at root s=7TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)