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1.
BMC Pulm Med ; 23(1): 25, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36653788

RESUMO

BACKGROUND: To compare the severity of pulmonary embolism (PE) and the long-term complications between patients with and without COVID-19, and to investigate whether the tools for risk stratification of death are valid in this population. METHODS: We retrospectively included hospitalized patients with PE from 1 January 2016 to 31 December 2022. Comparisons for acute episode characteristics, risk stratification of the PE, outcomes, and long-term complications were made between COVID and non-COVID patients. RESULTS: We analyzed 116 (27.5%) COVID patients and 305 (72.4%) non-COVID patients. In patients with COVID-19, the traditional risk factors for PE were absent, and the incidence of deep vein thrombosis was lower. COVID patients showed significantly higher lymphocyte count, lactate dehydrogenase, lactic acid, and D-dimer levels. COVID patients had PE of smaller size (12.3% vs. 25.5% main pulmonary artery, 29.8% vs. 37.1% lobar, 44.7% vs. 29.5% segmental and 13.2% vs. 7.9% subsegmental, respectively; p < 0.001), less right ventricular dysfunction (7.7% vs. 17.7%; p = 0.007) and higher sPESI score (1.66 vs. 1.11; p < 0.001). The need for mechanical ventilation was significantly higher in COVID patients (8.6% vs. 1.3%; p < 0.001); However, the in-hospital death was less (5.2% vs. 10.8%; p = 0.074). The incidence of long-term complications was lower in COVID cohort (p < 0.001). PE severity assessed by high sPESI and intermediate and high-risk categories were independently associated with in-hospital mortality in COVID patients. CONCLUSION: The risk of in-hospital mortality and the incidence of long-term complications were lower in COVID-19. The usual tools for risk stratification of PE are valid in COVID patients.


Assuntos
COVID-19 , Embolia Pulmonar , Humanos , Mortalidade Hospitalar , COVID-19/complicações , Estudos Retrospectivos , Embolia Pulmonar/complicações , Artéria Pulmonar , Medição de Risco
2.
Rev. Asoc. Esp. Neuropsiquiatr ; 33(119): 479-495, jul.-sept. 2013.
Artigo em Espanhol | IBECS | ID: ibc-114054

RESUMO

En la población con discapacidad intelectual (DI) hay una elevada morbilidad psiquiátricaconductual. Se estima que por este motivo entre 1/3 y 3/4 de estas personas reciben antipsicóticos. Existe un consenso de expertos para guiar la toma de decisiones farmacoterapéuticas en estos casos. Su aplicación conseguiría una mayor eficacia del tratamiento, reduciendo los problemas conductuales, mejorando las habilidades adaptativas. El “Inventory for client and agency planning” (ICAP) es un instrumento para valoración y evaluación de servicios para personas con DI, que incluye escalas para puntuación de problemas conductuales y de conductas adaptativas. Para determinar la asociación entre el seguimiento de las recomendaciones farmacoterapeuticas de los expertos y las puntuaciones de los problemas conductuales y las habilidades adaptativas en un grupo de sujetos con DI, se realizó un estudio observación transversal. El tratamiento farmacológico recibido por cada sujeto de un colectivo de sujetos diagnosticados de DI (CIE-10) se clasificó como conforme o no con las recomendaciones de la guía en lo referente a los criterios de indicación, dosis, duración y polifarmacia. Se compararon las puntuaciones de conducta adaptativa y de problemas de conducta del ICAP en función de la conformidad del tratamiento con los criterios. El cumplimiento del criterio de dosis se asoció con mejor conducta adaptativa (p<0,05), el cumplimiento de los criterios de duración y polifarmacia se asociahubo asociación entre cumplimiento del criterio de indicación con la puntuación de problemas de conducta, ni de las habilidades adaptativas (AU)


Subjects with Intellectual Disability (ID) are frequently affected by behavioral and psychiatric co-mobility. As a consequence between 1/3 and ¾ are under antipsychotic treatment. It is available an expert consensus guideline with the purpose of guiding pharmacological treatment decisions. The achievement of expert recommendations may optimize drug therapy efficacy and reduce behavioral problems as well as enhance adaptive abilities. The “Inventory for client and agency planning” (ICAP) is a psychometric tool designed to assess health care to ID patients, and includes items that grade behavioral and adaptive problems. We designed a transversal study in order to determine the association between the follow-up of expert recommendations and the scores achieved on behavioral and adaptive problems items. Drug therapy been prescribed to patients diagnosed of ID (CIE-10) was analyzed and classified into a dichotomous “Do” or “Do not” achieve guideline recommendations in regard of several pharmaceutical aspects such as drug therapy indication, dosage, treatment duration and poly-pharmacy. Scores from ICAP tool as compared to guideline compliance. Follow-up of dose criteria was associated to a better adaptive behavior (p<0,05) and follow-up of poly-pharmacy criteria and duration treatment criteria was associated better behavioral outcomes (p<0,05). We found no association between follow-up of indication criteria and behavioral or adaptive problems (AU)


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Psicofarmacologia/instrumentação , Psicofarmacologia/métodos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/tratamento farmacológico , Transtornos Mentais/complicações , Transtornos Mentais/diagnóstico , Transtornos Mentais/tratamento farmacológico , Adaptação Psicológica , Adaptação Psicológica/fisiologia , Psicofarmacologia/organização & administração , Psicofarmacologia/normas , Deficiência Intelectual/psicologia , Medicina do Comportamento/métodos , Pesquisa Comportamental/métodos , Polimedicação , Estudos Transversais/métodos , Estudos Transversais
3.
Immunity ; 5(3): 275-83, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8808682

RESUMO

In the immune system, apoptosis is involved in intrathymic elimination of self-reactive thymocytes and in peripheral T cell tolerance to exogenous antigens. Here, we describe the role in T cell apoptosis of P(2x1), a nonselective cation channel activated by ATP. P(2X1) molecules are up-regulated in thymocytes during dexamethasone-induced apoptosis, and antagonists to these receptors protect thymocytes from cell death. Moreover, P(2X1) mRNA and protein levels increase in thymocytes induced to die in vivo by the superantigen staphylococcal enterotoxin B. In contrast, T cells undergoing apoptosis in the periphery do not express P(2X1). The demonstration that P(2X1) ion channels play a role in the apoptosis of thymocytes but not peripheral T cells illustrates a novel mechanism contributing to thymocyte cell death and opens new possibilities for investigating clonal deletion in the thymus.


Assuntos
Apoptose , Canais Iônicos/fisiologia , Receptores Purinérgicos P2/fisiologia , Linfócitos T/fisiologia , Trifosfato de Adenosina/antagonistas & inibidores , Animais , Dexametasona/farmacologia , Enterotoxinas/farmacologia , Feminino , Ativação do Canal Iônico , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , RNA Mensageiro/análise , Receptores Purinérgicos P2/genética
4.
Br J Pharmacol ; 118(7): 1806-12, 1996 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8842447

RESUMO

1. We have recently provided evidence that [35S]-adenosine 5'-O-[3-thiotriphosphate] ([35S]-ATP gamma S) can label the human bladder recombinant P2X1 purinoceptor (human P2X1 purinoceptor). In this study we have characterized the binding of [35S]-ATP gamma S to a second P2X purinoceptor subtype, the rat PC12 phaeochromocytoma cell recombinant P2X2 purinoceptor (rat P2X2 purinoceptor), and compared its binding properties with those of both endogenous and recombinant P2X1 purinoceptors. 2. Infection of CHO-K1 cells with the rat P2X2 purinoceptor using Semliki forest virus (SFV) resulted in the expression of high affinity (pKd = 9.3; Bmax = 18.1 pmol mg-1 protein) binding sites for [35S]-ATP gamma S but not for [3H]-alpha, beta-methylene ATP ([3H]-alpha beta meATP). Since functional P2X purinoceptors could be detected electrophysiologically in these cells, but not in non-infected or CHO-K1 cells infected with SFV containing the LacZ gene, these results suggest that the rat P2X2 purinoceptor can be labelled using [35S]-ATP gamma S. 3. The binding characteristics of the rat P2X2 purinoceptor were compared with those of the human P2X1 purinoceptor, which was also expressed in the CHO-K1 cells using SFV. A major difference between the two recombinant P2X purinoceptor types was in the binding characteristics of alpha, beta-methylene ATP (alpha beta meATP). Thus, in the absence of divalent cations, alpha beta meATP possessed low affinity for both the human P2X1 purinoceptor (pIC50 = 7.2) and rat P2X2 purinoceptor (pIC50 = 7.1) labelled using [35S]-ATP gamma S. However, when the recombinant P2X purinoceptors were labelled with [3H]-alpha beta meATP in the presence of 4 mM CaCl2, the affinity of alpha beta meATP for the human P2X1 purinoceptor increased (pIC50 for alpha beta meATP = 8.2), while the affinity of the rat P2X2 purinoceptor for alpha beta meATP did not change (pIC50 for alpha beta meATP = 6.8). 4. Affinity estimates of 15 other nucleotide analogues for the [35S]-ATP gamma S binding sites on the two recombinant P2X purinoceptor subtypes were surprisingly similar (less than 5 fold difference), the only exception being 2'-deoxy ATP which possessed 8 fold higher affinity for rat P2X2 than for human P2X1 purinoceptors. In contrast dextran sulphate and the P2 purinoceptor antagonists, pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid and 4,4'-diisothiocyanatostilbene-2,2' disulphonic acid, possessed 7 to 33 fold higher affinity for the human P2X1 than for the rat P2X2 purinoceptor. These data provide a correlation coefficient (r) of 0.894. 5. There was some evidence for species differences in the P2X1 purinoceptor. Thus, most nucleotides possessed slightly greater (up to 9-10 fold), while the P2 purinoceptor antagonists possessed slightly lower (up to 7-16 fold), affinity for the endogenous rat vas deferens and rat bladder P2X1 purinoceptors than for the human recombinant P2X1 purinoceptor. These differences were reflected in a slightly lower correlation coefficient, when comparing across species between the human recombinant P2X1 purinoceptor and the endogenous P2X1 purinoceptors labelled in either the rat deferens (r = 0.915) or the rat bladder (r = 0.932), than when comparing within species between the endogenous rat vas deferens and rat bladder P2X1 purinoceptors (r = 0.995). 6. In summary, [35S]-ATP gamma S can be used to label the recombinant P2X1 and P2X2 purinoceptors. Despite the marked differences reported between these two forms of P2X purinoceptor in functional studies, the differences in binding studies were more limited. However, a number of antagonists could discriminate between the P2X purinoceptor subtypes in the binding studies raising expectations that selective antagonists for these receptors can be developed.


Assuntos
Receptores Purinérgicos P2/metabolismo , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/farmacologia , Marcadores de Afinidade , Animais , Células CHO , Cricetinae , Vetores Genéticos , Humanos , Técnicas In Vitro , Músculo Liso/efeitos dos fármacos , Músculo Liso/metabolismo , Células PC12 , Antagonistas do Receptor Purinérgico P2 , Ratos , Proteínas Recombinantes/metabolismo , Vírus da Floresta de Semliki/genética , Vírus da Floresta de Semliki/metabolismo , Especificidade da Espécie , Transfecção
5.
Br J Pharmacol ; 117(6): 1254-60, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8882623

RESUMO

1. The binding of [3H]-alpha beta meATP, [35s]-ATP gamma S and [alpha 33P]-ATP to a human bladder P2X purinoceptor, transiently expressed in CHO-K1 cells using the Semliki Forest Virus (SFV) expression system, was examined. The characteristics of the binding sites were compared with results obtained in rat vas deferens, a tissue in which the radioligands are thought to label P2X purinoceptors and in which the endogenous P2X purinoceptor displays high homology with the human bladder P2X purinoceptor. 2. In non-infected CHO-K1 cells, 100 microM ATP evoked only small inward currents (40 pA) in approximately 30% of the cells when studied by the whole-cell voltage clamp technique. In membranes prepared from either these non-infected cells or cells infected with SFV containing the LacZ gene (SFV-LacZ), [3H]-alpha beta meATP bound with low affinity (pKd = 7.04; Bmax = 8.88 pmol ml-1 protein) and there was only a low density of [35S]-ATP gamma S binding sites (pKd = 8.74; Bmax = 358 fmol ml-1 protein). These binding sites differed from those present in rat vas deferens. Thus, pIC50 values for alpha beta meATP (6.5) and L-beta gamma meATP (4.0) at the [3H]-alpha beta meATP binding sites in non-infected CHO-K1 cells were much lower than the respective pIC50 values of 8.3 and 7.7, determined in rat vas deferens. Similarly, affinity estimates (pIC50 values) for ATP (6.82), 2-meS-ATP (5.43), ATP gamma S (7.06) and alpha beta meATP (4.84) at the [35S]-ATP gamma S binding sites in non-infected CHO-K1 cells were up to 2291 fold lower than the respective values of 9.01, 8.79, 8.73 and 7.57, determined in rat vas deferens. 3. In CHO-K1 cells infected using SFV containing the cDNA for the human bladder P2X purinoceptor (SFV-h.P2X), ATP, 2-meS-ATP and alpha beta meATP evoked large inward currents (2-7 nA) in whole cell voltage clamp studies. In membranes prepared from these SFV-h.P2X infected cells, [3H]-alpha beta meATP binding was increased, compared to that measured in the non infected or SFV-LacZ infected cells, with only high affinity [3H]-alpha beta meATP binding sites being detected (pKd = 9.21; Bmax = 3.54 pmol mg-1 protein). The pIC50 values for alpha beta meATP (8.2) and L-beta gamma meATP (7.2) in competing for these sites were the same or similar to the values determined in rat vas deferens. 4. A high density of [35H]-ATP gamma S binding sites (pKd = 9.09; Bmax = 6.82 pmol mg-1 protein) was also present in the membranes from CHO-K1 cells infected with SFV-h.P2X and affinity estimates (pIC50 values) for ATP (8.93), 2-meS-ATP (8.23), ATP gamma S (8.08), and alpha beta meATP (7.17) at competing for these sites were as much as 631 fold higher than the respective values determined in non-infected CHO-K1 cells but were close to the values determined in rat vas deferens. Similar data were obtained with [alpha 33P]-ATP as radioligand. 5. These data suggest that [3H]-alpha beta meATP, [35S]-ATP gamma S and [33P]-ATP label the human bladder recombinant P2X purinoceptor expressed in CHO-K1 cells following infection with SFV-h.P2X and provide further corroborative evidence to support the contention that the high affinity binding sites for these radioligands in rat vas deferens are P2X purinoceptors.


Assuntos
Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/metabolismo , Receptores Purinérgicos P2/metabolismo , Bexiga Urinária/metabolismo , Animais , Células CHO , Linhagem Celular , Cricetinae , Humanos , Masculino , Técnicas de Patch-Clamp , Radioisótopos de Fósforo , Reação em Cadeia da Polimerase , Ratos , Ratos Sprague-Dawley , Receptores Purinérgicos P2/efeitos dos fármacos , Proteínas Recombinantes/metabolismo , Radioisótopos de Enxofre , Trítio , Ducto Deferente/metabolismo
6.
Mol Pharmacol ; 48(2): 178-83, 1995 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7544432

RESUMO

cDNAs encoding P2x purinoceptors from human bladder smooth muscle and from rat PC-12 cells were expressed in oocytes and human embryonic kidney 293 cells. Agonist potencies of 2-methylthio-ATP = 2-chloro-ATP = ATP > = 2'- and 3'-O-(4-benzoylbenzoyl)-ATP > or = adenosine-5'-O-(3-thio)-triphosphate > or = P1,P5-di(adenosine-5') pentaphosphate >> ADP prevailed for both P2x purinoceptors. There were two main differences in agonist sensitivity between the two receptors. First, ATP was 10 times more potent at the receptor from bladder (EC50, 0.8 microM) than at the receptor from PC-12 cells (EC50, 8.2 microM). Second, alpha,beta-methylene-ATP and L- and D-beta,gamma-methylene-ATP were agonists in cells expressing the bladder smooth muscle receptor (EC50, 1-3 microM) but were ineffective in cells expressing the PC-12 receptor. The P2 purinoceptor antagonists suramin, pyridoxal phosphate 6-azophenyl-2',4'-disulfonic acid, and pyridoxal-5-phosphate acted similarly at both receptor forms, producing noncompetitive inhibition, with IC50 values of 1-5 microM for suramin and pyridoxal phosphate 6-azophenyl-2',4'-disulfonic acid and 10-20 microM for pyridoxal-5-phosphate. 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic acid distinguished receptor subtypes, producing potent inhibition of the bladder smooth muscle P2x-mediated response, with an IC50 value of 3 microM; it inhibited the PC-12 form by < 40% at 100 or 300 microM. This study thus defines the pharmacological properties of homo-oligomeric forms of these two types of cloned P2x receptor channels.


Assuntos
Trifosfato de Adenosina/fisiologia , Ativação do Canal Iônico , Canais Iônicos/efeitos dos fármacos , Receptores Purinérgicos P2/efeitos dos fármacos , Ácido 4,4'-Di-Isotiocianoestilbeno-2,2'-Dissulfônico/farmacologia , Nucleotídeos de Adenina/química , Nucleotídeos de Adenina/farmacologia , Animais , Linhagem Celular , Clonagem Molecular , DNA Complementar , Humanos , Canais Iônicos/genética , Canais Iônicos/fisiologia , Células PC12 , Fosfato de Piridoxal/análogos & derivados , Fosfato de Piridoxal/farmacologia , Ratos , Receptores Purinérgicos P2/genética , Receptores Purinérgicos P2/fisiologia , Suramina/farmacologia
8.
Recept Channels ; 3(4): 283-9, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8834001

RESUMO

A cDNA encoding an ion channel (hP2X), gated by extracellular ATP, was isolated from the human urinary bladder. It encodes a 399 amino acid protein, composed of a cysteine-rich central domain, flanked by two hydrophobic regions. A comparison of the sequence with those of the corresponding rat and mouse proteins shows predominantly conservative substitutions of hydrophilic residues. Northern blot analysis demonstrated the presence of the mRNA in several human tissues and established that the distal untranslated portion of the mRNA includes an 'expressed sequence tag' for the differentiation of the hemopoetic cell line, HL60. By fluorescent in situ hybridization the hP2X gene was mapped to the short arm of human chromosome 17. Expressed in Xenopus oocytes, the receptor was sensitive to the purinergic agonists ATP and alpha,beta-methylene ATP.


Assuntos
Cromossomos Humanos Par 17 , Receptores Purinérgicos P2/genética , Bexiga Urinária/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Northern Blotting , Mapeamento Cromossômico , DNA Complementar , Células HL-60 , Humanos , Hibridização in Situ Fluorescente , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Homologia de Sequência de Aminoácidos
9.
Nature ; 371(6497): 516-9, 1994 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-7523951

RESUMO

Extracellular ATP exerts its effects through P2 purinoceptors: these are ligand-gated ion channels (P2x) or G-protein-coupled receptors (P2Y, P2U). ATP at P2x receptors mediates synaptic transmission between neurons and from neurons to smooth muscle, being responsible, for example, for sympathetic vasoconstriction in small arteries and arterioles. We have now cloned a complementary DNA encoding the P2x receptor from rat vas deferens and expressed it in Xenopus oocytes and mammalian cells. ATP activates a cation-selective ion channel with relatively high calcium permeability. Structural predictions suggest that the protein (399 amino acids long) is mostly extracellular and contains only two transmembrane domains plus a pore-forming motif which resembles that of potassium channels. The P2x receptor thus defines a new family of ligand-gated ion channels.


Assuntos
Trifosfato de Adenosina/metabolismo , Ativação do Canal Iônico , Receptores Purinérgicos P2/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Clonagem Molecular , DNA Complementar , Humanos , Canais Iônicos/metabolismo , Ligantes , Masculino , Dados de Sequência Molecular , Oócitos , Técnicas de Patch-Clamp , Agonistas do Receptor Purinérgico P2 , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Purinérgicos P2/classificação , Receptores Purinérgicos P2/genética , Distribuição Tecidual , Ducto Deferente/metabolismo , Xenopus
10.
Proc Natl Acad Sci U S A ; 89(20): 9949-53, 1992 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-1409725

RESUMO

The major brain nicotinic acetylcholine receptor is assembled from two subunits termed alpha 4 and n alpha 1. When expressed in Xenopus oocytes, these subunits reconstitute a functional acetylcholine receptor that is inhibited by progesterone levels similar to those found in serum. In this report, we show that the steroid interacts with a site located on the extracellular part of the protein, thus confirming that inhibition by progesterone is not due to a nonspecific perturbation of the membrane bilayer or to the activation of second messengers. Because inhibition by progesterone does not require the presence of agonist, is voltage-independent, and does not alter receptor desensitization, we conclude that the steroid is not an open channel blocker. In addition, we show that progesterone is not a competitive inhibitor but may interact with the acetylcholine binding site and that its effect is independent of the ionic permeability of the receptor.


Assuntos
Encéfalo/fisiologia , Progesterona/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Acetilcolina/farmacologia , Regulação Alostérica , Animais , Sítios de Ligação , Colesterol/farmacologia , Técnicas In Vitro , Ativação do Canal Iônico/efeitos dos fármacos , Potenciais da Membrana , Oócitos , Mutação Puntual , Receptores Nicotínicos/química , Relação Estrutura-Atividade , Testosterona/farmacologia , Xenopus laevis
11.
Neuroreport ; 2(5): 277-80, 1991 May.
Artigo em Inglês | MEDLINE | ID: mdl-1717043

RESUMO

Application of progesterone to Xenopus oocytes expressing a cloned neuronal nicotinic acetylcholine (nAChR) revealed two effects. The first effect was a fully reversible reduction of the current induced by acetylcholine (ACh), its onset being nearly instantaneous. The second effect, which developed in a few hours, was an irreversible suppression of ACh-evoked currents. The transient inhibition had an apparent Ki of 7 microM when tested with 50 nM ACh, but the percentage of inhibition was positively correlated to the ACh concentration. A reduction of ACh-induced currents which appeared immediately upon progesterone application was also observed with muscle nAChR expressed in oocytes and with nAChR on membrane patches isolated from ciliary ganglion neurons. Thus nAChRs are modulated by progesterone and steroids may play an important role in nicotinic cholinoception.


Assuntos
Antagonistas Nicotínicos , Esteroides/farmacologia , Xenopus/fisiologia , Animais , Eletrofisiologia , Feminino , Técnicas In Vitro , Canais Iônicos/efeitos dos fármacos , Cinética , Neurônios/fisiologia , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Progesterona/farmacologia
12.
Neuron ; 5(6): 847-56, 1990 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1702646

RESUMO

cDNA and genomic clones encoding alpha 7, a novel neuronal nicotinic acetylcholine receptor (nAChR) alpha subunit, were isolated and sequenced. The mature alpha 7 protein (479 residues) has moderate homology with all other alpha and non-alpha nAChR subunits and probably assumes the same transmembrane topology. alpha 7 transcripts transiently accumulate in the developing optic tectum between E5 and E16. They are present in both the deep and the superficial layers of E12 tectum. In Xenopus oocytes, the alpha 7 protein assembles into a homo-oligomeric channel responding to acetylcholine and nicotine. The alpha 7 channel desensitizes very rapidly, rectifies strongly above -20 mV, and is blocked by alpha-bungarotoxin. A bacterial fusion protein encompassing residues 124-239 of alpha 7 binds labeled alpha-bungarotoxin. We conclude that alpha-bungarotoxin binding proteins in the vertebrate nervous system can function as nAChRs.


Assuntos
Bungarotoxinas/farmacologia , Receptores Nicotínicos/fisiologia , Acetilcolina/farmacologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Bungarotoxinas/metabolismo , Embrião de Galinha , Galinhas , Clonagem Molecular , DNA/genética , Eletrofisiologia , Canais Iônicos/efeitos dos fármacos , Canais Iônicos/fisiologia , Substâncias Macromoleculares , Dados de Sequência Molecular , Nicotina/farmacologia , Oócitos/metabolismo , RNA Mensageiro/metabolismo , Receptores Nicotínicos/química , Receptores Nicotínicos/genética , Proteínas Recombinantes de Fusão/metabolismo , Homologia de Sequência do Ácido Nucleico , Colículos Superiores/embriologia , Colículos Superiores/metabolismo , Xenopus
13.
J Biol Chem ; 265(29): 17560-7, 1990 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-1698777

RESUMO

In vertebrates, neuronal nicotinic acetylcholine receptors (nAChRs) assemble in an unknown stoichiometry from two homologous subunits, an alpha and a non-alpha. How large is the repertoire of these subunits and how many subtypes of functionally different nAChRs can they constitute? We found in the avian genome a cluster of three closely linked genes spanning 28 kilobase pairs and encoding three proteins, n alpha 3, alpha 3, and alpha 5, that have the features expected of neuronal nAChR subunits. Gene n alpha 3 lies 5' of alpha 3 (whose role in cholinoception has already been established) and is transcribed from the same DNA strand, whereas alpha 5 lies 3' of alpha 3 and is transcribed from the opposite DNA strand. The structure of the n alpha 3 and alpha 5 genes consists of six exons with precisely conserved splice sites and is identical to the structure of the previously characterized avian neuronal receptor subunit genes alpha 2, alpha 3, alpha 4, and n alpha 1. alpha 3, n alpha 3, and alpha 5 transcripts are rare in the central nervous system, but alpha 3 and n alpha 3 are readily detectable in embryonic superior cervical and ciliary ganglia. In order to assay function, the gene encoding n alpha 3 and the cDNAs encoding alpha 3, alpha 4, alpha 5, and n alpha 1 were subcloned into an expression vector, and the constructs were injected into Xenopus oocyte nuclei, either singly or in pairwise combinations of one alpha and one non-alpha. One to five days later, ACh sensitivity of the injected oocytes was examined in voltage clamp. The n alpha 3 gene and n alpha 1 cDNA elicited assembly of nAChRs when coinjected with alpha 3 or alpha 4 cDNA and the electrophysiological properties of the four pairwise combinations were significantly different. alpha 5, however, did not direct the assembly of functional nAChRs when injected alone or in combination with n alpha 1 or n alpha 3.


Assuntos
Família Multigênica , Receptores Nicotínicos/genética , Acetilcolina/farmacologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Galinhas , DNA/sangue , DNA/genética , DNA/isolamento & purificação , Eritrócitos/metabolismo , Gânglios Simpáticos/metabolismo , Biblioteca Gênica , Íntrons , Substâncias Macromoleculares , Dados de Sequência Molecular , RNA/genética , RNA/isolamento & purificação , Receptores Nicotínicos/efeitos dos fármacos , Receptores Nicotínicos/fisiologia , Mapeamento por Restrição , Homologia de Sequência do Ácido Nucleico , Transcrição Gênica
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