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PURPOSE OF REVIEW: Exposure to bioaerosols at dairies has long been associated with allergy, respiratory disease, and decreases in lung function. Recent advancements in exposure assessments have aided our understanding on the size distribution and composition of these bioaerosols, but investigations focusing solely on exposures may overlook important intrinsic factors impacting worker's susceptibility to disease. RECENT FINDINGS: In our review, we discuss the most recent studies examining the exposures and genetic factors that contribute to occupational disease in dairy work. We also review more recent concerns in livestock work associated with zoonotic pathogens, antimicrobial resistant genes, and the role of the human microbiome. The studies highlighted in this review demonstrate the need for further research to better understand bioaerosol exposure-response relationships in the context of extrinsic and intrinsic factors, antibiotic-resistant genes, viral pathogens, and the human microbiome to help inform effective interventions that improve respiratory health among dairy farmers.
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Hipersensibilidade , Exposição Ocupacional , Transtornos Respiratórios , Doenças Respiratórias , Humanos , Exposição Ocupacional/efeitos adversos , Fazendeiros , Doenças Respiratórias/epidemiologia , Doenças Respiratórias/etiologiaRESUMO
INTRODUCTION: We aimed to describe the epidemiological situation during the Omicron variant circulation in light of genomic surveillance data in Martinique, a territory with low vaccination rates. PATIENTS AND METHODS: We exploited COVID-19 national databases of virological tests, for the collection of hospital data and for the sequencing data from December 13, 2021 to July 11, 2022. RESULTS: Three prevailing sub-lineages of Omicron have been identified in Martinique (BA.1, BA.2, BA.5) during this period causing three distinct waves characterized by an increase in virological indicators compared to previous waves, with moderate severity in the first and last waves, caused by BA.1 and BA.5, respectively. CONCLUSION: The SARS-CoV-2 outbreak is still progressing in Martinique. Genomic surveillance system in this overseas territory must be continued for rapid detection of emerging variants/sub-lineages.
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COVID-19 , Humanos , Martinica/epidemiologia , COVID-19/epidemiologia , SARS-CoV-2/genética , Surtos de DoençasRESUMO
OBJECTIVES: We aimed to investigate the first Omicron cases detected in France in order to assess case characteristics and provide supporting information on the possible impact of this variant on the healthcare system. METHODS: A standardized questionnaire was used to collect information from confirmed and probable Omicron cases. RESULTS: Median age of 468 investigated cases was 35 years, 376 were symptomatic (89%); 64% were vaccinated with two doses and 7% had received three doses. Loss of smell and taste were reported by 8.3% and 9% of cases, respectively. Seven cases were hospitalized, three of those were unvaccinated (including two with reported precondition). No admissions to intensive care and no deaths were reported. CONCLUSIONS: Our results confirm a mild clinical presentation among the first Omicron cases detected in France and highlight the importance for the national COVID-19 surveillance system to quickly detect and adapt to the emergence of a new variant.
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COVID-19 , SARS-CoV-2 , Adulto , COVID-19/epidemiologia , França/epidemiologia , Hospitalização , Humanos , VacinaçãoRESUMO
The detection of aerosolized viruses can serve as an important surveillance and control tool in agriculture, human health, and environmental settings. Here, we adapted an anion exchange resin-based method, initially developed to concentrate negatively charged viruses from water, to liquid impingement-based bioaerosol sampling. In this method, aerosolized viruses are collected in a 20ml liquid sample contained within widely used impingers, BioSamplers (SKC Inc., Eighty Four, PA), and further concentrated via adsorption to an anion exchange resin that is suspended within this liquid. Viral nucleic acids are then extracted from the resin to facilitate molecular analyses through a reduction in the effective sample volume. For this study, various quantities of two negatively charged viruses, type A and type B influenza viruses (FluMist Quadrivalent vaccine) and the male-specific (F+) RNA coliphage MS2 (MS2), were nebulized into a custom-built bioaerosolization chamber, and sampled using BioSamplers with and without anion exchange resin. Compared to direct testing of the BioSampler liquid, detection was improved by 6.77× and 3.33× for type A and type B influenza viruses, respectively, by using the anion exchange resin. For MS2, the anion exchange resin method allowed for an average improvement in detection of 8.26×.
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Microbiologia do Ar , Levivirus/isolamento & purificação , Orthomyxoviridae/isolamento & purificação , Virologia/métodos , Aerossóis , Resinas de Troca Aniônica , Humanos , Levivirus/genética , Masculino , RNA Viral , Manejo de Espécimes/métodos , Virologia/instrumentaçãoRESUMO
Estrogen acts through two molecularly distinct receptors termed estrogen receptor alpha (ERα) and estrogen receptor beta (ERß) which bind estradiol with similar affinities and mediate the effects of estrogen throughout the body. ERα plays a major role in reproductive physiology and behavior, and mediates classic estrogen signaling in such tissues as the uterus, mammary gland, and skeleton. ERß, however, modulates estrogen signaling in the ovary, the immune system, prostate, gastrointestinal tract, and hypothalamus, and there is some evidence that ERß can regulate ERα activity. Moreover, ERß knockout studies and receptor distribution analyses in the CNS suggest that this receptor may play a role in the modulation of mood and cognition. In recent years several ERß-specific compounds (selective estrogen receptor beta modulators; SERM-beta) have become available, and research suggests potential utility of these compounds in menopausal symptom relief, breast cancer prevention, diseases that have an inflammatory component, osteoporosis, cardiovascular disease, and inflammatory bowel disease, as well as modulation of mood, and anxiety. Here we demonstrate an antidepressant-like effect obtained using two SERM-beta compounds, SERM-beta1 and SERM-beta2. These compounds exhibit full agonist activity at ERß in a cell based estrogen response element (ERE) transactivation assay. SERM-beta1 and 2 are non-proliferative with respect to breast as determined using the MCF-7 breast cancer cell-based assay and non-proliferative in the uterus as determined by assessing the effects of SERM-beta compounds on immature rat uterine weight and murine uterine weight. In vivo SERM-beta1 and 2 are brain penetrant and display dose dependent efficacy in the murine dorsal raphe assays for induction of tryptophan hydroxylase mRNA and progesterone receptor protein. These compounds show activity in the murine forced swim test and promote hippocampal neurogenesis acutely in rats. Taken together these data suggest that ERß may play an important role in modulating mood and the ERß specific compounds described herein will be useful tools for probing the utility of an ERß agonist for treating neuroendocrine-related mood disturbance and menopausal symptoms.
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Antidepressivos , Receptor beta de Estrogênio/efeitos dos fármacos , RNA Mensageiro/biossíntese , Núcleos da Rafe/enzimologia , Moduladores Seletivos de Receptor Estrogênico/farmacologia , Natação/psicologia , Triptofano Hidroxilase/biossíntese , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , DNA/genética , Relação Dose-Resposta a Droga , Receptor alfa de Estrogênio/efeitos dos fármacos , Feminino , Hipocampo/efeitos dos fármacos , Hipocampo/crescimento & desenvolvimento , Humanos , Imuno-Histoquímica , Hibridização In Situ , Neurogênese/efeitos dos fármacos , Tamanho do Órgão/efeitos dos fármacos , Plasmídeos/genética , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley , Receptores Androgênicos/metabolismo , Receptores de Progesterona/metabolismo , Ativação Transcricional/efeitos dos fármacos , Triptofano Hidroxilase/genética , Útero/anatomia & histologia , Útero/fisiologiaRESUMO
A magnetic recoil spectrometer (MRS) has been built and successfully used at OMEGA for measurements of down-scattered neutrons (DS-n), from which an areal density in both warm-capsule and cryogenic-DT implosions have been inferred. Another MRS is currently being commissioned on the National Ignition Facility (NIF) for diagnosing low-yield tritium-hydrogen-deuterium implosions and high-yield DT implosions. As CR-39 detectors are used in the MRS, the principal sources of background are neutron-induced tracks and intrinsic tracks (defects in the CR-39). The coincidence counting technique was developed to reduce these types of background tracks to the required level for the DS-n measurements at OMEGA and the NIF. Using this technique, it has been demonstrated that the number of background tracks is reduced by a couple of orders of magnitude, which exceeds the requirement for the DS-n measurements at both facilities.
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BACKGROUND: Somatostatin inhibits gall bladder contraction. Impaired gall bladder emptying is associated with gall bladder stone formation. The incidence of cholecystolithiasis is high in patients treated with a somatostatin agonist octreotide, which predominantly interacts with somatostatin receptor subtype 2 (SSTR2). Therefore, it is believed that SSTR2 regulates gall bladder contraction; however, evidence has not been provided. Here, we evaluate the effects of SSTR1-SSTR5-selective agonists on egg yolk-induced gall bladder contraction in mice. METHODS: Homozygous deletion of SSTR2 and SSTR5 was generated by cross-mating of SSTR2(-/-) with SSTR5(-/-) mice. Mice of different genotypes were injected with SSTR1-5-selective agonists or octreotide 15 min before induction of gall bladder emptying by egg yolk. One hour later, gall bladders were removed and weighed. KEY RESULTS: Egg yolk-reduced gall bladder weights in all mice, irrespective of their genotype. Octreotide was the most potent inhibitor of gall bladder emptying in wild-type mice. In contrast, agonists with high selectivity for SSTR2 or SSTR5 inhibited gall bladder emptying by approximately 50-60%, whereas SSTR1-, SSTR3- and SSTR4-selective agonists failed to influence gall bladder contraction. In SSTR2(-/-) mice, octreotide and an SSTR5-selective agonist inhibited gall bladder emptying by approximately 50%, whereas SSTR2-selective agonists were inactive. Octreotide inhibited gall bladder emptying in SSTR5(-/-) mice by approximately 50%, without any effect in SSTR2(-/-)/SSTR5(-/-) mice. CONCLUSIONS & INFERENCES: Our study provides evidence for the role of SSTR2 and SSTR5 in regulating gall bladder emptying in mice.
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Esvaziamento da Vesícula Biliar/fisiologia , Vesícula Biliar/metabolismo , Receptores de Somatostatina/metabolismo , Análise de Variância , Animais , Peso Corporal/genética , Gema de Ovo , Vesícula Biliar/efeitos dos fármacos , Esvaziamento da Vesícula Biliar/efeitos dos fármacos , Fator de Crescimento Insulin-Like I/metabolismo , Camundongos , Camundongos Knockout , Contração Muscular/efeitos dos fármacos , Contração Muscular/fisiologia , Octreotida/farmacologia , Proteínas/metabolismo , Proteinúria/metabolismo , Receptores de Somatostatina/genética , Somatostatina/metabolismoRESUMO
There is continued debate over the factors influencing handedness in captive and wild primates, notably chimpanzees. Previous studies in wild chimpanzees have revealed population-level left handedness for termite fishing. Here we examined hand preferences and performance on a tool use task designed to simulate termite fishing in a sample of 190 captive chimpanzees to evaluate whether patterns of hand use in captive chimpanzees differed from those observed for wild apes. No population-level handedness was found for this task; however, significant sex differences in preference and performance were found, with males showing greater left handedness and poorer performance compared to females. We also found that the hand preferences of offspring were significantly positively correlated with the hand preferences of their mothers. Lastly, older females performed more slowly on the task compared to younger individuals. The overall results neither confirm nor reject previous hypotheses claiming that raising chimpanzees in captivity induces right-handedness, but rather suggest that other factors may account for differences in hand preferences for tool use seen in wild and captive chimpanzees.
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Distinct mechanisms such as humeral immunity in dermatomyositis (DM) and T-cell-mediated cytotoxicity in polymyositis (PM) contribute to the pathology of inflammatory myopathies. In addition, different subsets of macrophages are present in both diseases. Herein, the characteristics of 25F9-positive macrophages in skeletal muscle inflammation are outlined. Muscle biopsies of subjects with DM and PM were studied by immunohistochemical multi-labelling using the late-activation marker 25F9, together with markers characterizing macrophage function including IFN-gamma, iNOS, and TGF-beta. In PM, a robust expression of IFN-gamma, iNOS, and TGF-beta was observed in inflammatory cells. Double- and serial-labelling revealed that a subset of 25F9-positive macrophages in the vicinity of injured muscle fibres expressed iNOS and TGF-beta, but not IFN-gamma. In DM, IFN-gamma, iNOS and TGF-beta were also expressed in inflammatory cells in the endomysium. Double- and serial-labelling studies in DM indicated that 25F9-positive macrophages expressed TGF-beta and to a lesser degree iNOS, but not IFN-gamma. In conclusion, our data suggest that late-activated macrophages contribute to the pathology of inflammatory myopathies.
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Dermatomiosite/fisiopatologia , Macrófagos/fisiologia , Polimiosite/fisiopatologia , Adulto , Antígenos de Diferenciação Mielomonocítica/metabolismo , Criança , Humanos , Imuno-Histoquímica , Interferon gama/metabolismo , Interferon gama/fisiologia , Macrófagos/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico Sintase Tipo II/fisiologia , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta/fisiologiaRESUMO
Synthesis and derivatization of a series of substituted tetrahydrofluorenone analogs giving potent, ERbeta subtype selective ligands are described. Several analogs possessing ERbeta binding affinities comparable to 17beta-estradiol but with greater than 75-fold selectivity over ERalpha are reported.
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Receptor beta de Estrogênio/efeitos dos fármacos , Fluorenos/síntese química , Fluorenos/farmacologia , Linhagem Celular , Cristalografia por Raios X , Receptor alfa de Estrogênio/química , Receptor alfa de Estrogênio/efeitos dos fármacos , Receptor beta de Estrogênio/química , Fluorenos/classificação , Humanos , Ligantes , Modelos Moleculares , Estrutura Molecular , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Autophagy, a highly regulated programme found in almost all eukaryotes, is mainly viewed as a catabolic process that degrades nonessential cellular components into molecular building blocks, subsequently available for biosynthesis at a lesser expense than de novo synthesis. Autophagy is largely known to be regulated by nutritional conditions. Here we show that, in yeast cells grown under nonstarving conditions, autophagy can be induced by mitochondrial dysfunction. Electron micrographs and biochemical studies show that an autophagic activity can result from impairing the mitochondrial electrochemical transmembrane potential. Furthermore, mitochondrial damage-induced autophagy results in the preferential degradation of impaired mitochondria (mitophagy), before leading to cell death. Mitophagy appears to rely on classical macroautophagy machinery while being independent of cellular ATP collapse. These results suggest that in this case, autophagy can be envisioned either as a process of mitochondrial quality control, or as an ultimate cellular response triggered when cells are overwhelmed with damaged mitochondria.
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Trifosfato de Adenosina/metabolismo , Mitocôndrias/fisiologia , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Saccharomyces cerevisiae/fisiologia , Autofagia/fisiologia , Morte Celular/fisiologia , Potencial da Membrana Mitocondrial/fisiologia , Proteínas Mitocondriais/metabolismo , Mutação , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMO
The effects of estrogen receptor (ER) ligands on the stability and transcriptional activity of ERbeta in the breast cancer cell lines MCF-7 and HeLa were examined. We found that ERbeta was degraded in the presence of 17beta-estradiol. Tamoxifen and Faslodex (ICI 182,780) prevented ERbeta receptor destabilization. In contrast to ERalpha, ERbeta degradation was not abolished by inhibitors of the proteasome-mediated protein degradation pathway. Furthermore, single point mutations in helix 12 of the receptor dramatically affected the stability and subsequent transcriptional activation of ERbeta.
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Acetilcisteína/análogos & derivados , Neoplasias da Mama/metabolismo , Estradiol/análogos & derivados , Estradiol/metabolismo , Antagonistas de Estrogênios/metabolismo , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Acetilcisteína/metabolismo , Animais , Linhagem Celular Tumoral , Inibidores de Cisteína Proteinase/metabolismo , Estradiol/farmacologia , Receptor alfa de Estrogênio/química , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/química , Receptor beta de Estrogênio/genética , Feminino , Fulvestranto , Regulação da Expressão Gênica , Genes Reporter , Humanos , Ligantes , Mutação Puntual , Tamoxifeno/metabolismoRESUMO
The Rvs161 and Rvs167 proteins are known to play a role in actin cytokeleton organization and endocytosis. Moreover, Rvs167p functionally interacts with the myosin Myo2p. Therefore, we explored the involvement of the Rvs proteins in vesicle traffic and in cell integrity. The rvs mutants accumulate late secretory vesicles at sites of membrane and cell wall construction. They are synthetic-lethal with the slt2/mpk1 mutation, which affects the MAP kinase cascade controlled by Pkc1p and is required for cell integrity. The phenotype of the double mutants is close to that described for the pkc1 mutant. Synthetic defects for growth are also observed with mutation in KRE6, a gene coding for a glucan synthase, required for cell wall construction. These data support the idea that the Rvs proteins are involved in the late targeting of vesicles whose cargoes are required for cell wall construction.
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Membrana Celular/metabolismo , Proteínas do Citoesqueleto , Proteínas Fúngicas/metabolismo , Proteína Quinase C , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Vesículas Secretórias/metabolismo , Parede Celular/metabolismo , Meios de Cultura , Proteínas Fúngicas/genética , Dosagem de Genes , Genes Fúngicos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas dos Microfilamentos , Microscopia Eletrônica , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação , Fenótipo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/ultraestrutura , Esporos FúngicosRESUMO
We have used a combination of freeze-substitution electron microscopy and specific reaction for polysaccharides to re-evaluate glycogen structures in Saccharomyces cerevisiae. We also used mutant cells devoid of glycogen to confirm the glycogenic nature of the structures described. Previously described cytoplasmic aggregates were confirmed as glycogen granules. Moreover, an original structure was discovered. This is a ring of glycogen surrounding a finger- or pleat-like plasma membrane invagination. This structure could be physiologically significant in terms of channelling glucose to or from glycogen reserves.
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Membrana Celular/química , Glicogênio/ultraestrutura , Saccharomyces cerevisiae/química , Membrana Celular/ultraestrutura , Glicogênio/deficiência , Glicogênio/genética , Saccharomyces cerevisiae/ultraestruturaRESUMO
Extensive development of the structure-activity relationships of a screening lead determined three important pharmacophores for gonadotropin-releasing hormone (GnRH) receptor antagonist activity. Incorporation of the 3,4,5-trimethylphenyl group at the 3-position, 2-(2(S)-azetidinyl)ethoxy group at the 4-position, and N-4-pyrimidinylcarboxamide at the 6-position of the quinolone core resulted in the identification of 4-(2-(azetidin-2(S)-yl)ethoxy)-7-chloro-2-oxo-3-(3,4,5-trimethylphenyl)-1,2-dihydroquinoline-6-carboxylic acid pyrimidin-4-ylamide (1) as a potent antagonist of the GnRH receptor. A 10(4)-fold increase in in vitro binding affinity is observed for the GnRH receptor as compared to the initial screening lead. Compound 1 exhibits nanomolar binding activity and functional antagonism at the human receptor and is 7-fold less active at the rhesus receptor. Intravenous administration of compound 1 to rhesus monkeys results in a significant decrease of the serum levels of downstream hormones, luteinizing hormone (79% decrease in area under the curve) and testosterone (92% decrease in area under the curve), at a dose of 3 mg/kg. Quinolone 1 is a potent nonpeptidyl antagonist for the human GnRH receptor that is efficacious for the suppression of luteinizing hormone and testosterone in primates.
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Azetidinas/síntese química , Quinolonas/síntese química , Receptores LHRH/antagonistas & inibidores , Animais , Azetidinas/química , Azetidinas/farmacocinética , Azetidinas/farmacologia , Ligação Competitiva , Células CHO , Cricetinae , Humanos , Técnicas In Vitro , Macaca mulatta , Hipófise/metabolismo , Quinolonas/química , Quinolonas/farmacocinética , Quinolonas/farmacologia , Ensaio Radioligante , Ratos , Relação Estrutura-AtividadeRESUMO
N-Substituted nipecotic and iso-nipecotic amides of beta-methylTrpLys tert-butyl ester were found to be novel, selective and potent agonists of the somatostatin subtype-2 receptor in vitro. For example iso-nipecotic amide 8a showed high hsst2 binding affinity (Ki = 0.5 nM) and good selectivity (h5/h2 = 832).
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Ácidos Nipecóticos/metabolismo , Receptores de Somatostatina/agonistas , Animais , Técnicas de Química Combinatória , Humanos , Isomerismo , Ácidos Nipecóticos/síntese química , Oligopeptídeos/síntese química , Oligopeptídeos/metabolismo , Ligação Proteica , Receptores de Somatostatina/metabolismo , Relação Estrutura-AtividadeRESUMO
Magnetoencephalography (MEG) measured subjects' brain responses during a lexical decision task. The words employed come from six frequency categories, which were defined in terms of a linear decrease in log-frequency. Although frequency effects in reaction-time are well-documented in studies of lexical access, a neural component whose latency predicts reaction time has not been discovered. This study identifies an MEG component (the M350) whose latency mirrors the frequency-effect.
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Magnetoencefalografia , Fala/fisiologia , Adulto , Comportamento/fisiologia , Tomada de Decisões/fisiologia , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Tempo de Reação/fisiologiaRESUMO
Twenty-five avermectin analogs were assessed in a mouse seizure model. The ED(50) against pentylenetetrazole-induced tonic seizures ranged from 0.48 mg/kg (L-676,893) to >160 mg/kg (L-685,869) cf. 0. 26 mg/kg for diazepam. Although avermectins are without acute toxic effects, they have been historically shown to have relative low LD(50) values in mammals. The mechanisms involved in the anticonvulsant effect and the toxicity were investigated. A series of avermectin analogs displaced [(3)H]ivermectin binding to rat brain membranes and recombinant GABA(A) receptors (alpha1beta3gamma2-subtype) with the same affinities, strongly suggesting that [(3)H]ivermectin labels the GABA(A) receptor in rodent brain. Avermectins, which were anticonvulsant, were also potent inhibitors of [(3)H]ivermectin binding in rat brain. However, the rank order for anticonvulsant activity did not parallel the rank order for affinity at the [(3)H]ivermectin site and it was reasoned that avermectins may have differential affinity or efficacy at subtypes of the GABA(A) receptor. All the active compounds tested potentiated the effects of GABA at recombinant GABA(A) receptors in oocytes and at native cortical GABA(A) receptors and the efficacy of avermectins at the GABA(A) receptor correlated best with their anticonvulsant potency. Although avermectins weakly inhibited [(3)H]strychnine binding in rat spinal cord, and inhibited glycine responses on primary cultured cortical neurons, activity at glycine receptors did not correlate with either anticonvulsant activity or toxicity. Because both anticonvulsant activity and toxicity correlated best with activity at GABA(A) receptors, it is unlikely that these effects can be separated, which may contraindicate the potential use of avermectins as anticonvulsants.
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Anticonvulsivantes/farmacologia , Ivermectina/análogos & derivados , Receptores de GABA-A/efeitos dos fármacos , Animais , Células Cultivadas , Córtex Cerebral/efeitos dos fármacos , Feminino , Ivermectina/efeitos adversos , Ivermectina/farmacologia , Masculino , Camundongos , Ratos , Receptores de GABA-A/química , Receptores de GABA-A/fisiologia , Receptores de Glicina/efeitos dos fármacos , Proteínas Recombinantes/efeitos dos fármacos , XenopusRESUMO
High affinity, subtype selective non-peptide agonists of somatostatin receptor subtypes 1-5 were identified in combinatorial libraries constructed based on molecular modeling of known peptide agonists. Simultaneous traditional chemical synthesis yielded an additional series of somatostatin subtype-2 receptor (SSTR2) selective agonists. These compounds have been used to further define the physiological functions of the individual somatostatin receptor subtypes. In vitro experiments demonstrated the role of the SSTR2 in inhibition of glucagon release from mouse pancreatic alpha-cells and the somatostatin subtype-5 receptor (SSTR5) as a mediator of insulin secretion from pancreatic beta-cells. Both SSTR2 and SSTR5 regulated growth hormone release from the rat anterior pituitary gland. In vivo studies performed with SSTR2 receptor selective compounds demonstrated effective inhibition of pulsatile growth hormone release in rats. The SSTR2 selective compounds also lowered plasma glucose levels in normal and diabetic animal models. The availability of high affinity, subtype selective non-peptide agonists for each of the somatostatin receptors provides a direct approach to defining their physiological function both peripherally and in the central nervous system.
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Amidas/química , Indóis/química , Naftalenos/química , Nitrobenzenos/química , Piridinas/química , Receptores de Somatostatina/agonistas , Animais , Benzimidazóis/química , Células CHO , Clonagem Molecular , Técnicas de Química Combinatória , Cricetinae , Glucagon/metabolismo , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Proteínas de Membrana , Receptores de Somatostatina/química , Receptores de Somatostatina/genética , Somatostatina/agonistasRESUMO
Somatostatin (SRIF) controls many physiological and pathological processes in the central nervous system but the respective roles of the five receptor isotypes (sst1-5) that mediate its effects are yet to be defined. In the present study, we attempted to identify functions of the sst2 receptor using mice with no functional copy of this gene (sst2 KO mice). In contrast with control 129Sv/C57Bl6 mice, sst2 mRNA was no longer detectable in the brain of sst2 KO mice; 125I-labeled Tyr0DTrp8-SRIF14 binding was also greatly reduced in almost all brain structures except for the hippocampal CA1 area, demonstrating that sst2 accounts for most SRIF binding in mouse brain. Invalidation of this subtype generated an increased anxiety-related behaviour in a number of behavioural paradigms, while locomotor and exploratory activity was decreased in stress-inducing situations. No major motor defects could be detected. sst2 KO mice also displayed increased release of pituitary ACTH, a main regulator of the stress response. Thus, somatostatin, via sst2 receptor isotype pathways, appears involved in the modulation of locomotor, exploratory and emotional reactivity in mice.