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1.
Phys Biol ; 14(5): 055002, 2017 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-28698411

RESUMO

While plant growth is well known to rely on turgor pressure, it is challenging to quantify the contribution of turgor pressure to plant cell rheology. Here we used a custom-made micro-rheometer to quantify the viscoelastic behavior of isolated plant cells while varying their internal turgor pressure. To get insight into how plant cells adapt their internal pressure to the osmolarity of their medium, we compared the mechanical behavior of single plant cells to that of a simple, passive, pressurized shell: a soccer ball. While both systems exhibited the same qualitative behavior, a simple mechanical model allowed us to quantify turgor pressure regulation at the single cell scale.


Assuntos
Pressão Osmótica , Células Vegetais , Fenômenos Biomecânicos , Elasticidade , Modelos Biológicos , Reologia , Viscosidade
2.
Brain Res ; 563(1-2): 339-44, 1991 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-1786549

RESUMO

Circadian effects on basal and stress-induced Fos-like immunoreactivity (IR) in the paraventricular nucleus of the hypothalamus (PVN), the habenula (Hab) and the posterior paraventricular nucleus of the thalamus (PVN-Thal) were examined. Stress induced a significant increase in the number of Fos-like IR cells within all 3 brain regions. In the Hab, expression was localized specifically to the medial region of the lateral Hab. No differences between the effects of daytime vs nighttime stress on numbers of Fos-like IR cells in the PVN and PVP-Thal were observed. Significantly fewer Fos-like IR cells were observed, however, in the lateral habenula of nighttime vs daytime non-stressed controls, resulting in a significantly greater percentage increase in Fos-like IR in the lateral habenula following nighttime vs daytime stress.


Assuntos
Ritmo Circadiano/fisiologia , Proteínas Oncogênicas v-fos/metabolismo , Núcleo Hipotalâmico Paraventricular/metabolismo , Estresse Psicológico/metabolismo , Núcleos Talâmicos/metabolismo , Tálamo/metabolismo , Animais , Regulação da Expressão Gênica , Masculino , Proteínas Oncogênicas v-fos/imunologia , Ratos , Ratos Endogâmicos , Restrição Física
3.
Neurosci Lett ; 126(2): 113-8, 1991 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-1922920

RESUMO

An immobilisation stress (IS) of 2 h applied to rats at the beginning of the dark period (12 h), i.e. when the animals are more active, induces during the 10 consecutive h a significant rebound (+92%) of paradoxical sleep (PS) while slow-wave sleep state (SWS) is poorly affected. Two h of sleep deprivation, also applied at the beginning of the dark period and realized either by the platform technique or by maintaining the animals awake with gentle handling, do not affect significantly subsequent SWS and PS. Finally, when repetitive IS are inflicted to the animals (one IS of 2 h every 3 days) an attenuation of the PS rebound is observed. These data suggest that a qualitative aspect of the waking state as in an intense stressful situation might be the source of a hormonal process inducing a PS excess.


Assuntos
Imobilização , Sono REM/fisiologia , Estresse Fisiológico/fisiopatologia , Animais , Manobra Psicológica , Masculino , Ratos , Ratos Endogâmicos , Privação do Sono/fisiologia , Estresse Fisiológico/etiologia
4.
Brain Res Mol Brain Res ; 8(4): 325-9, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2176710

RESUMO

A messenger ribonucleic acid (mRNA) homologous to the transcript that encodes vasopressin (VP) was detected in the neurointermediate lobe (NIL) of the rat pituitary. The abundance of this transcript is approximately 1/100th the amount detected in the hypothalamus. In rats drinking 2% NaCl-water for 0,2,4, or 10 days, or for 10 days and then tap water for 14 days, the levels of VP mRNA in the NIL were altered in a fashion that paralleled changes in the hypothalamus.


Assuntos
Neuro-Hipófise/química , RNA Mensageiro/análise , Vasopressinas/genética , Animais , Masculino , Hibridização de Ácido Nucleico , Ratos
5.
J Chem Neuroanat ; 3(4): 297-308, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2168715

RESUMO

After the recent demonstration of the facilitatory effect exerted by corticotropin-like intermediate lobe peptide (CLIP or adrenocorticotropic hormone (ACTH) 18-39) on paradoxical sleep in the rat (Chastrette and Cespuglio, 1985), we undertook the production of monoclonal antibodies against this peptide. Wistar rats were immunized against CLIP and their spleen cells fused with mouse myeloma cells. After recloning, 25 supernatants were found to give positive immunohistochemical reactions in the rat brain. In immunohistochemical tests performed by preabsorption, the 25 supernatants presented similar properties, i.e. recognized CLIP, ACTH (1-39) and ACTH (25-39), but not ACTH (1-24) and the C-terminal fragment (34-39). We assume that the epitope(s) recognized by the 25 supernatants is (are) located between the amino-acids Asn25 and Ala34 of the CLIP molecule. The immunoreactivity observed in the rat brain and hypophysis with this antibody was distributed with a pattern quite similar to that described for anti-ACTH antibodies. A main group of immunoreactive cell bodies was located in the mediobasal hypothalamus and a small group in the nucleus of the solitary tract. Immunoreactive fibres were distributed from the olfactory nucleus to the spinal cord and formed particularly rich networks in the hypothalamus and preoptic area. Among other locations, immunoreactive axons were also present in the brainstem centres involved in the control of the sleep-waking cycle, which is in accordance with the influence of CLIP on paradoxical sleep. Using Abercrombie's formula, the number of immunoreactive cells in the mediobasal hypothalamus was estimated at about 3000 neurons. We conclude that our monoclonal anti-CLIP antibody can be considered as a good marker of proopiomelanocortin neurons.


Assuntos
Hormônio Adrenocorticotrópico/análise , Anticorpos Monoclonais , Química Encefálica , Hipotálamo/citologia , Fragmentos de Peptídeos/análise , Hipófise/análise , Hormônio Adrenocorticotrópico/imunologia , Animais , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Contagem de Células , Peptídeo da Parte Intermédia da Adeno-Hipófise Semelhante à Corticotropina , Imunofluorescência , Hibridomas/imunologia , Masculino , Neurônios/análise , Neurônios/citologia , Fragmentos de Peptídeos/imunologia , Ratos , Ratos Endogâmicos , Distribuição Tecidual
6.
Neuropeptides ; 15(2): 61-74, 1990 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1981927

RESUMO

The sleep-wake effects of the proopiomelanocortin (POMC)-derived peptides, i.c.v. injected, are reported. Adrenocorticotropic hormone (ACTH, 1 microgram) induces an awakening effect, while its two derivatives, desacetyl-alpha-MSH (des-alpha-MSH, 1ng) and corticotropin-like intermediate lobe peptide (CLIP, 10 ng), are respectively able to increase slow wave sleep (SWS) and paradoxical sleep (PS); the hypnogenic effect of CLIP is also observed in hypophysectomized rats. Furthermore, two hypothalamic factors known to be involved in the control of POMC derivatives were also injected; MSH inhibiting Factor (MIF) does not influence the vigilance states, while Corticotropin Releasing Factor (CRF, 1 microgram) increases the waking state. Finally, some preliminary results, obtained with a restraint stress and suggesting a possible interrelation between stress, sleep and POMC derivatives, are discussed.


Assuntos
Hormônio Adrenocorticotrópico/farmacologia , Fragmentos de Peptídeos/farmacologia , Pró-Opiomelanocortina/farmacologia , Sono/efeitos dos fármacos , Animais , Bacitracina/farmacologia , Cloranfenicol/farmacologia , Peptídeo da Parte Intermédia da Adeno-Hipófise Semelhante à Corticotropina , Hormônio Liberador da Corticotropina/farmacologia , Hormônio Inibidor da Liberação de MSH/farmacologia , Masculino , Ratos , Restrição Física , Fases do Sono/efeitos dos fármacos , Estresse Fisiológico/fisiopatologia , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
7.
Neuropeptides ; 15(2): 75-88, 1990 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1964203

RESUMO

Apomorphine (Apo), a D1/D2 Dopamine (DA) agonist, at high doses (500 micrograms/kg) induces a short-lasting insomnia, antagonized by a secondary injection of corticotropin-like intermediate lobe peptide (CLIP, 10 ng); these effects are also observed with hypophysectomized (hypoX) rats. The administration of the serotonin (5-HT) agonist 8-hydroxy-2-di-n-propylamino-tetralin (8-OHDPAT, 0.3 mg/kg) induces also an insomnia which, unlike Apo, is followed by a significant PS rebound. CLIP, again, antagonizes the 8-OHDPAT-induced insomnia. Finally, Bromocriptine (5 mg/kg), an agonist for both DA and 5-HT, induces first an insomnia (antagonized by CLIP), followed by a PS rebound; these effects persist in hypoX rats.


Assuntos
Fragmentos de Peptídeos/farmacologia , Pró-Opiomelanocortina/farmacologia , Sono/efeitos dos fármacos , 8-Hidroxi-2-(di-n-propilamino)tetralina , Hormônio Adrenocorticotrópico/farmacologia , Animais , Apomorfina/antagonistas & inibidores , Apomorfina/farmacologia , Apomorfina/toxicidade , Bromocriptina/farmacologia , Peptídeo da Parte Intermédia da Adeno-Hipófise Semelhante à Corticotropina , Dopamina/fisiologia , Antagonistas de Dopamina , Hipóxia/fisiopatologia , Masculino , Ratos , Receptores Dopaminérgicos/efeitos dos fármacos , Receptores Dopaminérgicos/fisiologia , Serotonina/fisiologia , Distúrbios do Início e da Manutenção do Sono/induzido quimicamente , Fases do Sono/efeitos dos fármacos , Tetra-Hidronaftalenos/farmacologia , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
8.
Exp Brain Res ; 80(1): 121-8, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-1694135

RESUMO

In the present work, differential pulse voltammetry (DPV) measurements of the extracellular fraction of 5-hydroxyindole compounds were performed in rats under long-term chronic conditions. In the nucleus Raphe Dorsalis (n.RD), the voltammetric signal measured at +300 mv (peak 3) disappeared completely 70 to 90 min after injection of Clorgyline (10 mg/kg), a monoamine oxidase inhibitor type A (MAOI-A); the signal measured in such conditions is thus dependent upon extracellular 5-hydroxyindoleacetic acid (5-HIAA peak 3). Deprenyl, an MAOI type B, at the same dose, induced only a slight increase in peak 3 height; according to the fact that MAO-B is selectively located in the 5-HT neurons and since their inhibition does not decrease 5-HIAA peak 3 nor the endogenous 5-HIAA content as measured with High Performance Liquid Chromatography (HPLC), 5-HIAA measured with DPV in the extracellular fluid of untreated animals might come from 5-HT released and metabolized by MAO-A outside the 5-HT neurons. In animals implanted for measurements of both voltammetric and polygraphic parameters, the 5-HIAA peak 3 measured mainly in the anterior and ventral part of the n.RD exhibited large increases in its height during slow-wave sleep (SWS: +39%) and paradoxical sleep (PS = +71%) as compared to the waking state (W = 100%); these variations could reflect the dendritic release of 5-HT. In the Caudate nucleus (n.Cd) the same voltammetric signal presented reverse fluctuations, i.e. an increase during W and a decrease during SWS and PS.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Ácido Hidroxi-Indolacético/metabolismo , Núcleos da Rafe/fisiologia , Serotonina/metabolismo , Sono/fisiologia , Vigília/fisiologia , Hormônio Adrenocorticotrópico/farmacologia , Animais , Núcleo Caudado/metabolismo , Núcleo Caudado/fisiologia , Clorgilina/farmacologia , Peptídeo da Parte Intermédia da Adeno-Hipófise Semelhante à Corticotropina , Masculino , Inibidores da Monoaminoxidase/farmacologia , Fragmentos de Peptídeos/farmacologia , Núcleos da Rafe/metabolismo , Ratos
9.
C R Acad Sci III ; 307(18): 817-23, 1988.
Artigo em Francês | MEDLINE | ID: mdl-2464425

RESUMO

Differential pulse voltammetry was used for 5-hydroxyindoleacetic acid (5-HIAA) detection in the rat caudate (n. Cd) and Raphe Dorsalis (n. RD) nuclei, in chronic experimental conditions. In the anterior and ventral part of n. RD, large increases in the extracellular concentrations of 5-HIAA were reported during slow wave sleep (SWS) and paradoxical sleep (PS) whereas a decrease occurred during waking. These variations could reflect the dendritic release of serotonin. In n. Cd, opposite variations of the extracellular concentrations of 5-HIAA were observed i.e. increase during waking state and decrease during SWS and PS.


Assuntos
Axônios/metabolismo , Espaço Extracelular/metabolismo , Ácido Hidroxi-Indolacético/metabolismo , Terminações Nervosas/metabolismo , Núcleos da Rafe/metabolismo , Sono/fisiologia , Vigília/fisiologia , Animais , Núcleo Caudado/metabolismo , Eletrodos , Masculino , Pargilina/farmacologia , Núcleos da Rafe/efeitos dos fármacos , Ratos , Serotonina/metabolismo
10.
Exp Brain Res ; 64(3): 589-95, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-2433140

RESUMO

Differential pulse voltammetry was performed in rats chronically implanted with carbon fiber electrodes in the caudate (n.Cd) and raphe dorsalis (n.RD) nuclei. The electrochemical signal obtained at the +300 mV potential (peak 3) in animals implanted for more than one week (long term chronic conditions, greater than 7 days) could be dependent upon the extracellular fraction of 5-hydroxyindolacetic acid (5-HIAA) since a single injection of Pargyline is sufficient to suppress it in n.Cd and n.RD. This result was obtained despite the tendency of Pargyline to increase n.Cd and n.RD endogenous concentrations of Uric Acid (UA) measured by High Performance Liquid Chromatography (HPLC). In contrast, in animals implanted for less than one week (short term chronic conditions, less than 7 days) peak 3 recorded in the same structure could be dependent upon extracellular fractions of 5-HIAA and UA since consecutive injections of Pargyline and Allopurinol are necessary to suppress this signal. The source of extracellular UA measured in brain by voltammetry, in such short term chronic conditions, might result from surgical trauma.


Assuntos
Núcleo Caudado/análise , Técnicas de Química Analítica/instrumentação , Eletroquímica/instrumentação , Ácido Hidroxi-Indolacético/análise , Núcleos da Rafe/análise , Ácido Úrico/análise , Animais , Carbono , Cromatografia Líquida de Alta Pressão , Microeletrodos , Oxirredução , Ratos , Análise Espectral
11.
Neurosci Lett ; 62(3): 365-70, 1985 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-3005923

RESUMO

The effects of i.c.v. injections of different proopiomelanocortin-derived peptides were tested on the rat sleep-waking cycle: adrenocorticotropic hormone (ACTH) had no effect. In contrast, administration of two ACTH-derived peptides was followed by a selective and significant increase of each sleep state: desacetyl-alpha-melanocyte-stimulating hormone induced an increase of slow-wave sleep, while corticotropin-like intermediate lobe peptide was followed by an increase of paradoxical sleep. Both alpha-melanocyte-stimulating hormone in its acetylated form and alpha-endorphin were inactive.


Assuntos
Pró-Opiomelanocortina/farmacologia , Fases do Sono/efeitos dos fármacos , alfa-MSH/análogos & derivados , Hormônio Adrenocorticotrópico/farmacologia , Animais , Nível de Alerta/efeitos dos fármacos , Endorfinas/farmacologia , Masculino , Hormônios Estimuladores de Melanócitos/farmacologia , Fragmentos de Peptídeos/farmacologia , Ratos , Ratos Endogâmicos , Sono/efeitos dos fármacos , Sono REM/efeitos dos fármacos , Fatores de Tempo
12.
C R Acad Sci III ; 301(19): 817-22, 1985.
Artigo em Francês | MEDLINE | ID: mdl-2417672

RESUMO

The electrochemical signal obtained at the +300 mV potential (peak 3) in rats implanted for more than one week could be dependent upon extracellular fraction of 5-hydroxyindolacetic acid (5-HIAA) since a single injection of Pargyline is sufficient to suppress it in caudate and raphe dorsalis nuclei. In contrast, in rats implanted for less than one week, this signal could be dependent upon extracellular fractions of 5-HIAA and uric acid since consecutive injections of Pargyline and Allopurinol are necessary to suppress it.


Assuntos
Química Encefálica , Ácido Hidroxi-Indolacético/análise , Ácido Úrico/análise , Animais , Cromatografia Líquida de Alta Pressão , Eletrodos Implantados , Espaço Extracelular , Masculino , Oxirredução , Potenciometria/métodos , Ratos , Fatores de Tempo
13.
C R Acad Sci III ; 301(10): 527-30, 1985.
Artigo em Francês | MEDLINE | ID: mdl-3004676

RESUMO

In the rat, the intraventricular administration of ACTH (adrenocorticotropic hormone) has no effect upon the sleep-waking cycle. However, administration of two ACTH-derived peptides is followed by a selective and significant increase of each sleep state: Des-alpha-MSH (Des-acetyl-alpha-melanocyte stimulating hormone) administration induces an increase of slow wave sleep, while CLIP (corticotropin-like intermediate lobe peptide) is followed by an increase of paradoxical sleep.


Assuntos
Hormônio Adrenocorticotrópico/farmacologia , Hipnóticos e Sedativos/farmacologia , Fragmentos de Peptídeos/farmacologia , Sono/efeitos dos fármacos , alfa-MSH/análogos & derivados , Animais , Peptídeo da Parte Intermédia da Adeno-Hipófise Semelhante à Corticotropina , Masculino , Ratos
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