RESUMO
Our understanding of the regulation of vascular development has exploded over the past decade. Prior to this time, our knowledge of vascular development was primarily based on classic descriptive studies. The identification of stem cells, lineage markers, specific growth factors and their receptors, and signalling pathways has facilitated a rapid expansion in information regarding details of the mechanisms that govern development of the vascular system.
Assuntos
Endotélio Vascular/embriologia , Células-Tronco Mesenquimais/citologia , Músculo Liso Vascular/embriologia , Animais , Diferenciação Celular , Linhagem da Célula , Proliferação de Células , Células Endoteliais/citologia , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Efrinas/metabolismo , Proteínas Hedgehog/metabolismo , Humanos , Músculo Liso Vascular/citologia , Pericitos/citologia , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Several cytokines have been involved in the regulation of Sertoli cell function. Further investigations are required to elucidate the role of interleukin-1beta (IL1beta) in Sertoli cell physiology. Twenty-day-old rat Sertoli cell cultures were used to investigate a possible role of IL1beta in the regulation of gamma-glutamyl transpeptidase (gammaGTP) and to elucidate the signaling pathway utilized by this cytokine. GammaGTP is a membrane-bound enzyme that has been involved in amino acid transport across the plasma membrane and in protection from oxidative stress through its importance in the regulation of glutathione levels. Previous studies suggested that IL1beta stimulates NO biosynthesis in other cell types. Therefore, we investigated whether IL1beta modified the level of nitrite, a stable metabolite of NO, in Sertoli cells. Dose-response curves to IL1beta for gammaGTP activity and nitrite production were observed. The increments observed in gammaGTP activity and nitrite production were partially and completely blocked by simultaneous treatment with the NO synthase inhibitor aminoguanidine. Treatment of Sertoli cell cultures with the NO donors sodium nitroprusside and S-nitroso-N-acetylpenicillamine resulted in an increase in gammaGTP activity. The presence of neural, endothelial, and inducible isoforms of NO synthase (NOS) was investigated by a immunohistochemical technique using specific antibodies. The 2 constitutive isoforms were present under basal conditions, and the inducible protein appeared in IL1beta-treated cultures. Finally, translocation of NF-kappaB p65 subunit to the nucleus in IL1beta-treated cultures was observed. These findings suggest that the action of IL1beta on Sertoli cell gammaGTP activity is partially mediated via activation of NF-kappaB and increments in iNOS and cellular production of NO.
Assuntos
Interleucina-1/farmacologia , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico/biossíntese , Células de Sertoli/fisiologia , gama-Glutamiltransferase/metabolismo , Animais , Células Cultivadas , Humanos , Isoenzimas/metabolismo , Cinética , Masculino , NF-kappa B/metabolismo , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , Estresse Oxidativo , Penicilamina/análogos & derivados , Penicilamina/farmacologia , Transporte Proteico , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/farmacologia , S-Nitroso-N-Acetilpenicilamina , Células de Sertoli/citologia , Células de Sertoli/efeitos dos fármacos , Transdução de SinaisRESUMO
We have explored whether lipopolysaccharide (LPS, endotoxin) induces pancreatic injury on pancreatic acinar cells both in vivo and in vitro. Wistar male rats were treated with four intraperitoneal injections of 10 mg/kg LPS, and AR4-2J cells were exposed to increasing doses of LPS. Expression of pancreatitis-associated-protein (PAP) mRNA was strongly induced in AR4-2J cells exposed to LPS, while amylase mRNA was reduced. LPS also induced apoptosis and expression of TNF-alpha, IL-1beta, and IL-8 mRNA in AR4-2J cells. The in vivo effect of LPS showed structural signs of cellular damage, including numerous cytoplasmic vacuoles, severe nuclear alterations, and high expression of PAP mRNA. This study demonstrated that LPS induced pancreatic damage by directly affecting the pancreatic acinar cells. The role of LPS in the pathophysiology of acute pancreatitis may be partly due to the effect LPS has on the acinar cell.
Assuntos
Antígenos de Neoplasias , Biomarcadores Tumorais , Lectinas Tipo C , Lipopolissacarídeos/toxicidade , Pâncreas/efeitos dos fármacos , Pancreatite/fisiopatologia , Síndrome de Resposta Inflamatória Sistêmica/fisiopatologia , Doença Aguda , Proteínas de Fase Aguda/genética , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Expressão Gênica/efeitos dos fármacos , Humanos , Injeções Intraperitoneais , Interleucina-1/genética , Interleucina-8/genética , Masculino , Pâncreas/patologia , Pâncreas/fisiopatologia , Pancreatite/induzido quimicamente , Pancreatite/patologia , Proteínas Associadas a Pancreatite , RNA Mensageiro/genética , Ratos , Ratos Wistar , Síndrome de Resposta Inflamatória Sistêmica/patologia , Fator de Necrose Tumoral alfa/genéticaRESUMO
Vizcachas (Lagostomus maximus maximus, Chinchillidae) are nocturnal rodents living in burrows in many regions of Argentina, Bolivia, and Chile. We have studied the eye of the vizcacha using several light and electron microscopic procedures, with the purpose of understanding the role of vision in the behavior of this species. Our observations demonstrated an avascular, rod-rich retina, with a specialized region spanning through most of the equator of the eye. In this central band, all neural retinal layers exhibited a high cell density, whereas the photoreceptor layer was characterized by the presence of very long rods. In addition, the central region was associated with a distinct pigmentation pattern, including scarce granulation of the pigment epithelium, low pigmentation of the choroid, and the selective attachment of suprachoroidal cells to the inner scleral surface. These central modifications probably form the structural basis of a reflecting tapetum. The eye of the vizcacha received both long and short ciliary vessels, and a specialized cilio-sclero-choroidal vascular network appeared at the equatorial region. Our findings suggest that the equatorial region of the eye of the vizcacha could be a highly sensitive light detector related to foraging behaviors during crepuscular or nocturnal hours.
Assuntos
Olho/anatomia & histologia , Roedores/anatomia & histologia , Visão Ocular/fisiologia , Animais , Corioide/anatomia & histologia , Masculino , Microscopia Eletrônica de Varredura , Células Fotorreceptoras/ultraestrutura , Retina/anatomia & histologia , Retina/ultraestrutura , Pigmentos da Retina/análise , Células Fotorreceptoras Retinianas Bastonetes/ultraestrutura , Esclera/anatomia & histologia , Especificidade da EspécieRESUMO
It has been postulated that testosterone secretion is partially regulated by signals from the spermatic nerves. To further examine this hypothesis in vivo, the superior (SSN) or the inferior (ISN) spermatic nerves were stimulated electrically (varying intensity, 25 Hz, 0.2 msec, 10 min) in anesthetized cats, determining the testosterone concentration and the blood flow in the spermatic vein. In some additional experiments arterial blood was sampled, and norepinephrine (NE) output was calculated. Stimulation of the SSN (25-35 V) increased the testosterone concentration in spermatic vein blood (P < 0.01 compared with prestimulation levels). The response varied among animals, reaching a 50-100% increase in some animals, whereas in others it ranged from almost undetectable to more than 10 ng/100 g x min. Under the same experimental conditions, the NE output increased from 135.4 +/- 99 to 1614.2 +/- 347 pg/ml (P < 0.01), and spermatic blood flow decreased from 24.1 +/- 1.42 to 20.2 +/- 1.65 ml/min x 100 g (P < 0.05) during nerve stimulation. By contrast, stimulation of the ISN (25-35 V) modified neither the testosterone concentration, the NE output, nor the blood flow in the spermatic vein. High intensity stimulation (36-70 V) of each spermatic nerve evoked different vascular and hormonal effects. SSN activation induced a marked decrease in spermatic blood flow during stimulation and an increase in the testosterone response, whereas ISN activation resulted only in an enhanced spermatic blood flow. Our results suggest that testosterone secretion, although mainly dependent on gonadotropin secretion, could be further regulated by neural inputs from the SSN acting directly or alternatively through changes in blood flow. It would appear that the SSN mainly supplies the vasoconstrictor fibers to the testis, whereas the ISN provides vasodilator fibers.
Assuntos
Cordão Espermático/irrigação sanguínea , Cordão Espermático/inervação , Testículo/inervação , Testosterona/metabolismo , Animais , Gatos , Estimulação Elétrica , Masculino , Fluxo Sanguíneo Regional , Testículo/irrigação sanguíneaRESUMO
We have made an immunohistochemical study of the vomeronasal (VN) complex of 12-day-old rats to characterize the innervation of its blood vessels. The VN complex can be subdivided into rostral, middle and caudal segments, each one with a particular vascularization pattern. Several small vessels were associated with the rostral segment, whereas a large venous sinus ran along the middle and caudal segments. Immunostaining for alpha-smooth muscle actin demonstrated that the muscular sheath was asymmetric, with more cells layers in its lateral than in its medial walls. Nerves were demonstrated with antisera against protein gene product 9.5 (PGP), and against several molecules associated with specific classes of nerve fibers: the C-terminal peptide of neuropeptide Y (CPON), calcitonin gene-related peptide (CGRP), substance P (SP), galanin (GAL), vasoactive intestinal peptide (VIP) and neuronal nitric oxide synthase (NOS). The latter, was also studied with NADPH-diaphorase. Vascular associated fibers exhibited NOS-, CPON-, GAL-, CGRP-, SP- and VIP-immunoreactivity. Only the vessels of the rostral segment showed VIP-immunoreactive fibers. Each wall of the venous sinus exhibited different types of nerve fibers. CPON-, GAL-, CGRP- and SP-immunoreactive fibers concentrated in the medial wall, whereas NOS-immunoreactive ones concentrated in the lateral wall. This distribution of vascular fibers, plus the presence of sensory fibers exhibiting CGRP-, SP- and GAL-immunoreactivity within the pseudostratified epithelium of the VN tube, would be relevant to understand the operation of the pumping mechanism regulating influx and efflux from the VN tube.
Assuntos
Vasos Sanguíneos/inervação , Fibras Nervosas/química , Neuropeptídeos/análise , Órgão Vomeronasal/irrigação sanguínea , Animais , Feminino , Histocitoquímica , Imuno-Histoquímica , Masculino , Ratos , Ratos Sprague-Dawley , Órgão Vomeronasal/inervaçãoRESUMO
Since nitric oxide has been found to control the function of many organs of the body by the non-adrenergic, non-cholinergic branch of the autonomic nervous system, we hypothesized that it might play a role in salivary secretion. Therefore, we investigated the distribution of nitric oxide synthase (NOS) throughout the submaxillary gland and also studied the ability of inhibitors of NOS to interfere with salivation induced by a cholinergic agonist, metacholine, and by a polypeptide, substance P. The secretory responses were determined in rats anesthetized with chlorolose following intravenous injection of the various pharmacological agents. There was no basal flow of saliva and dose-response curves were obtained by sequential intravenous injection of increasing doses of the drugs. Then, in the same animal, the same dose-response curves were performed in the presence of NOS inhibitors. L-Nitro-arginine-methyl-ester (L-NAME; 20 mg/kg) produced an over 50% inhibition of the dose-related salivation induced by metacholine. Similar results were produced with L-NG-monomethyl-L-arginine (L-NMMA; 5 mg/kg). The salivation induced by much lower molar doses of substance P was dramatically greater than that obtained with metacholine. The response to substance P was almost completely inhibited by L-NMMA at the lowest dose (0.3 mg/kg), but at higher doses (1 mg/kg), the inhibition was only around 60% and at the highest dose (3 mg/kg) only about 20%. In control rats, there were roughly equal amounts of calcium-dependent and calcium-independent NOS in the gland at this time. At the end of the experiment, the effect of the inhibitor of NOS, L-NMMA, on the NOS activity in the submandibular gland was determined. At this time, the Ca2+-dependent NOS was decreased and the Ca2+-independent NO was increased. The prior injection of L-NMMA reduced calcium-dependent NOS activity by approximately 70% but calcium-independent activity by only 30%. These results indicate that, at least at the end of the experiment, the blockade of NOS imposed by NMMA was incomplete. This could account in part for the failure of the inhibitors to block completely the stimulatory effect of the two secretagogues. Analysis of the distribution of NOS in the salivary gland revealed that it was not present in the acinar cells, but in neural terminals within the gland and also in the ductile system which contained neural (n) NOS in the apical membrane of the excretory and striated ducts, the cytoplasm of granular convoluted tubules and, to a lesser extent, in the cytoplasm of excretory and striated ducts. Macrophage (inducible) NOS was also found not only in the macrophages, but also in the tubules and ducts. Since drugs were used that would act on the receptors in the gland, the role of NO in our conditions is probably mediated by nNOS and iNOS in the ductile and tubular structures. Since iNOS would already be active, it is unlikely to play a role in this acute secretory activity. Rather the nNOS in these non-neural cells is probably activated by muscarinic or K1 receptors by metacholine and substance P, respectively, leading to an increase in intracellular free calcium that activates NOS leading to the generation of cGMP that opens ion channels to initiate the secretory process.
Assuntos
Óxido Nítrico/fisiologia , Saliva/metabolismo , Glândulas Salivares/metabolismo , Animais , Cálcio/metabolismo , Inibidores Enzimáticos/farmacologia , Masculino , Cloreto de Metacolina/farmacologia , Agonistas Muscarínicos/farmacologia , NADPH Desidrogenase/metabolismo , NG-Nitroarginina Metil Éster/farmacologia , Proteínas do Tecido Nervoso/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo I , Óxido Nítrico Sintase Tipo II , Ratos , Ratos Wistar , Saliva/efeitos dos fármacos , Glândulas Salivares/efeitos dos fármacos , Glândulas Salivares/enzimologia , Substância P/farmacologia , ômega-N-Metilarginina/farmacologiaRESUMO
An immunohistochemical study of the nasal mucosa was done in pediatric patients attending an otorhinolaringology (ORL) clinic. The goal was a comparison between vascular innervation in patients with or without symptoms of chronic rhinitis. All patients had an indication for tonsillectomy prior to their inclusion in this study. Samples were obtained under general anesthesia at the time of programmed surgery and fixed in a paraformaldehyde-picric acid mixture. Cryostat sections were immunostained for the following neuronal markers: protein-gene product 9.5 (PGP), calcitonin gene- related peptide (CGRP), substance P (SP), and C-terminal peptide of neuropeptide Y (CPON). The following classes of vessels were identified: arteries, sinusoids, veins, and arteriovenous anastomoses (AVAs). As shown by immunostaining with the general neuronal marker PGP, each vessel type had a characteristic innervation pattern, differing in the amount of fibers and their distribution within the adventitial and muscle layers. Evaluation of PGP, CPON, and CGRP immunoreactivity patterns indicated that rhinitic arteries and AVAs displayed a richer innervation than did nonrhinitic blood vessels. Quantification of vascular PGP immunostaining confirmed the difference of vascular innervation between nonrhinitic and rhinitic patients. Fibers immunostained by CPON partially accounted for the rhinitic arterial hyperinnervation.
Assuntos
Mucosa Nasal/irrigação sanguínea , Fibras Nervosas/patologia , Rinite/patologia , Conchas Nasais/irrigação sanguínea , Artérias/inervação , Anastomose Arteriovenosa/inervação , Vasos Sanguíneos/química , Vasos Sanguíneos/inervação , Peptídeo Relacionado com Gene de Calcitonina/análise , Criança , Pré-Escolar , Doença Crônica , Humanos , Imuno-Histoquímica , Proteínas do Tecido Nervoso/análise , Neuropeptídeo Y/análise , Fragmentos de Peptídeos/análise , Substância P/análise , Tioléster Hidrolases/análise , Ubiquitina TiolesteraseRESUMO
Sections of the rat testis and whole-mounts of the testicular capsule were studied microscopically using the glyoxylic acid-induced fluorescence method, to detect monoamines, and immunohistochemical procedures for the detection of immunoreactivities to protein gene-product 9.5 (PGP 9.5), the C-terminal accompanying peptide of neuropeptide Y (CPON), and vasoactive intestinal polypeptide (VIP). Monoaminergic nerves were only observed around the intracapsular blood vessels: the initial segment of the testicular artery and the superior venous plexus, and in the anterior aspect of the upper and lower testicular poles. These capsular nerve networks were associated with the superior and inferior ligaments of the testis. Nerves displaying PGP 9.5 and CPON immunoreactivity appeared in the same sites and followed the same distribution as monoaminergic nerves. By contrast, VIP-immunoreactive fibers were only found in the nerve network of the lower pole. Observations done after different surgical denervation procedures demonstrated that the superior spermatic nerve was the source of fibers for testicular vessels and for the nerve network of the upper pole. On the other hand, fibers from the inferior spermatic nerve were restricted to the nerve network of the lower pole.
Assuntos
Neuropeptídeo Y/análise , Fragmentos de Peptídeos/análise , Testículo/inervação , Tioléster Hidrolases/análise , Peptídeo Intestinal Vasoativo/análise , Animais , Artérias/anatomia & histologia , Artérias/inervação , Imuno-Histoquímica , Masculino , Fibras Nervosas/química , Ratos , Ratos Sprague-Dawley , Testículo/irrigação sanguínea , Ubiquitina Tiolesterase , Veias/anatomia & histologia , Veias/inervaçãoRESUMO
We undertook a light and scanning electron microscopic study of the eye in the Magellanic penguin (Spheniscus magellanicus). The anatomical peculiarities of the eyeball shape in Sphenisciformes have been previously described by others; here, we show that they are accompanied by several modifications in the organization of the anterior segment of the eye. The main change was found in the portion of opaque sclera extending from the cornea to the anterior border of the scleral ossicles, which was much broader than in other avian eyes. This scleral region was made of a very dense fibrous tissue and was as difficult to cut as the ossicles. The corneo-scleral boundary was also different from that of other birds, since the aqueous humor channel and the pectinate ligament were located 1.0-1.5 mm posterior to the cornea. The osseous ring was formed by 13 bones, including three pairs of over- and underplates. There was a single ciliary muscle, with meridionally oriented striated fibers. They were inserted on a circumference along the boundary between the fibrous sclera and the ossicles, far away from the wall of the aqueous humor channel. On their posterior end, the muscle fibers formed a tendinous structure attached to the inner surface of the sclera and to the outer surface of the ciliary body. Only short zonular fibrils were observed. These anatomical features are probably relevant for the adaptation of penguin eyes to vision on land and in the aquatic environment.