RESUMO
The aim of this study was to quantify the lengths of nerve segments within the brachial plexus. Twenty cadavers were dissected bilaterally, giving a total of 40 brachial plexuses for measurement. Individual lengths of plexus segments were measured and recorded, and means and standard deviations were calculated for all data. Differences between the means were statistically evaluated using the Student's t-test. Only 3 of 16 segments were found to be longer in women on average, which included the anterior division of the superior trunk, the anterior division of the middle trunk and the posterior division of the inferior trunk. All three cords (medial, lateral, and posterior) were found to be significantly different between genders, the longer segments being in males. Significant bilateral differences were also observed when right and left brachial plexuses from each cadaver were compared. Extra lateral heads (ELHs) to the median nerve were found in 50% of brachial plexuses, the anatomy of which varied bilaterally as well as between genders. Awareness of this variability is important both to anatomists and to clinicians who operate on and around the brachial plexus.
Assuntos
Plexo Braquial/anatomia & histologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de ReferênciaRESUMO
A correlative radioimmunological-biochemical-ultrastructural study of the rat pineal gland was undertaken during the summer months when pineal arginine vasotocin (AVT) immunoactivity increases up to 200-fold. RIA confirmed a rapid rise in AVT activity during mid-August regardless of the time of day sampled. Pineal indoles were separated by HPLC and measured using electrochemical detection. Serotonin (5-HT) and 5-hydroxyindoleacetic acid levels were consistently elevated in daytime samples, and there was a significant trend for increased day and nighttime levels of 5-HT from July to September. Mid-dark levels of melatonin also exhibited a significant increase over the sample period. Nighttime levels of N-acetylserotonin mirrored fluctuations in 5-HT in the preceding photoperiod. Ultrastructural components implicated in peptide/protein and/or indole biosynthesis were quantified by stereological morphometry. The greatest amounts of rough endoplasmic reticulum stacks, lipid droplets, and annulate lamellae-like bodies coincided with peak AVT activity. Dense-cored vesicles and synaptic ribbons were consistently more frequent during the dark period. The number of dense-cored vesicles and nucleolar size tended to be greatest before and after the peak in AVT immunoactivity. These observations are consistent with the hypotheses that endoplasmic reticulum and lipid are functionally related to the synthesis and/or storage of peptide/protein factors and that numerical changes in synaptic ribbons and dense-cored vesicles are more closely related to day/night differences in indole metabolism.
Assuntos
Indóis/análise , Glândula Pineal/ultraestrutura , Estações do Ano , Vasotocina/análise , 5-Hidroxitriptofano/análise , Animais , Cromatografia Líquida de Alta Pressão , Ácido Hidroxi-Indolacético/análise , Hidroxitriptofol/análise , Masculino , Microscopia Eletrônica , Glândula Pineal/análise , Radioimunoensaio , Ratos , Ratos Endogâmicos , Serotonina/análise , Triptofano/análogos & derivados , Triptofano/análiseRESUMO
The pineal of the burrow-inhabiting, blind goby, Typhlogobius californiensis, was studied by light and electron microscopy. The two predominant cell types were photoreceptor and supportive cells. Ganglion cells could not be positively identified. The majority of photoreceptor cells had well developed outer segments and made apparent synaptic contact with nerve processes of unknown origin. Similar unmyelinated nerve fibers containing dense-cored vesicles were seen descending the pineal stalk. The cytoplasm of supportive cells contained several Golgi zones, occasional dense aggregations of smooth endoplasmic reticulum, abundant quantities of glycogen, some dense-cored vesicles and unusual rod crystalline inclusions measuring approximately 0.5 micrometer in width and 4-5 micrometer in length. These observations suggest that the pineal in this light-deprived species has retained its photoreceptive function and is a metabolically active organ which may also function in secretion.
Assuntos
Peixes/anatomia & histologia , Glândula Pineal/anatomia & histologia , Animais , Epitélio/anatomia & histologia , Junções Intercelulares/ultraestrutura , Células Fotorreceptoras/anatomia & histologiaRESUMO
Evidence in support of melatonin's role as an immunomodulator is incomplete and, in some cases, contradictory. The present studies determined whether melatonin modulates the activity of stimulated macrophages. In vitro lipopolysaccharide (LPS, 10-1000 ng/ml) treatment of alveolar, splenic and peritoneal macrophages isolated from mice and/or rats resulted in a dose-dependent increase in interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF-alpha) secretion. Treatment with melatonin (10(-10)-10(-6) M) prior to the addition of LPS, had no effect on IL-1beta or TNF-alpha release. Additionally, melatonin had no effect on stimulated BV2 microglial cell line cytokine secretion. To determine whether melatonin had an indirect effect on macrophage cytokine release via T cells, melatonin was added to unfractionated mouse spleen cells. Again, melatonin showed no priming effect on LPS-stimulated spleen cells. These results suggest that melatonin has no direct or indirect effect on mouse and rat macrophages. In vivo studies, where melatonin was continuously available in the drinking water, showed that melatonin did not have a priming effect on LPS-stimulated mouse peritoneal macrophages. These findings suggest that melatonin is not an important modulator of macrophage and microglia function.
Assuntos
Adjuvantes Imunológicos/farmacologia , Citocinas/metabolismo , Macrófagos/efeitos dos fármacos , Melatonina/farmacologia , Microglia/efeitos dos fármacos , Neuroimunomodulação/efeitos dos fármacos , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Células Cultivadas/efeitos dos fármacos , Células Cultivadas/imunologia , Células Cultivadas/metabolismo , Citocinas/imunologia , Relação Dose-Resposta a Droga , Interleucina-1/imunologia , Interleucina-1/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Monócitos/citologia , Monócitos/efeitos dos fármacos , Monócitos/imunologia , Neuroimunomodulação/fisiologia , Nitritos/metabolismo , Ratos , Ratos Sprague-Dawley , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The circumventricular organs (CVOs) in the brain are without a blood-brain barrier (BBB) and as such directly exposed to blood plasma constituents and blood-borne pathogens. In light of previous studies showing discrepancies regarding the immunocompetence of these organs, we initiated the present study to provide a comprehensive immunohistochemical analysis of the cellular expression of immune-associated antigens within the pineal gland, area postrema and the subfornical organ. In all CVOs, subpopulations of cells morphologically similar to complement receptor type 3 immunoreactive microglial/macrophage cells expressed major histocompatibility complex (MHC) class II antigen, leucocyte common antigen (LCA/CD45), as well as CD4 and ED1 antigen. Based on morphological criteria the MHC class II antigen expressing cells could be grouped into a major population of classical parenchymal and perivascular ramified microglial cells and a minor population presenting itself as scattered or small groups of rounded macrophage-like cells. CD4 and ED1 antigen were expressed by both cell types. CD45 was preferentially expressed by macrophage-like cells. MHC class I antigen was expressed by the vascular endothelium in both BBB-protected and BBB-deficient areas and was additionally present as a lattice-like network throughout the BBB-deficient parenchyma in all CVOs. The results suggest that the BBB-free areas of the brain besides being constantly surveyed by blood-borne macrophages, possess an intrinsic immune surveillance system based on resting and activated microglial cells, which may function as a non-endothelial, cellular barrier against blood-borne pathogens.
Assuntos
Barreira Hematoencefálica , Encéfalo/imunologia , Antígenos de Histocompatibilidade Classe II/análise , Antígenos de Histocompatibilidade Classe I/análise , Animais , Antígenos CD11/análise , Antígenos CD4/análise , Imunoglobulina G/análise , Imuno-Histoquímica , Antígenos Comuns de Leucócito/análise , Masculino , Microglia/química , Ratos , Ratos Endogâmicos WKYRESUMO
Lewis rats immunized with Peptide M (an oligopeptide epitope of the S-antigen protein) developed experimental autoimmune uveoretinitis (EAU) and experimental autoimmune pinealitis (EAP). Temporal changes in mononuclear infiltrate to the pineal gland were quantitated by computer image analysis of sections immunostained with monoclonal antibodies to specific mononuclear populations. T helper/inducer cells (W3/25+) and monocyte/macrophages (OX-42+) were elevated during the early phases of inflammation (day 15) while cytotoxic/suppressor T cells (OX-8+) were elevated at days 15 and 21. Expression of MHC class II (OX-6) was markedly enhanced on pineal glia, but was not present on vascular endothelia during EAP. Ultrastructurally, many capillaries exhibited thickenings of the endothelia and basal lamina. EAP had little effect on the fine structure of pinealocytes and glia and there was little evidence of cellular destruction by day 21, in contrast to the extensive retinal destruction resulting from EAU. These findings suggest fundamental differences between EAU and EAP related to mechanisms of antigen processing/recognition in autoimmune diseases. Our study further indicates the importance of EAP as a model to investigate neuroendocrine-immune interactions.
Assuntos
Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Antígenos de Histocompatibilidade Classe II/biossíntese , Leucócitos Mononucleares/imunologia , Glândula Pineal/imunologia , Glândula Pineal/ultraestrutura , Animais , Proteínas do Olho/imunologia , Imuno-Histoquímica , Inflamação/imunologia , Inflamação/patologia , Masculino , Fragmentos de Peptídeos/imunologia , Glândula Pineal/patologia , Ratos , Ratos Endogâmicos Lew , Retinite/imunologia , Linfócitos T Auxiliares-Indutores , Linfócitos T ReguladoresRESUMO
We have evaluated the accumulation of neutrophils in the gut and their infiltration into the intestinal extravascular spaces in rats subjected to a 25% total body surface area scald burn. The accumulation of neutrophils was assessed via measurements of myeloperoxidase (MPO) activity in the intestinal homogenates, and the immunohistochemical localization of neutrophil NADPH oxidase component proteins (p47phox and p67phox) within the intestinal extravascular spaces determined neutrophil tissue infiltration. MPO measurements demonstrated a 12- and 21-fold increase above the control value in the intestinal tissue at day 1 and day 3 post-burn, respectively, suggesting that a substantial total tissue accumulation of neutrophils occurs in the gut after burn injury. The immunohistochemical staining procedures showed both a definitive presence of the neutrophil in the intestinal extravascular spaces and an enhanced immunoreactivity in neutrophils accumulating in intestine after burn injury. There was no evidence of either the presence of neutrophils in the extravascular regions or any significant neutrophil immunoreactivity to NADPH oxidase component proteins in the intestines of sham control rats. These findings indicate that burn injury causes an enhanced migration of circulating neutrophils into the intestinal interstitial spaces and an upregulation of NADPH oxidase activity in the infiltrating neutrophils.
Assuntos
Queimaduras/enzimologia , Íleo/enzimologia , Jejuno/enzimologia , NADPH Oxidases/biossíntese , Neutrófilos/enzimologia , Animais , Queimaduras/imunologia , Queimaduras/patologia , Quimiotaxia de Leucócito , Indução Enzimática , Íleo/imunologia , Íleo/patologia , Mucosa Intestinal/enzimologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/patologia , Jejuno/imunologia , Jejuno/patologia , Masculino , NADPH Oxidases/genética , Estresse Oxidativo , Peroxidase/análise , Fosfoproteínas/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
The pineal gland is part of the neuroendocrine system that modulates immune functions. Because the gland is outside the blood-brain barrier, it is accessible to direct feedback from circulating cytokines that affect the synthesis and secretion of melatonin. Recent studies have suggested that intrinsic immunoregulatory cytokines mediate these neuro-immune interactions under the control of sympathetic innervation to the pineal. This study focused on the expression of transforming growth factor-beta1 (TGF-beta1) and interleukin-6 (IL-6), two cytokines that have important regulatory functions on both neurons and immune cells. Northern blot RNA analysis showed that TGF-beta1, but not IL-6, was expressed in freshly dissected rat pineal glands from neonatal age (1-day-old) into adults. Immunocytochemistry for TGF-beta1 in adult glands revealed localization of this protein in astrocyte-like cells. The sympathetic neurotransmitter norepinephrine (NE) increased transcript levels for both TGF-beta1 and IL-6 in adult pineal organ cultures. The effect of NE on IL-6 expression was not found in dispersed cell cultures established from neonatal pineal glands. The immunoregulatory molecule interleukin-1beta (IL-1beta) up-regulated the expression of both IL-6 and TGF-beta1 in adult pineal organ cultures, but not in neonate pineal organ cultures. These findings suggest that TGF-beta1 and IL-6 have intrinsic regulatory roles in the pineal gland and that both neural and immune factors are important mechanisms of regulation.
Assuntos
Agonistas alfa-Adrenérgicos/farmacologia , Interleucina-1/farmacologia , Interleucina-6/biossíntese , Norepinefrina/farmacologia , Glândula Pineal/metabolismo , Fator de Crescimento Transformador beta/biossíntese , Animais , Células Cultivadas , Imuno-Histoquímica , Microscopia Confocal , Técnicas de Cultura de Órgãos , Sistema Nervoso Parassimpático/fisiologia , Glândula Pineal/efeitos dos fármacos , RNA Mensageiro/biossíntese , Ratos , Ratos Sprague-Dawley , Fator de Crescimento Transformador beta1RESUMO
Fetal neocortical block transplants were implanted into the excitotoxically ablated sensorimotor cortex of adult rats in order to examine the density of innervation and distribution of presumptive host derived afferent fibers within these transplants. Cholinergic fiber innervation was examined at 3 months post grafting by measuring acetylcholinesterase (AChE) and choline acetyl-transferase (ChAT) enzyme activities within the grafts and within the corresponding host cortex by radiochemical enzyme assays as well as by AChE histochemistry for the visualization of AChE positive fibers. Noradrenergic and serotonergic inputs were examined by high performance liquid chromatography (HPLC) measurements of noradrenaline (NA) and serotonin (5-hydroxytryp-tamine, 5-HT) concentrations as well as by tyrosine hydroxylase (TH) and 5-HT immunocytochemistry for the visualization of monoaminergic fiber distribution. Our results demonstrated that the grafts contained significantly lower levels of neurotransmitter markers when compared to normal unablated cortex. The anatomical analysis showed an unequal fiber distribution within the transplants. Areas adjacent to the host tissue revealed a relatively dense fiber innervation when compared to the density observed within the more central parts of the transplants, and the anatomical data therefore supported the biochemical data in suggesting an overall lower cholinergic and monoaminergic innervation of fetal neocortical transplants placed into the lesioned adult cortex when compared to normal cortex.
RESUMO
A comparative study of pinealocyte synaptic ribbons (SR) revealed two predominant populations exhibiting either a rod/ribbon shape (SRr) or a spherical/punctate shape (SRsp). Species-specific differences were found in the abundance of SR, the ratio of SRr/SRsp, and the occurrence of SR in ribbon fields. The close topographical relationship of SR to the plasma membrane and the numerical changes that occurred with changes in metabolism of the pinealocytes suggest that SR have important vesicle-mediated interactions with the cell membrane. Experiments designed to clarify the relationship between SR and pineal neuroendocrine function revealed a positive correlation between SR numbers and indole intermediates during pineal development in the rat, and increased SR frequency after denervation of the rat pineal gland or administration of the beta-adrenergic agonist, isoproterenol. These data are consistent with the hypothesis that SR function is linked to receptor mechanisms regulating indoleamine production in the pineal gland.
Assuntos
Sistemas Neurossecretores/fisiologia , Glândula Pineal/ultraestrutura , Transdução de Sinais/fisiologia , Vesículas Sinápticas/ultraestrutura , Animais , Comunicação Celular/fisiologia , Endocitose/fisiologia , Melatonina/biossíntese , Glândula Pineal/fisiologia , Especificidade da Espécie , Vesículas Sinápticas/fisiologiaRESUMO
Fetal neocortical transplants placed into frontal cortex aspiration lesion cavities in newborn rats have been shown to survive and exchange connections with the host brain. To further study the afferent innervation of such transplants, enzyme- and immunohistochemical techniques were employed to examine the distribution of cholinergic, catecholaminergic and serotonergic fibers within the transplants, and radiochemical enzyme assays and high performance liquid chromatography were used to determine the content of neurotransmitter markers for these same fiber systems. To examine functional integration of the transplanted neurons in terms of activation of molecular signaling systems, the graft recipient animals were exposed to a novel open field environment. This behavioral testing paradigm is known to induce c-fos mRNA and Fos protein within several areas of the normal brain, including the sensorimotor cortex. Subsequent detection of the induction of this particular immediate early gene (transcription as well as translation) in the grafts would gene (transcription as well as translation) in the grafts would accordingly indicate genomic activation and therefore functional integration at the level of molecular signaling systems. Our results showed that these global fiber systems are distributed evenly throughout the extent of three mo old neocortical grafts and that the content of transmitter-related markers for these systems do not differ significantly from control cortex. Open field exposure of the grafted animals resulted in c-fos mRNA and Fos protein expression of cells distributed throughout the transplants. We conclude that the "global" fiber system innervation of neocortical transplants placed into newborn rats is similar to the innervation of normal cortex and that grafted neurons respond to host brain activation at the level of molecular signaling systems.
Assuntos
Transplante de Tecido Encefálico , Encéfalo/metabolismo , Transplante de Tecido Fetal , Animais , Animais Recém-Nascidos , Comportamento Animal , Encéfalo/embriologia , Sobrevivência de Enxerto , Proteínas Proto-Oncogênicas c-fos/biossíntese , RNA Mensageiro/análise , RatosRESUMO
Pineal supportive cells in a teleost were shown to contain the glial fibrillary acidic (GFA) and S-100 proteins by electron microscopic immunocytochemistry. Both proteins are known to exhibit a high degree of evolutionary conservation. The pineal photoreceptor cells did not stain for these marker proteins. A relationship between supportive cells and macroglial elements is therefore implied.
Assuntos
Proteínas de Filamentos Intermediários/metabolismo , Glândula Pineal/anatomia & histologia , Proteínas S100/metabolismo , Animais , Proteína Glial Fibrilar Ácida , Carpa Dourada , Técnicas Imunoenzimáticas , Microscopia Eletrônica , Neuroglia/ultraestrutura , Glândula Pineal/metabolismoRESUMO
Nerve growth factor receptor immunoreactivity (NGFRI) in the pineal gland was examined both light and electron microscopically using the monoclonal antibody 192IgG. NGFRI was located on sympathetic fibers and on perivascular cells resembling macrophage/microglia. A pineal gland dispersed cell culture model confirmed the presence of NGFRI in cells that exhibited processes of varying lengths and were distributed among pinealocytes and other flat cells. Pinealocytes in dispersed cell culture were identified immunocytochemically by their expression of S-antigen, their round shape and small size and their tendency to extend neurites in the direction of the flat cells in culture. The length of pinealocyte neurites showed a significant increase when cultured in the presence of NGF (25 ng/ml), suggesting that trophic factors, mediated by these macrophage/microglial cells, are important to the morphogenesis of these neuroendocrine cells. Neurotrophic activation of these neuroendocrine macrophage/microglia may have neuro-immunomodulatory implications leading to expression of proteins encoded by the major histocompatibility complex.
Assuntos
Fatores de Crescimento Neural/farmacologia , Neuritos/efeitos dos fármacos , Glândula Pineal/química , Receptores de Fator de Crescimento Neural/análise , Animais , Anticorpos Monoclonais , Antígenos/análise , Células Cultivadas , Gânglios Simpáticos/fisiologia , Técnicas Imunoenzimáticas , Imunoglobulina G , Microscopia Eletrônica , Glândula Pineal/citologia , Glândula Pineal/ultraestrutura , Ratos , Ratos Sprague-DawleyRESUMO
This study investigated the effects of MRI on receptor-mediated activation of pineal gland indole biosynthesis. Exposure of rats to MRI reduced the effects of isoproterenol on pineal serotonin and N-acetylserotonin levels suggesting that strong magnetic fields and/or radio-frequency pulsing used in MRI inhibited beta-adrenergic activation of the gland. There was no effect of MRI on saline controls.
Assuntos
Campos Eletromagnéticos , Fenômenos Eletromagnéticos , Imageamento por Ressonância Magnética , Glândula Pineal/fisiologia , Receptores Adrenérgicos beta/fisiologia , Serotonina/metabolismo , Animais , Isoproterenol/farmacologia , Masculino , Glândula Pineal/metabolismo , Ratos , Ratos Endogâmicos , Receptores Adrenérgicos beta/efeitos dos fármacosRESUMO
Pinealocyte synaptic ribbons (SR) in the 13-lined ground squirrel were quantified at monthly intervals over a one-year period spanning the hibernating and reproductive cycles of these animals. SR numbers were high (70-90/20,000 microns2) during periods of activity and reproductive quiescence (May-October). With the onset of hibernation (November-December) there was a rapid 6 to 7-fold reduction in SR frequency. During arousal (January-February) and sexual maturation (March-April) there was a gradual increase in SR frequency. The winter decline in SR frequency is consistent with the decline in pineal melatonin during hibernation and supports the hypothesis that pinealocyte SR play an important role in the neurotransduction of melatonin biosynthesis.
Assuntos
Hibernação/fisiologia , Organelas/ultraestrutura , Glândula Pineal/ultraestrutura , Reprodução/fisiologia , Sciuridae/anatomia & histologia , Animais , Feminino , Masculino , Melatonina/sangue , Melatonina/metabolismo , Glândula Pineal/citologia , Glândula Pineal/metabolismo , Sciuridae/metabolismo , Sciuridae/fisiologia , Estações do AnoRESUMO
Acid phosphatase (ACP) activity was investigated in the photoreceptive pineal gland of the goldfish by both light and electron microscopy. Intraluminal macrophages exhibited the greatest ACP reactivity that was generally confined to lysosomal bodies containing membranous debris. Quantitative light microscopic evaluation revealed significantly higher ACP reactivity in animals collected at mid-light compared to those collected at mid-dark suggesting that functional activities of macrophages in this photoneuroendocrine organ are cyclical over the 24-h photoperiod. Day-night differences in macrophage ACP activity may reflect rhythmic renewal and shedding of photoreceptor outer segment membranes.
Assuntos
Fosfatase Ácida/metabolismo , Ritmo Circadiano , Macrófagos/enzimologia , Glândula Pineal/enzimologia , Animais , Carpa Dourada , Histocitoquímica , Macrófagos/fisiologia , Macrófagos/ultraestrutura , Microscopia Eletrônica , Glândula Pineal/fisiologia , Glândula Pineal/ultraestruturaRESUMO
PURPOSE: To demonstrate the applicability of server statistics, in combination with user surveys, to evaluate utilization of Web-based computer-aided instruction (CAI) in the undergraduate medical curriculum. METHOD: Individual user surveys with students' names provided information about computer literacy prior to the course and use of CAI during the course. Utilization of specific web-based CAI developed for the course was recorded by server software and the daily logs correlated with course content. Regression analyses were used to measure correlation of server access logs of individual students versus information from user surveys and performances in the course based on in-course examinations. RESULTS: There was no correlation between computer literacy of students at matriculation and their subsequent levels of use of CAI in the curriculum. Utilization of CAI developed for specific course objectives coincided closely with course content, which is an indication of the effectiveness of the applications in achieving their curricular objectives. In contrast, student use of tutorials coincided most closely with in-course examinations. Students' responses to surveys were generally substantiated by server statistics, but discrepancies were sufficiently large (10% to 20%) to call into question the validity of these surveys. Significant differences in CAI utilization correlated with the performances of students in the course. CONCLUSIONS: This study demonstrates an important advantage of web-based applications to collect and evaluate CAI utilization efficiently and objectively at both the level of the class and the level of the individual student.
Assuntos
Instrução por Computador , Educação de Graduação em Medicina , Internet , Ciência/educação , Alfabetização Digital , Instrução por Computador/estatística & dados numéricos , Currículo , Avaliação Educacional , Humanos , Avaliação de Programas e Projetos de Saúde , Análise de Regressão , Reprodutibilidade dos Testes , Software , Interface Usuário-ComputadorRESUMO
The teleost pineal organ contains functional photoreceptors that synapse with pinealofugal neurons. This study examined the effects of environmental lighting on protein content and levels of putative amino acid transmitters, as well as structural components associated with protein synthesis and neurotransmission. Goldfish subjected to continual illumination for 3 days tended to have increased pineal levels of free amino acids and protein compared to dark adapted glands. Similar responses to environmental lighting occurred in cultured glands suggesting a functional relationship to photosensory mechanisms. Morphometric ultrastructural analyses of pineal photoreceptors showed an increased size of nucleoli (especially the fibrillar component), Golgi bodies, and synaptic ribbons when glands were subjected to continuous light both in vivo and in vitro. The good agreement between protein levels and nucleolar morphology indicates a general effect of environmental lighting on photoreceptor protein metabolism, which may be related to photoreceptor outer segment renewal. Parallel changes in levels of certain amino acids (e.g., glutamate) and size of synaptic ribbons is consistent with an hypothesized role of amino acids in photoreceptor neurotransmission.
Assuntos
Cyprinidae , Adaptação à Escuridão , Carpa Dourada , Luz , Células Fotorreceptoras/efeitos da radiação , Glândula Pineal/efeitos da radiação , Aminoácidos/metabolismo , Animais , Nucléolo Celular/ultraestrutura , Cyprinidae/anatomia & histologia , Cyprinidae/fisiologia , Retículo Endoplasmático/ultraestrutura , Carpa Dourada/anatomia & histologia , Carpa Dourada/fisiologia , Complexo de Golgi/ultraestrutura , Mitocôndrias/ultraestrutura , Proteínas do Tecido Nervoso/metabolismo , Técnicas de Cultura de Órgãos , Células Fotorreceptoras/metabolismo , Células Fotorreceptoras/ultraestrutura , Glândula Pineal/metabolismo , Glândula Pineal/ultraestrutura , Sinapses/ultraestrutura , Transmissão SinápticaRESUMO
Profiles of pineal indolealkylamines were estimated by high performance liquid chromatography and were correlated in individual glands of male rats sacrificed over several light:dark cycles and after acute exposure to light at night. A significant and positive correlation of 5HIAA vs 5HT in individual glands over both normal and experimental lighting conditions suggested that oxidative deamination is not a major factor in photic regulation of pineal 5HT levels and that the formation of 5HIAA is dependent on substrate availability. Regression analysis of other indole constituents revealed that there was a positive and significant correlation between 5HT vs N-acetylserotonin, but not between 5HT vs melatonin and N-acetylserotonin vs melatonin in individual glands during the dark phase of a light:dark cycle. We propose that this effect may be related to a pulsatile release of melatonin into the blood stream and is the result of sampling glands at different stages in the storage/release of melatonin.
Assuntos
Ritmo Circadiano , Luz , Glândula Pineal/metabolismo , Serotonina/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Ácido Hidroxi-Indolacético/biossíntese , Masculino , Melatonina/biossíntese , Melatonina/metabolismo , Glândula Pineal/efeitos da radiação , Ratos , Ratos Endogâmicos , Serotonina/análogos & derivados , Serotonina/biossínteseRESUMO
Neurohypophyseal peptide hormone activity is present in the pineal gland of mammals, and varies over a seasonal cycle. Pineal peptide levels, measured by arginine vasotocin (AVT) radioimmunoassay, increase dramatically for a brief time during August each year. The manner in which this cycle is regulated is as yet unknown. Input to the pineal from sympathetic axons arising in the superior cervical ganglia (SCG) is essential for the generation and regulation of the circadian rhythm in melatonin synthesis, and is the only pathway known to regulate pineal biochemical processes. It was of interest then to determine the impact of the SCG on the seasonal peptide cycle. Levels of pineal arginine vasotocin immunoactivity (iAVT) were monitored during August, 1984, in rats which had been superior cervical ganglionectomized (SCGX), in sham-operated and intact controls (L:D 12:12), and in rats subjected to L:D 22:2. The results indicate that SCGX does not abolish the seasonal cycle, but may influence the timing of the iAVT peak. Inhibition of pineal melatonin synthesis by exposure of rats to L:D 22:2 did not mimic the phase delay seen with SCGX, but did cause a significant increase in the amplitude of the August iAVT activity peak.