Extracellular adenosine 5'-triphosphate concentrations changes in rat spinal cord associated with the activation of urinary bladder afferents. A microdialysis study. / Variação da concentração extracelular de 5'-trifosfato de adenosina na medula espinal de rata associadas a fibras aferentes vesicais. Um estudo com microdiálise

ABSTRACT Objective To determine adenosine 5’-triphosphate levels in the interstice of spinal cord L6-S1 segment, under basal conditions or during mechanical and chemical activation of urinary bladder afferents. Methods A microdialysis probe was transversally implanted in the dorsal half of spinal cord L6-S1 segment in female rats. Microdialysate was collected at 15 minutes intervals during 135 minutes, in anesthetized animals. Adenosine 5’-triphosphate concentrations were determined with a bioluminescent assay. In one group of animals (n=7) microdialysate samples were obtained with an empty bladder during a 10-minutes bladder distension to 20 or 40cmH2O with either saline, saline with acetic acid or saline with capsaicin. In another group of animals (n=6) bladder distention was performed and the microdialysis solution contained the ectonucleotidase inhibitor ARL 67156. Results Basal extracellular adenosine triphosphate levels were 110.9±35.34fmol/15 minutes, (mean±SEM, n=13), and bladder distention was associated with a significant increase in adenosine 5’-triphosphate levels which was not observed after bladder distention with saline solution containing capsaicin (10µM). Microdialysis with solution containing ARL 67156 (1mM) was associated with significantly higher extracellular adenosine 5’-triphosphate levels and no further increase in adenosine 5’-triphosphate was observed during bladder distension. Conclusion Adenosine 5’-triphosphate was present in the interstice of L6-S1 spinal cord segments, was degraded by ectonucleotidase, and its concentration increased following the activation of bladder mechanosensitive but not of the chemosensitive afferents fibers. Adenosine 5’-triphosphate may originate either from the central endings of bladder mechanosensitive primary afferent neurons, or most likely from intrinsic spinal neurons, or glial cells and its release appears to be modulated by capsaicin activated bladder primary afferent or by adenosine 5’-triphosphate itself.

RESUMO Objetivo Determinar as concentrações extracelulares do 5’-trifosfato de adenosina no interstício dos segmentos medulares L6-S1, em condições basais ou durante a ativação mecânica e química das fibras aferentes vesicais. Métodos Um cateter de microdiálise foi implantado no sentido transversal na parte dorsal da medula espinal, entre os segmentos L6-S1 de ratas. O microdialisado foi coletado em intervalos de 15 minutos, durante 135 minutos, com os animais anestesiados. A concentração de 5’-trifosfato de adenosina nas amostras foi determinada mediante ensaio de bioluminescência. Em um grupo de animais (n=7), as amostras de microdialisado foram obtidas com a bexiga vazia, com distensão da bexiga para volume de 20 ou 40cmH2O, com solução salina, solução salina com ácido acético, ou solução salina com capsaicina. Em outro grupo (n=6), foi realizada com a bexiga distendida, e a solução para microdiálise continha o inibidor de ectonucleotidase ARL 67156. Resultados Os níveis extracelulares de trifosfato de adenosina no início do estudo foram 110,9±35,36fmol/15 minutos (média±EPM, n=13), e a distensão da bexiga causou um aumento nos níveis de 5’-trifosfato de adenosina, o que não foi observado após a distensão da bexiga com solução salina contendo capsaicina (10µM). A microdiálise com solução contendo ARL 67156 (1mM) foi associada com significante aumento dos níveis de trifosfato de adenosina extracelular, e nenhum aumento do trifosfato de adenosina foi observado durante a distensão da bexiga. Conclusão O 5’-trifosfato de adenosina está presente no interstício do segmento L6-S1 da medula espinal, é degradado por ectonucleotidases, e sua concentração aumentou com a ativação das fibras aferentes mecanossensíveis da bexiga, mas não das quimiossensíveis. O 5’-trifosfato de adenosina pode ter sido liberado das terminações centrais dos neurônios aferentes primários mecanossensíveis ou, mais provavelmente, de neurônios espinais intrínsecos, ou ainda de células gliais. Sua liberação parece ser modulada por fibras aferentes primárias da bexiga ativadas pela capsaicina ou pelo próprio 5’-trifosfato de adenosina.

Comparison of arylalkylamine N-acetyltransferase and melatonin receptor type 1B immunoreactivity between young adult and aged canine spinal cord

Melatonin affects diverse physiological functions through its receptor and plays an important role in the central nervous system. In the present study, we compared immunoreactivity patterns of arylalkylamine N-acetyltransferase (AANAT), an enzyme essential for melatonin synthesis, and melatonin receptor type 1B (MT2) in the spinal cord of young adult (2~3 years) and aged (10~12 years) beagle dogs using immunohistochemistry and Western blotting. AANAT-specific immunoreactivity was observed in the nuclei of spinal neurons, and was significantly increased in aged dog spinal neurons compared to young adult spinal neurons. MT2-specific immunoreactivity was found in the cytoplasm of spinal neurons, and was predominantly increased in the margin of the neuron cytoplasm in aged spinal cord compared to that in the young adult dogs. These increased levels of AANAT and MT2 immunoreactivity in aged spinal cord might be a feature of normal aging and associated with a feedback mechanism that compensates for decreased production of melatonin during aging.

Distribución de calbindina y parvoalbúmina y efecto del virus de la rabia sobre su expresión en la médula espinal de ratones / Calbindin and parvalbumin distribution in spinal cord of normal and rabies-infected mice

Introducción. Aunque se trata de una enfermedad infecciosa del sistema nervioso, poco se conoce sobre los mecanismos patogénicos de la infección con el virus de la rabia. En particular, son escasos los estudios sobre su histopatología en la médula espinal. Objetivo. Estudiar la distribución de las proteínas calbindina y parvoalbúmina, en la médula espinal de ratones y evaluar el efecto de la infección con el virus de la rabia sobre su expresión. Materiales y métodos. Se inocularon ratones con virus de la rabia, por vía intracerebral o intramuscular, y se extrajo la médula espinal para hacer cortes transversales, los cuales se sometieron a tratamiento inmunohistoquímico con anticuerpos monoclonales para revelar la presencia de las dos proteínas en ratones normales y en animales infectados. Se llevó a cabo el análisis cualitativo y cuantitativo de la inmunorreacción de las dos proteínas. Resultados. Las proteínas calbindina y parvoalbúmina se distribuyeron de manera diferencial en las láminas de Rexed. La infección con el virus de la rabia produjo una disminución en la expresión de calbindina. Por el contrario, la infección provocó un incremento en la expresión de parvoalbúmina. El efecto de la rabia sobre las dos proteínas fue similar al comparar las dos vías de inoculación. Conclusión. El efecto diferencial de la infección con el virus de la rabia sobre calbindina y parvoalbúmina en la médula espinal de ratones, es similar al reportado anteriormente para áreas encefálicas. Esto sugiere uniformidad en su respuesta a la infección en todo el sistema nervioso central y es un aporte importante para el conocimiento de la patogénesis de la rabia.

Introduction: Rabies is a fatal infectious disease of the nervous system; however, the knowledge about the pathogenic neural mechanisms in rabies is scarce. In addition, there are few studies of rabies pathology of the spinal cord. Objective: To study the distribution of calcium binding proteins calbindin and parvalbumin and assessing the effect of rabies virus infection on their expression in the spinal cord of mice. Materiales y methods: Mice were inoculated with rabies virus, by intracerebral or intramuscular route. The spinal cord was extracted to perform some crosscuts which were treated by immunohistochemistry with monoclonal antibodies to reveal the presence of the two proteins in normal and rabies infected mice. We did qualitative and quantitative analyses of the immunoreactivity of the two proteins. Results: Calbindin and parvalbumin showed differential distribution in Rexed laminae. Rabies infection produced a decrease in the expression of calbindin. On the contrary, the infection caused an increased expression of parvalbumin. The effect of rabies infection on the two proteins expression was similar when comparing both routes of inoculation. Conclusion: The differential effect of rabies virus infection on the expression of calbindin and parvalbumin in the spinal cord of mice was similar to that previously reported for brain areas. This result suggests uniformity in the response to rabies infection throughout the central nervous system. This is an important contribution to the understanding of the pathogenesis of rabies.

Effects of systemic administration of ciliary neurotrophic factor on Bax and Bcl-2 proteins in the lumbar spinal cord of neonatal rats after sciatic nerve transection

Ciliary neurotrophic factor (CNTF) is a cytokine that plays a neuroprotective role in relation to axotomized motoneurons. We determined the effect of daily subcutaneous doses of CNTF (1.2 µg/g for 5 days; N = 13) or PBS (N = 13) on the levels of mRNA for Bcl-2 and Bax, as well as the expression and inter-association of Bcl-2 and Bax proteins, and the survival of motoneurons in the spinal cord lumbar enlargement of 2-day-old Wistar rats after sciatic nerve transection. Five days after transection, the effects were evaluated on histological and molecular levels using Nissl staining, immunoprecipitation, Western blot analysis, and reverse transcriptase-polymerase chain reaction. The motoneuron survival ratio, defined as the ratio between the number of motoneurons counted on the lesioned side vs those on the unlesioned side, was calculated. This ratio was 0.77 ± 0.02 for CNTF-treated rats vs 0.53 ± 0.02 for the PBS-treated controls (P < 0.001). Treatment with CNTF modified the level of mRNA, with the expression of Bax RNA decreasing 18 percent (with a consequent decrease in the level of Bax protein), while the expression of Bcl-2 RNA was increased 87 percent, although the level of Bcl-2 protein was unchanged. The amount of Bcl-2/Bax heterodimer increased 91 percent over that found in the PBS-treated controls. These data show, for the first time, that the neuroprotective effect of CNTF on neonatal rat axotomized motoneurons is associated with a reduction in free Bax, due to the inhibition of Bax expression, as well as increased Bcl-2/Bax heterodimerization. Thus, the neuroprotective action of the CNTF on axotomized motoneurons can be related to the inhibition of this apoptotic pathway.

Differential astroglial responses in the spinal cord of rats submitted to a sciatic nerve double crush treated with local injection of cultured Schwann cell suspension or lesioned spinal cord extract: implications on cell therapy for nerve repair

PURPOSE: Reactive astrocytes are implicated in several mechanisms after central or peripheral nervous system lesion, including neuroprotection, neuronal sprouting, neurotransmission and neuropathic pain. Schwann cells (SC), a peripheral glia, also react after nerve lesion favoring wound/repair, fiber outgrowth and neuronal regeneration. We investigated herein whether cell therapy for repair of lesioned sciatic nerve may change the pattern of astroglial activation in the spinal cord ventral or dorsal horn of the rat. METHODS: Injections of a cultured SC suspension or a lesioned spinal cord homogenized extract were made in a reservoir promoted by a contiguous double crush of the rat sciatic nerve. Local injection of phosphate buffered saline (PBS) served as control. One week later, rats were euthanized and spinal cord astrocytes were labeled by immunohistochemistry and quantified by means of quantitative image analysis. RESULTS: In the ipsilateral ventral horn, slight astroglial activations were seen after PBS or SC injections, however, a substantial activation was achieved after cord extract injection in the sciatic nerve reservoir. Moreover, SC suspension and cord extract injections were able to promote astroglial reaction in the spinal cord dorsal horn bilaterally. Conclusion: Spinal cord astrocytes react according to repair processes of axotomized nerve, which may influence the functional outcome. The event should be considered during the neurosurgery strategies.

OBJETIVO: Astrócitos reativos participam de vários mecanismos após lesões do sistema nervoso central e periférico, os quais incluem neuroproteção, brotamento neuronal, neurotransmissão e dor neuropática. As células de Schwann (CS), um tipo de glia periférica, também reagem com a lesão do nervo, podendo interferir com o reparo e cicatrização, crescimento de fibras e regeneração neuronais. Investigamos aqui a possibilidade da terapia celular para o reparo do nervo ciático poder alterar o padrão da ativação astrocitária nos cornos anterior e posterior da medula espinal do rato. MÉTODOS: Suspensão de CS cultivadas ou extrato homogeneizado de medula espinal lesada de rato foram inoculados num reservatório feito a partir de dois esmagamentos aplicados no nervo ciático do rato distantes 0,5mm entre si. Injeção local de salina tamponada serviu como controle. Os ratos foram mortos uma semana após e os astrócitos da medula espinal marcados por método imunohistoquímico e quantificados por análise de imagem. RESULTADOS: No corno anterior da medula, ipsilateral à lesão, ativação astrocitária leve foi vista após as injeções de tampão ou CS, entretanto, ativação celular intensa foi observada nesta região com a inoculação neural do extrato homogeneizado de tecido medular lesado. Adicionalmente, as inoculações de CS e de extrato homogeneizado de tecido medular promoveram forte reação astrocitária no corno dorsal da medula espinal, bilateralmente. CONCLUSÕES: Os astrócitos da medula espinal reagem em função do processo de reparo do nervo lesado, o que pode influenciar o resultado funcional esperado, algo que deve ser considerado durante o planejamento da estratégia neurocirúrgica.

Leukoencephalopathy with brainstem and spinal cord involvement and high brain lactate: report of three brazilian patients

A novel leukoencephalopathy was recently identified based on magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (¹H-MRS) findings. Leukoencephalopathy with brainstem and spinal cord involvement and high lactate (LBSL) is an autosomal recessive disorder characterized by early onset of symptoms and slowly progressive cerebellar, pyramidal and spinal cord dorsal column dysfunction. MRI and ¹H-MRS typically show abnormalities within cerebral and cerebellar white matter, a characteristic involvement of brainstem and spinal cord tracts and elevated lactate in the abnormal white matter. We present three cases with characteristic clinical and neuroimaging findings of this disorder. Some additional unique findings of our patients are discussed, like distal motor neuropathy and elevated creatine kinase in the serum.

Uma nova leucoencefalopatia foi recentemente descrita com base em achados característicos de ressonância magnética e espectroscopia de prótons por ressonância magnética. Leucoencefalopatia com envolvimento do tronco cerebral e da medula espinal e elevação do lactato cerebral é uma doença autossômica recessiva de aparecimento precoce e evolução lenta, caracterizada por disfunção cerebelar, piramidal e das colunas dorsais da medula. Ressonância magnética e espectroscopia de prótons tipicamente demonstram anormalidades na substância branca cerebral e cerebelar, com envolvimento característico de tratos no tronco encefálico e na medula espinhal e aumento de lactato na substância branca cerebral anormal. Relatamos três casos com achados clínicos e de neuroimagem característicos. Achados adicionais peculiares aos nossos pacientes são discutidos, como a elevação da creatina-quinase sérica e a presença de neuropatia motora distal.

The Role of Inducible Nitric Oxide Synthase Following Spinal Cord Injury in Rat

Acute spinal cord injury (SCI) is two-step process that first involves the primary mechanical injury and then the secondary injury is induced by various biochemical reactions. Apoptosis is one of secondary SCI mechanisms and it is thought to play an important role for the delayed neuronal injury. The enhanced formation of nitric oxide (NO) via inducible nitric oxide synthase (iNOS) has been implicated in the pathogenesis of apoptosis in SCI. The level of .iNOS mRNA peaked at 6 hr after SCI and it declined until 72 hr after SCI in a rat model. Double-immunofluorescence staining revealed that iNOS positive cells were stained for ED-1, synaptophysin, GFAP, and oligodendrocyte marker. The terminal deoxynucleotidyl-transferase-mediated dUDP-biotin nick end-labeling (TUNEL) positive cell count was higher for the 72 hr post-SCI group than for the 24 hr post-SCI group. This cell count was also higher going in the caudal direction than in the rostral direction from the epicenter, and especially for the 72 hr group. Treatment with a selective iNOS inhibitor resulted in the reduction of TUNEL-positive cells at the lesion site. These findings suggest that nitric oxide generated by the iNOS of macrophages, neurons, oligodentrocytes, and astrocytes plays an important role for the acute secondary SCI that results from apoptotic cell death.

Melatonin ameliorates autoimmune encephalomyelitis through suppression of intercellular adhesion molecule-1

Melatonin (N-acetyl-5-methoxytryptamine), a pineal neurohormone, is a hydroxyl radical scavenger and antioxidant, and plays an important role in the immune system. We studied the effect of exogenous melatonin on the pathogenesis of experimental autoimmune encephalomyelitis (EAE). EAE was induced in Lewis rats by immunization with rat spinal cord homogenates. Subsequent oral administration of melatonin at 5 mg/kg significantly reduced the clinical severity of EAE paralysis compared with administration of the vehicle alone (p<0.01). Infiltration of ED1 macrophages and CD4 T cells into spinal cords occurred both in the absence and presence of melatonin treatment, but melatonin-treated rats had less spinal cord infiltration of inflammatory cells than did the control group. ICAM-1 immunoreactivity in the blood vessels of EAE lesions was decreased in melatonin-treated rats compared to vehicle-treated rats. These findings suggest that exogenous melatonin ameliorates EAE via a mechanism involving reduced expression of ICAM-1 and lymphocyte function associated antigen-1a in autoimmune target organs.

Studies on the changes of c-fos protein in spinal cord and neurotransmitter in dorsal root ganglion of the rat with an experimental peripheral neuropathy

Animal models for human chronic pain syndromes have been developed and widely used for pain research. One of these neuropathic pain models by Kim and Chung (1992) has many advantages for operation and pain elicitation. In this neuropathic model we have examined the c-fos protein, substance P, CGRP immunoreactivity in dorsal root ganglia and dorsal horn. 50 Sprague-Dawley rats were used for this study. L5 and L6 spinal nerves were ligated tightly to produce the neuropathic pain model. After 2, 4, 8, 16, and 24 hours and 1 week of surgery, rats were anesthetized and sacrificed by perfusion. After confirmation of the roots transected by the surgery, the L5 and L6 dorsal root ganglions and spinal cord were removed and processed for immunohistochemistry. All tissue sections were immunohistochemically stained for substance P, CGRP and c-fos using the peroxidase-antiperoxidase (PAP) method. The number of immunostained substance P and CGRP dorsal root ganglion cells and c-fos immunoreactive dorsal horn cells were counted and analyzed statistically with Mann-Whitney U test. The results are as follows. The number of c-fos protein immunoreactive neurons in the superficial layer of dorsal horn were increased markedly 2 hours after operation, and gradually decreased to normal level 1 week after operation. The number of c-fos protein immunoreactive neurons in the deep layer of the dorsal horn gradually increased to a peak 24 hours after operation, then decreased to the normal level 1 week after operation. The number of substance P and CGRP immunoreactive L5 and L6 dorsal root ganglion neurons were decreased markedly 1 week after the pain model operation. In conclusion, after neuropathic pain model operation, c-fos proteins were immediately expressed in the superficial layer of spinal dorsal horn, thereafter c-fos proteins in the deep layer of spinal dorsal horn were expressed. CGRP and substance P immunoreactive neurons in DRG were decreased markedly 1 week after neuropathic pain model operation. These decrements do not coincide with the other chronic pain models, which show great increases in these pain transmitting substances. Therefore, the relationship between pain and c-fos, SP and CGRP should be investigated further.

Induction of Fos protein immunoreactivity by spinal cord contusion

The objective of the present study was to identify neurons in the central nervous system that respond to spinal contusion injury in the rat by monitoring the expression of the nuclear protein encoded by the c-fos gene, an activity-dependent gene, in spinal cord and brainstem regions. Rats were anesthetized with urethane and the injury was produced by dropping a 5-g weight from 20.0 cm onto the exposed dura at the T10-L1 vertebral level (contusion group). The spinal cord was exposed but not lesioned in anesthetized control animals (laminectomy group); intact animals were also subjected to anesthesia (intact control). Behavioral alterations were analyzed by Tarlov/Bohlman scores, 2 h after the procedures and the animals were then perfused for immunocytochemistry. The patterns of Fos-like immunoreactivity (FLI) which were site-specific, reproducible and correlated with spinal laminae that respond predominantly to noxious stimulation or injury: laminae I-II (outer substantia gelatinosa) and X and the nucleus of the intermediolateral cell column. At the brain stem level FLI was detected in the reticular formation, area postrema and solitary tract nucleus of lesioned animals. No Fos staining was detected by immunocytochemistry in the intact control group. However, detection of FLI in the group submitted to anesthesia and surgical procedures, although less intense than in the lesion group, indicated that microtraumas may occur which are not detected by the Tarlov/Bohlman scores. There is both a local and remote effect of a distal contusion on the spinal cord of rats, implicating sensory neurons and centers related to autonomic control in the reaction to this kind of injury.

Immunoreactivity of androgen receptor protein in sexually dimorphic spinal motonucleus in neonatal male rats

The spinal motonucleus of the genitofemoral nerve regulating scrotal temperature can also be related to prenatal and neonatal testicular descent by gubernacular change in rats, and a sexually dimorphic-like bulbocavernosus/dorsolateral motonucleus. There is a hypothesis that neonatal androgen affects these motonuclei, and induces development of sexual organs through neural stimulation. Until now, the accumulation of isotope-labelled androgen and the immuno-reactivity of androgen receptor protein in each sexually-dimorphic spinal motonucleus have been revealed in adult rats but they have not been established in rats during neonatal periods. To investigate the presence of the androgen receptor in spinal sexually-dimorphic motonuclei in the neonatal period, we evaluated the androgen receptor immunoreactivity of these motonuclei. In Sprague-Dawley male rats, the lumbar spinal cords were resected at postnatal days 3, 10 and 30, and stained immunohistochemically using polyclonal antibody of androgen receptor protein. The immunoreactivity of androgen receptor protein was observed in the cells of the genitofemoral motonucleus from the 13th thoracic to the 2nd lumbar spinal cord and the bulbocavernosus/dorsolateral motonucleus was observed from the 4th to 5th lumbar spinal cord in all age groups. The proportional areas of both motonuclei at days 3 and 10 on cross-section were larger than at day 30. The motonuclei at days 3 and 10 were similar in all age groups. With the above results, the presence of androgen receptor protein was confirmed in the genitofemoral and bulbocavernosus/dorsolateral motonucleus from neonate to day 30. The larger proportional area of these motonuclei in neonates may indicate an active role for these motonuclei during the neonatal period. Although the immunoreactivity does not directly imply the presence of a functional receptor, neonatal androgen could be responsible for the development of sexual organs through the spinal motonucleus.

Immunohistochemical study of the expression of human groEL-stress protein in human nervous tissue.

Monoclonal antibody (ML-30) directed against 65 kDa stress protein of mycobacteria, is shown to identify human cellular protein homologous with the groEL heat shock protein in many prokaryotes. Immunohistochemical survey of nervous tissue, both central and peripheral, from patients dying of various inflammatory, degenerative and neoplastic conditions and from experimental animals, using this antibody showed punctate granular staining of the cells to a variable degree. The astrocytes showed strong immunolabelling. The normal neurons and oligodendroglia stained variably, while abnormal neurons were darkly labelled. Ependymal cells showed apical granular positivity. The ubiquitinated inclusion bodies in amyotrophic lateral sclerosis, Alzheimer's disease and Parkinson's disease were not recognised by the ML-30 antibody. In diseased and stressed nervous tissue from experimental animals, the expression of the ML-30 recognisable stress protein was variable. The epitope recognised by ML-30 was found stable in postmortem tissues collected up to 36 h after death and processed for paraffin sectioning, after fixation in formalin for many years. Enhanced expression of the human groEL stress protein homologue in mammalian nervous tissue following various forms of stress may play a role in modulating the extent of tissue damage by autoimmune mechanism because of its high immunogenic nature and constitutive presence in the cells.

Incriase of the serotonin metabolite, 5-hydroxyindoleacetic acid, in cerebro-spinal fluid and spinal cord of bovines affected with the paraplegic syndrome

The paraplegic syndrome of bovines is a condition characterized by impairment of locomotion, hypoalgesia and finally death within 72 h. The pathogenesis of the syndrome has not been established. In the present work we determined the levels of monoamines and their metabolites in cerebro-spinal fluid and spinal cord of affected animals in order to investigate the functional state of these neurotransmitters. The content of the main metabolite of serotonin, 5-hydroxyindoleacetic acid, was elevated in the cerebro-spinal fluid and in the gray matter of the spinal cord of paraplegic bovines. Serotonin content in the spinal cord did not differ with respect to control animals, but was decreased in the cerebro-spinal fluid of affected animals. Modifications in the noradrenergic system were also observed, but were less consistent, for which reason further studies are needed. These observations indicate an increase in the turnover rate of serotonin in the paraplegic syndrome. The meaning of the described alterations is unknown at the moment

Cytochemical changes in spinal cord and testis of mice during starvation

The effect of starvation on the content and distribution of RNA, proteins and glycogen of spinal cord and testis of mice was studied. Spinal cord and testis were taken from mice, non-starved and after one, two and three days of total starvation. In the neurons of the spinal cord, starvation decreased RNA and proteins early in the fast, decreases in glycogen occurred more slowly, late in the fast. In the testis there was no obvious decrease in RNA and proteins content and a very slight decrease of the glycogen granules, i.e. the mice conserve testis RNA, proteins and glycogen during prolonged starvation. It has been found that the effect of starvation on RNA, protein and glycogen of the testis and spinal cord was variable

Fatty acid composition and dynamics of phospholipids from fresh water fish Prochilodus Lineatus brain and spinal cord

Se estudió la composición de fosfolípidos y ácidos grasos de lípidos de cerebro y médula del pez de de agua dulce Prochilodus lineatus (sábalo). También hemos investigado la anisotropía de fluorescencia de fosfolípidos marcados con 1.6-difenil-1.3.5 hexatrieno. Se halló que la fosfatidilcolina era el fosfolípido más abundante, seguido por la fosfatidil etanolamina, fosfatidil-serina, fosfatidil-inositol y la esfingomielina. La composición de ácidos grasos de todos los fosfolípidos, exceptuando la esfingomielina, mostró la presencia de ácidos no saturados de la series n-3, n-6 y n-9. El ácido araquidónico evidenció la presencia de ácidos grasos polinosaturados de la serie n-6, y se lo encontró preferentemente en el fosfatidil-inositol. Los ácidos grasos n-3 fueron representados por los ícidos 20:5n-3, (araquidónico) y 3 en peces de agua dulce contrasta con la ausencia de los n-6 en el tejido nervioso de peces marinos. La fosfatidilcolina mostró la mayor fluidez de todos los fosfolípidos de cerebro y médula