RESUMEN
BACKGROUND AND PURPOSE: Based on their proven ability, in animal models of stroke, to reduce damage to brain grey matter, many drugs have been tested in clinical trials but without success. Failure to save axons from injury and to protect functional outcome has been proposed as the major reason for this lack of success. We have previously demonstrated in two rodent models of cerebral ischaemia, that AS601245 (1,3-benzothiazol-2-yl (2-([2-(3-pyridinyl) ethyl] amino)-4 pyrimidinyl) acetonitrile), an inhibitor of the c-Jun NH(2)-terminal kinase (JNK), has neuroprotective properties. The aim of the present study was to further investigate if AS601245 in addition to its ability to protect neurons also could protect neurites and preserve memory after cerebral ischaemia, in gerbils. EXPERIMENTAL APPROACH: Using immunohistochemical techniques and a behavioural test, we studied the effect of the compound AS601245 on neurodegeneration and cognitive deficits after global cerebral ischaemia in gerbils. KEY RESULTS: At a dose of 80 mg kg(-1), i.p., AS601245 reduced damage to neurites by 67% (P<0.001 versus controls) and activation of astrocytes by 84% (P<0.001 versus controls). In addition, AS601245 (80 mg kg(-1), i.p.) prevented ischaemia-induced impairment of memory in the inhibitory avoidance task model. CONCLUSIONS AND IMPLICATIONS: The present results suggest that AS601245 reduced damage to neurites and decreased astrogliosis following global ischaemia and also improved long-term memory, supporting JNK inhibition as a promising therapeutic strategy for ischaemic insults to the CNS.
Asunto(s)
Acetonitrilos/farmacología , Axones/efectos de los fármacos , Benzotiazoles/farmacología , Isquemia Encefálica/tratamiento farmacológico , Trastornos del Conocimiento/prevención & control , Dendritas/efectos de los fármacos , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Fármacos Neuroprotectores/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Animales , Axones/patología , Isquemia Encefálica/patología , Dendritas/patología , Gerbillinae , Hipocampo/efectos de los fármacos , Hipocampo/patología , Masculino , Memoria/efectos de los fármacosRESUMEN
Clusterin is a protein involved in multiple biological events, including neuronal cytoprotection, membrane recycling and regulation of complement-mediated membrane attack after injury. We investigated the effect of recombinant human clusterin in preclinical models of peripheral neuropathies. Daily treatment with clusterin accelerated the recovery of nerve motor evoked potential parameters after sciatic nerve injury. Prophylactic or therapeutic treatment of experimental autoimmune neuritis rats with clusterin also accelerated the rate of recovery from the disease, associated with remyelination of demyelinated nerve fibers. These data demonstrate that clusterin is capable of ameliorating clinical, neurophysiological and pathological signs in models of peripheral neuropathies.
Asunto(s)
Clusterina/farmacología , Factores de Crecimiento Nervioso/farmacología , Regeneración Nerviosa/efectos de los fármacos , Nervios Periféricos/efectos de los fármacos , Enfermedades del Sistema Nervioso Periférico/tratamiento farmacológico , Animales , Clusterina/inmunología , Clusterina/uso terapéutico , Citocinas/efectos de los fármacos , Citocinas/inmunología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/fisiopatología , Femenino , Hipocampo/inmunología , Hipocampo/metabolismo , Hipocampo/patología , Ratones , Ratones Endogámicos C57BL , Proteína Básica de Mielina/efectos de los fármacos , Proteína Básica de Mielina/inmunología , Proteína Básica de Mielina/metabolismo , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/inmunología , Vaina de Mielina/patología , Factores de Crecimiento Nervioso/inmunología , Factores de Crecimiento Nervioso/uso terapéutico , Regeneración Nerviosa/inmunología , Neuronas/efectos de los fármacos , Neuronas/inmunología , Neuronas/patología , Técnicas de Cultivo de Órganos , Nervios Periféricos/inmunología , Nervios Periféricos/fisiopatología , Enfermedades del Sistema Nervioso Periférico/inmunología , Enfermedades del Sistema Nervioso Periférico/fisiopatología , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/farmacología , Proteínas Recombinantes/uso terapéutico , Neuropatía Ciática/tratamiento farmacológico , Neuropatía Ciática/inmunología , Neuropatía Ciática/fisiopatología , Resultado del TratamientoRESUMEN
Defibrotide is a polydeoxyribonucleotide sodium salt with antithrombotic properties. These properties have been attributed to its profibrinolytic activity [increase of tissue plasminogen activator (t-PA) activity, concomitant decrease of that of plasminogen activator inhibitor (PAI)], but there could conceivably be other factor(s). To look for these, we studied Defibrotide in a thrombosis model (pulmonary thromboembolism in mice) in which free radicals play a pivotal role. Defibrotide was found to be active after both intravenous and oral administration. Defibrotide behaved in vitro like a scavenger of H2O2 but not of O2.- in cell-free systems. Defibrotide added in vitro to cellular systems decreased the stimulated release of beta-glucuronidase from polymorphonuclear cells (PMNs), the luminol chemiluminescence induced by oxygen species generated by stimulated PMNs and the generation of O2.- from stimulated macrophages. We think that the antithrombotic activity of Defibrotide is based on other factor(s) in addition to profibrinolytic activity, i.e., some scavenger activity and desensitization of cells involved in thrombus formation must also be taken into account.
Asunto(s)
Fibrinolíticos/farmacología , Polidesoxirribonucleótidos/farmacología , Animales , Femenino , Glucuronidasa/efectos de los fármacos , Peróxido de Hidrógeno/metabolismo , Técnicas In Vitro , Mediciones Luminiscentes , Macrófagos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos DBA , Neutrófilos/efectos de los fármacos , Neutrófilos/enzimología , Embolia Pulmonar/inducido químicamente , Embolia Pulmonar/tratamiento farmacológico , Ratas , Ratas Wistar , Superóxidos/metabolismoRESUMEN
A human PET study was performed with carbon-11 labelled melatonin in a healthy volunteer. Plasma pharmacokinetics of melatonin and 6-sulfatoxymelatonin were simultaneously determined using radioimmunoassay. Analysis of tracer kinetics showed maximum activity in the brain 8.5 min following injection, which was different from the curve observed for the plasma radioactivity (maximum at 3.5 min). The results confirmed that melatonin readily crosses the blood-brain barrier and that 6-sulfatoxymelatonin is the main plasma metabolite. The distribution of tracer as a function of time in this study failed to reveal any specific binding.
Asunto(s)
Melatonina/farmacocinética , Adulto , Encéfalo/diagnóstico por imagen , Química Encefálica , Isótopos de Carbono , Humanos , Inyecciones Intravenosas , Masculino , Melatonina/administración & dosificación , Melatonina/efectos adversos , Melatonina/análogos & derivados , Radioinmunoensayo , Tomografía Computarizada de EmisiónRESUMEN
The distribution of [14C]melatonin [( 14C]MT) after systemic injection was studied in the plasma and brain of golden hamsters. Thin-layer chromatographic analysis indicated that the radioactivity of the biological samples taken at two different times following the injection of label was exclusively associated with [14C]MT. Representative autoradiograms revealed a heterogeneous localization of [14C]MT in the grey matter. Two min after injection, the highest regional values were found in the hippocampus, caudate-putamen, medial thalamus and choroid plexuses. Lower radioactive concentrations were observed in the cingulate and frontoparietal cortex, anterior thalamus, inferior colliculus, dorsolateral geniculate nucleus, lateral and medial hypothalamus and amygdala. Fifteen min after injection, a significant level of radioactivity remained in the hippocampus, caudate-putamen, ventral thalamus and hypothalamus area. The heterogeneous distribution and the partial retention of [14C]MT in the brain are compatible with the existence of specific brain binding sites for this hormone.
Asunto(s)
Encéfalo/metabolismo , Cricetinae/metabolismo , Melatonina/farmacocinética , Mesocricetus/metabolismo , Animales , MasculinoRESUMEN
The effects of the infusion of melatonin (MT) and/or of pinealectomy upon glucose utilization in anatomically discrete regions of the brain of freely moving rats have been studied by the quantitative autoradiographic 2-deoxy-D-[1-14C]glucose technique. The experiments were made from 14.00 to 16.00 h, when MT is normally not secreted by the pineal gland, in order to compare the local cerebral glucose utilization (LCGU) response to MT from animals with long-term (pinealectomized) or short-term (pineal intact) absence of MT secretion. The majority of the 98 brain areas examined showed no change in LCGU after MT administration and/or pinealectomy. Pinealectomy increased the LCGU in the median mammillary nucleus only, whereas following MT administration, an increase in LCGU was observed in 3 cerebral regions of intact rats (paraventricular nucleus of the hypothalamus, nucleus of the solitary tract, choroid plexus of the third ventricle) and in 5 cerebral regions of pinealectomized rats (paraventricular nucleus of the hypothalamus, nucleus of the solitary tract, choroid plexuses of the lateral ventricles, third and fourth ventricles). Except for the choroid plexuses of the fourth ventricle, there was no difference in LCGU response to MT between pinealectomized and intact animals. This does not favor the hypothesis of receptor supersensitivity under the conditions of this experiment. Our results suggest that the hypothalamus, nucleus of the solitary tract and choroid plexuses represent a neural substrate through which MT could influence the activity of the central nervous system when administered at a low dose under near-physiological conditions.
Asunto(s)
Encéfalo/metabolismo , Glucosa/farmacocinética , Melatonina/farmacología , Glándula Pineal/metabolismo , Animales , Encéfalo/efectos de los fármacos , Ventrículos Cerebrales/efectos de los fármacos , Ventrículos Cerebrales/metabolismo , Desoxiglucosa/farmacocinética , Hipotálamo/efectos de los fármacos , Hipotálamo/metabolismo , Masculino , Bulbo Raquídeo/efectos de los fármacos , Bulbo Raquídeo/metabolismo , Ratas , Ratas EndogámicasRESUMEN
Possible indirect components in the inhibition of firing of A9 dopamine neurons induced by systemic apomorphine were studied using unilateral drug administration through the internal carotid artery, known to irrigate only the ipsilateral mid- and forebrain. When compared to intravenous injection, unilateral intracarotid administration inhibited ipsilateral neurons with a marked decrease of both the latency (less than 1 s) and the dose required for complete inhibition, whereas contralateral neurons were not affected. This suggests a first-pass central effect of apomorphine, presumably associated with brain extraction. Thus, peripheral and hindbrain targets do not seem to contribute to the inhibitory effect of low doses of systemic apomorphine. An intranigral possible mode of action is discussed in view of the particular arrangement of dopaminergic dendrites within the zona reticulata.
Asunto(s)
Apomorfina/farmacología , Dopamina/fisiología , Inhibición Neural/efectos de los fármacos , Sustancia Negra/fisiología , Potenciales de Acción/efectos de los fármacos , Animales , Arterias Carótidas , Relación Dosis-Respuesta a Droga , Inyecciones Intraarteriales , Masculino , Ratas , Ratas Endogámicas , Sustancia Negra/efectos de los fármacosRESUMEN
The distribution of 14C-Melatonin (14C-MT) after systemic injection was studied in the plasma, cerebrospinal fluid (CSF), and brain of rats. Chromatographic analysis (thin-layer chromatography and high-performance liquid chromatography) indicated that the radioactivity from biological samples taken at various times following the injection of label was mainly associated with 14C-MT. Computer analysis of plasma 14C-MT kinetics showed a three-compartment system with half-lives of 0.21 +/- 0.05, 5.97 +/- 1.11, and 47.52 +/- 8.86 min. The volume of distribution and the clearance were 1,736 +/- 349 ml.kg-1 and 25.1 +/- 1.7 ml.min-1.kg-1 respectively. The entry of 14C-MT into the CSF was rapid and reached a maximum at 5 min. The decay followed a two-compartment system with half-lives of 16.5 +/- 2.9 and 47.3 +/- 8.6 min. The CSF/plasma concentration ratio was 0.38 at the steady state (30 min). At 2 min the level of 14C-MT in the brain was 3.8 higher than in the CSF. Representative autoradiograms revealed an heterogeneous localization of 14C-MT in the grey matter. The highest regional values, as evaluated by the permeability area product technique, were found in cortex, thalamic nuclei, medial geniculate nucleus, anterior pretectal area, paraventricular nucleus of the hypothalamus, choroid plexuses, and bulb-pons. Thirty minutes later 14C-MT was still detected in most of the brain regions analyzed. These results point to a low but rapid penetration of circulating MT into the brain and the CSF. The heterogeneous distribution and the partial retention of 14C-MT in the brain are compatible with the hypothesis of a central action of this hormone mediated via binding sites.
Asunto(s)
Encéfalo/metabolismo , Melatonina/farmacocinética , Animales , Autorradiografía , Barrera Hematoencefálica , Radioisótopos de Carbono , Cromatografía , Semivida , Cinética , Masculino , Melatonina/sangre , Melatonina/líquido cefalorraquídeo , Ratas , Ratas Endogámicas , Distribución TisularRESUMEN
A method has been developed for the simultaneous in vivo measurement of local rates for methionine incorporation into cerebral protein in the rat. It is based on the use of L-[35S]methionine as a tracer for reflecting the bidirectional exchange of methionine between plasma and brain and its incorporation into cerebral protein, using a dynamic three-compartment model. An operational equation based on this model has been derived in terms of determinable variables. The method has been applied to the normal freely moving rat and to the rat under chloral hydrate anesthesia. In the freely moving rat, the values of methionine incorporation into cerebral protein in the gray matter vary widely from structure to structure (50-300 nmol/100 g/min), with the highest values in structures related to neurosecretory functions, e.g., supraoptic and paraventricular nuclei. The values for white matter are more uniform (24-28 nmol/100 g/min) at levels approximately six- to seven-fold lower than for gray matter. Chloral hydrate anesthesia depresses the rate of methionine incorporation in all the structures examined. Anesthesia did not reduce the heterogeneity normally present within gray matter.
Asunto(s)
Encéfalo/metabolismo , Metionina/metabolismo , Modelos Neurológicos , Proteínas/metabolismo , Animales , Hidrato de Cloral , Cinética , Masculino , Matemática , Ratas , Ratas Endogámicas , Distribución TisularRESUMEN
The rate of methionine incorporation was measured in individual hypothalamic nuclei by a quantitative autoradiographic technique: the L-[35S]methionine method. Physiological stimulation of the hypothalamo-neurohypophysial system by two days of water deprivation, a stress that increased the plasma total neurophysins concentration 4-5-fold, resulted in a 70-80% increase in overall protein synthesis in the supraoptic nucleus and in the magnocellular subdivisions of the paraventricular nucleus. The same stimulus had no effect on protein synthesis rate of the suprachiasmatic nucleus and of the other representative cerebral structures examined. This differential effect on protein synthesis was also observed within the paraventricular nucleus.
Asunto(s)
Deshidratación/metabolismo , Hipotálamo/metabolismo , Proteínas del Tejido Nervioso/biosíntesis , Animales , Autorradiografía , Enfermedad Crónica , Sistema Hipotálamo-Hipofisario/metabolismo , Hipotálamo/citología , Masculino , Metionina , Neuronas/metabolismo , Núcleo Hipotalámico Paraventricular/metabolismo , Ratas , Ratas Endogámicas , Distribución TisularRESUMEN
A chronic arterial and venous cannulation method appropriate for pharmacokinetics studies in freely moving rats is described. Two catheters were implanted: one in the abdominal aorta, the other in the inferior vena cava. Passing subcutaneously, the catheters then emerged at the nape of the neck and were sealed by heating. In most cases (70%), 2-3 weeks after surgery, there were no problems of catheter patency. Twenty-four hours after surgery, all the animals were in good health as attested by normal behaviour and physiological parameters. Plasma corticosterone levels (544 +/- 219 ng/ml) determined at various times after an i.v. injection of saline, though 2.4-fold lower than in restrained rats (1330 +/- 292 ng/ml), were, however, indicative of a moderate stress. From a differential analysis of the factors involved in the relatively elevated circulating corticosterone as compared to basal levels, it is concluded that a prolonged postoperative period (7 days) and maintaining of the animals in metabolic cages are necessary conditions to obtain a minimal state of stress with this technique.
Asunto(s)
Encéfalo/metabolismo , Cateterismo/métodos , Farmacología/métodos , Anestesia General , Animales , Aorta , Glucemia/análisis , Catéteres de Permanencia , Corticosterona/sangre , Humanos , Masculino , Ratas , Estrés Psicológico/sangre , Procedimientos Quirúrgicos Operativos , Vena Cava InferiorRESUMEN
Incorporation of L-35S-methionine in brain proteins was measured by quantitative autoradiography in the rat. This model was checked by biochemical procedures. In awake freely moving rat, methionine incorporation rates vary from 36 to 258 nmol/100g/min. During anaesthesia, protein synthesis in brain decreases (30 to 50%).
Asunto(s)
Anestesia , Metionina/metabolismo , Proteínas del Tejido Nervioso/biosíntesis , Animales , Autorradiografía , Cinética , Masculino , Movimiento , Ratas , Ratas Endogámicas , Radioisótopos de Azufre , Distribución TisularRESUMEN
A beta-endorphin (beta END)-containing pituitary adenoma was demonstrated by immunocytochemical, biochemical, and ultrastructural methods in a 43-yr-old man who had impotence, slight testicular atrophy, and an enlarged sella turcica (grade II0), but no manifestations of Cushing's disease. Preoperative hormone data revealed hyperprolactinemia (97 ng/ml), low plasma cortisol levels without circadian rhythm, undetectable plasma ACTH, and normal plasma FSH and LH levels, with an impaired response to LRH. After hypophysectomy, these hormone levels normalized and responded normally to dynamic tests. Immunocytochemically, 30% of the tumor cells reacted only with beta END antiserum. beta END immunoreactivity was the only component revealed by RIA and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A characteristic ultrastructural aspect is also described. These findings demonstrate dissociation in the secretion of the proopiomelanocortin-derived peptides and suggest a relationship between hyperprolactinemia and tumor secretion of beta END.