ABSTRACT
Antecedentes. Los efectos deletéreos de suprimir la oxigenación de los tejidos se pueden eliminar con protección celular, utilizando alimentos como el pescado, que contiene litio, ácidos grasos, omega 3, frutas y verduras para aportar antioxidantes. La regeneración celular y tisular se puede mediar por encefalinas. Su acción puede asociarse al ejercicio físico intenso y el trabajo excéntrico encargados de retirar los tejidos lesionados. Objetivo. Conocer algunas experiencias que utilizan la inmersión en piscina para suprimir el dolor y dar calidad de vida al paciente. Materiales y métodos. Se analiza la interacción de diez variables utilizadas como herramientas de trabajo en ocho pacientes escogidos al azar. Resultados. El trabajo excéntrico es la más importante de las herramientas. El daño muscular produce factor de crecimiento muscular y nervioso, lo cual, junto al empleo de insulinas, regenera en conjunto los tejidos. La herramienta de los endocanabinoides participa en la relajación, protección, alimentación y re-funcionalización de los tejidos, a la par que interactúa con las endorfinas para mediar la reparación en el sistema endotelial. Conclusiones. Las imágenes funcionales avanzadas (3 Teslas) de resonancia serán de utilidad para observar y evaluar las interacciones de las herramientas.
Background. Cell protection removes the deleterious effects of suppressing tissue oxygenation by using foods such as fish, which contains lithium, fatty acids, omega 3, fruits and vegetables that provide antioxidants. Enkephalins mediate cell and tissue regeneration. Strenuous exercise and eccentric work are related to enkephalins action in charge of removing the damaged tissues. Objective. To present some professional experiences that use the pool immersion to suppress the pain and to improve the life quality of the patient. Materials and methods. Analysis of ten variables interaction, used as working tools in eight randomly selected patients. Results. Eccentric work is the most important tool. Muscle damage produces nervous and muscle growth factor which, by the use of insulins regenerate tissue altogether. The variable endocannabinoids participates in relaxation, protection, feeding and re-functionalization of tissues; it also interacts with endorphins to mediate the repair in the endothelial system. Conclusions. We conclude that advanced functional imaging (3 Tesla) with resonance would be useful to observe and evaluate the interactions of the variables.
ABSTRACT
Biochemical and behavioral evidence indicates that the dopaminergic mesolimbic system plays a key role in the mechanisms of reinforcement and reward elicited by alcohol (ethanol) and other drugs of abuse. In addition, the dopaminergic activity of the nigrostriatal pathway has been proposed to determine brain sensitivity to ethanol, a process which could be associated to drug addiction. Besides dopamine, several neurotransmitters and neuromodulators are involved in ethanol reinforcement, including gamma aminobutyric acid (GABA), glutamate, serotonin, acetylcholine and opioid peptides (enkephalins, endorphins and dynorphins). Ethanol and opioids share several pharmacological properties and exhibit similar behavioral effects in animals and humans. These and other studies suggest that the alcohol reinforcing properties are due, at least in part, to the ethanol-induced activation of endogenous opioidergic systems. This activation could in turn increase the hedonic value and the reinforcing effects of the drug. Thus, ethanol-induced changes in opioidergic transmission could contribute to alcohol intoxication and to the neuroadaptive responses produced by the long-lasting exposure to the drug. Opioidergic transmission may be altered by ethanol at different levels, including biosynthesis, release and inactivation of opioid peptides, as well as binding of endogenous opioids to their receptors. Several studies suggest that mu and delta opioid receptors play a key role in ethanol reinforcement and dependence. Therefore, enkephalins and (β-endorphin could mediate ethanol actions in the brain and play a major role in high alcohol drinking behavior. During the last years, our research group has focused on the role of the endogenous opioid systems in these processes. Evidence obtained in our laboratory suggests that enkephalins and (β-endorphin differentially and selectively participate in ethanol reinforcement and dependence.
Evidencias bioquímicas y conductuales indican que el sistema dopaminérgico mesolímbico cumple un papel fundamental en los mecanismos de reforzamiento y recompensa del alcohol (etanol) y otras drogas de abuso. Se ha propuesto también que la actividad de la vía dopaminérgica nigroestriatal determina la sensibilidad cerebral a etanol, lo que parece estar directamente relacionado con los procesos de adicción a la droga. Además de la dopamina, varios neurotransmisores y neuromoduladores están implicados en los mecanismos de reforzamiento del etanol, entre ellos, el ácido gama-aminobutírico (GABA), el glutamato, la serotonina, la acetilcolina y los péptidos opioides (encefalinas, endorfinas y dinorfinas). El alcohol y los opioides comparten características farmacológicas y exhiben efectos similares sobre el comportamiento en animales y en el hombre. Éstos y otros estudios sugieren que las propiedades reforzadoras del etanol se deben, al menos parcialmente, a la activación de los sistemas endógenos de péptidos opioides, proceso que es inducido por el propio alcohol. Esta activación podría, a su vez, aumentar el valor hedónico y los efectos reforzadores de la droga. Los cambios inducidos por etanol sobre la transmisión de opioides podrían contribuir de manera importante a los procesos de intoxicación y a las respuestas neuronales adaptativas que produce el consumo prolongado de la droga. La transmisión opioidérgica puede ser afectada por etanol a distintos niveles, incluyendo la biosíntesis, liberación e inactivación de los opioides endógenos, así como la unión de éstos a sus receptores. Numerosas evidencias sugieren que los receptores opioides mu y delta desempeñan un papel fundamental en el reforzamiento y la dependencia al etanol. Así, las encefalinas y la (β-endorfina actuarían como mediadores fisiológicos de las acciones del etanol en el cerebro, desempeñando un papel crucial en las conductas de alto consumo de la droga. En los últimos años, nuestro grupo se ha centrado en investigar el papel de los sistemas endógenos de péptidos opioides en estos procesos. Las evidencias obtenidas en nuestro laboratorio sugieren que las encefalinas y la (β-endorfina participan en forma diferencial y selectiva en el reforzamiento y la dependencia al etanol.
ABSTRACT
Since enkephalins discovery in 1975, several opioid peptides have been included in neuroscience research. Enkephalins have been involved in the homeostasis maintenance of the organism, mostly with cellular and molecular mechanisms implicated in antinociception and narcotic responses. Moreover, enkephalins have been shown to be involved in the control of stress, regulation of cardiovascular functions, modulating primary immune responses, in addition to cellular differentiation processes. As opioid peptides appear to modulate several bioactivities and physiological responses in organisms, this posits that several modifications should occur during their synthesis, cell release, and receptor binding in target cells. At present, it has been demonstrated that the endogenous opioid system (EOS), displays a circadian rhythm, in which its tissue content, presynaptic release, and receptor's number reaches its maximal concentration during the dark phase (24:00h) and the minimal during the early morning (05:00 h). Recently, our group reported that functional pinealectomy disrupts the enkephalin circadian rhythm and significantly reduces the tissue content of opioid peptides in the rat brain. However, the effect was shown to be specific to the hour along the 24h daytime. There were no significant changes during the light period, only during the dark period (01:00h), when the enkephalin tissue content decreased in the experimental group. The effect was reverted when pinealectomized rats were injected with single doses of melatonin (MEL) (150µg/kg i.p.). If the lack of melatonin in the rat brain significantly reduced the enkephalin tissue content, and its exogenous administration re-established the enkephalin tissue levels, it is possible that the hormone is involved in the enkephalin synthesis. In this paper we provide further evidence that supports the relation between melatonin and opioid peptides synthesis and release. In addition, we studied the effect of darkness and melatonin administration in enkephalin tissue levels. Finally, we analyzed the luzindole effect as a melatonin receptor antagonist in the pinealectomized rat brain. Material and methods Subjects: Male Wistar rats were housed in a light and temperature controlled room. Water and pellet food were available ad libitum. This group was subdivided in: 1. Functional pinealectomy group (FP). Rats were housed individually during 15 days in a room with continuous light (<50lux). 2. FP rats were housed in a dark room during four or six hours. 3. FP rats were injected with melatonin (150, 300, 600µg/kg s.c.). 4. FP rats were injected with Luzindole (187.5, 375, 750µg/kg i.p.). After 30 min, the animals were injected with melatonin (150µg/kg). 5. FP rats were injected with melatonin (800µg/ kg) and subjected to the in vitro release processes. The rats were sacrificed by decapitation and the blood collected for melatonin serum determination. The brains were removed and processed for an analytical preparative procedure for the enkephalin determination by radioimmunoassay technique. The in vitro release methodology was performed as follows: tissue samples were homogenized by applying 8 strokes with a Thomas grinder system. The homogenates were centrifuged at 4,000rpm, 4°C during 10 min. Supernatants were recovered and centrifuged at 12,000rpm at 4°C for 20 min. Supernatants were discarded and pellets were resuspended in the homogeneization buffer (1:9 w/v). Samples were placed on top of a Percoll gradient density (23%, 15%, and 10%) and centrifuged at 20,000 rpm at 4°C for 25min. The synaptosomal enriched fraction (15-23%) was obtained and diluted in 1mL of Krebs buffer (mM: NaCl 119, KCl 4.6, CaCl2·2H2O 1.25, KH2PO4 0.85 MgSO4 0.84, NaHCO3 24.8, sucrose 10). Buffer was gasified with a mixture of C0(2) 95% and O2 5%, pH 7.4. 800µL aliquots were placed into plastic chambers. After 20 min of stabilization with Krebs buffer, three different superfusates were collected: 1. basal, 2. potassium [50mM], and 3. post-stimulus (Krebs buffer without potassium). Samples were collected into HCl 0.1N, boiled and subsequently loaded into Amberlite XAD-2 columns (8 × 0.7cm) for solid-phase peptide extraction. The flow rate was held constant at 0.5 mL min-1 and elution of the whole peptide fraction was carried out using a continuous gradient with absolute methanol. Eluted samples were lyophilized and resuspended in 2mL of distilled water and finally stored at -20°C for further quantification of IR-Enkephalin using standard radioimmunoassay procedures. The results showed that functional pinealectomy reduced the opioid tissue content in the different brain structures assayed. The lack of melatonin significantly decreased the enkephalin tissue content when compared to the control group. However, tissue levels of enkephalin material were completely restored after four and six hours of administration of different doses of exogenous melatonin administration to the rats. As continuous light decreases the melatonin content in the brain, darkness should be able to counteract the aforementioned effect. Our results showed that tissue levels of enkephalin material were increased over 200% and 300%, after exposing animals to a four or six-hour period of darkness, when compared to animals exposed to continuous light. Luzindole was used to abolish any melatonin activity via activation of its membrane brain receptors. Our experiments showed that different doses of the antagonist were not able to obliterate the increased content of opioid peptides induced with melatonin administration in the tested brain tissues.
En la actualidad se reconoce que el Sistema Endógeno Opioide (SEO) participa en la regulación y control de la homeostasis; por lo tanto se requiere que los procesos bioquímicos que dan lugar a su síntesis, liberación y unión a receptores se encuentren reguladas de manera endocrina. Diversas líneas de investigación han demostrado que la concentración y liberación presináptica de las encefalinas no permanece constante durante un ciclo de 24 horas. Por el contrario, su síntesis y liberación alcanzan su máxima concentración durante la fase de oscuridad y la mínima durante las primeras horas de la mañana. Recientemente, nuestro grupo de trabajo ha demostrado que la ausencia de melatonina (MEL), por efecto de la pinealectomía funcional, rompe el ritmo circádico y reduce significativamente la concentración de las encefalinas durante la fase de oscuridad. Si la ausencia de la hormona abate la concentración de opioides, es factible que la MEL se encuentre involucrada en la síntesis de las encefalinas. En el presente trabajo se muestran los resultados del efecto de la pinealectomía funcional sobre la concentración tisular y la liberación de los opioides, así como el efecto de la administración exógena de MEL y de su antagonista el luzindol (LZ). Diseño experimental Control Naive. Se utilizaron ratas macho de la cepa Wistar (200-250g), que permanecieron en un cuarto con un ciclo de luz y oscuridad controlada. La fase de luz duró 12 horas y comenzó a las 06:00h. A su vez, este grupo fue subdividido en: 1. Luz Continua (LC): Para abatir la concentración sérica de la hormona, se usó el modelo experimental conocido como pinealectomía funcional. 2. Luz Continua + Oscuridad: La luz abate la concentración de MEL y la exposición a la oscuridad revierte dicho efecto. Un grupo de ratas sometido a la luz continua se colocó en un cuarto con oscuridad durante cuatro y seis horas. 3. Luz continua+melatonina: Para analizar el efecto de la MEL sobre el contenido tisular de opioides, se administró una dosis de MEL (150, 300 y 600µg/Kg s.c.). 4. Luz continua+luzindol (LZ)+MEL: Si la melatonina ejerce su mecanismo de acción al unirse a sus receptores presentes en la membrana plasmática, entonces su efecto podría ser revertido por la presencia del LZ. Por lo tanto, a tres grupos de ratas sometidas a la pinealectomía funcional se les inyectó con LZ a una dosis de 187.5, 375, 750 µg/kg. s.c. Después de transcurridos 30min., los animales fueron inyectados con MEL (150µg/kg. s.c.). 5. Liberación: Se utilizaron tres grupos de ratas: a) control, b) luz continua y c) luz continua+MEL (800µg/kg. s.c.). Post mortem la amígdala fue sometida al proceso preparativo para la obtención de los sinaptosomas. Resultados Los resultados obtenidos en el presente trabajo nos muestran que la pinealectomía funcional reduce significativamente la concentración de encefalinas en todas las estructuras cerebrales analizadas. Sin embargo, el efecto es revertido tanto por la administración exógena de MEL, como por la exposición a la oscuridad. Las diferentes dosis administradas del LZ bloquearon parcialmente el efecto estimulante de la MEL sobre la síntesis de los opioides. Por último, la pinealectomía funcional redujo significativamente la liberación presináptica de encefalinas, misma que se pudo reestablecer con la administración exógena de la hormona. Discusión Las evidencias experimentales del presente trabajo sugieren que la MEL se encuentra relacionada con la síntesis y la liberación de las encefalinas. Por un lado, la pinealectomía funcional redujo significativamente el contenido tisular de encefalinas, pero el efecto fue revertido tanto con la administración exógena de la hormona como con la exposición a la oscuridad. La administración del LZ sólo fue capaz de bloquear parcialmente el efecto estimulante de la MEL sobre la síntesis de encefalinas. El efecto de la MEL sobre la liberación de opioides pone de manifiesto la relación funcional entre ambos sistemas. A menor cantidad de opioides por efecto de la pinealectomía, menor liberación presináptica y por el contrario, una vez administrada la hormona los valores de la síntesis-liberación se restablecen. Conclusión La MEL puede estar involucrada en la síntesis y la liberación de los péptidos opioides.
ABSTRACT
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Abstract: Introduction. Epileptic activity modifies the endogenous opioid system by increasing its levels at the end of the ictal phase, and in post-ictal and interictal phases. This increase originates a cortical excitatory effect which suppresses both slow wave sleep and REM. The epileptic activity is initiated with the presence of interictal epileptiform activity, which may be induced through penicillin administration into amygdaline nuclei. Interictal epileptiform activity is a widely employed tool used to determine the localization of epileptic foci characterized by the sudden presence of spikes or acute waves in an electroencephalogram (EEG). In the present work, this tool was used to study the participation of the opioid system in the installation and propagation of epileptic activity induced in temporal lobe amygdala. In the epiloptogenetic study, amygdaline interictal epileptiform activity was used to assess changes induced by opioids and an antagonist in the occurrence of interictal activity using an event histogram. Propagation was studied with the cortical topographic mapping technique, which shows EEG frequency components in a power spectrum, as well as the rhythmic EEG patterns. The aim of the present study was to analyze the effect of enkephalins on epileptiform activity induced with penicillin in tem poral lobe amygdala and its propagation to the cerebral cortex. Method. Fifteen male Wistar rats were submitted to an acute preparation; they were anesthetized with urethane (1.2 g/kg, i.p.). A stainless steel bipolar electrode provided with a cannula was directed toward the left amygdaline basolateral nucleus and a second concentric bipolar electrode to the right amygdaline basolateral nucleus. Two types of cortical recordings were carried out: global mapping and restricted areas. The first consisted of the placement of a 16 stainless steel electrode matrix (in which the electrodes from the vertex were removed) on the scalp, taking care that the tips of the electrodes were in contact with the cortex; this arrangement covered the whole cerebral cortex. The second involved a 4x4mm square matrix consisting of 16 equidistant electrodes placed on the cerebral cortex. The cortical recording was a result of placing this matrix in four different positions so that the whole cerebral cortex was monitored. To monitor cortical recordings, experimental groups were injected penicillin into the amygdaline nuclei. To perform global mapping, enkephalins, [D-ala]-methionine and [D-ala]-leucine, were topically applied into the amygdaline nuclei and naloxone was administered systemically. Analogical signals were recorded in a video-tape and were digitized in parallel with an HP workstation. Off-line analysis was carried as follows: a) information recorded in video-tapes was acquired in a computer designed for this purpose, using amygdaline interictal epileptiform activity to plot event histograms; b) EEG digitized signal, obtained from global mapping, was used to obtain a spectral analysis, consisting of color images maps in time and frequency domains, using RBEAM software. The recording of electrical activity obtained with the square matrix was visually analyzed only. At the end of each experiment, animals were perfused and each brain was fixed intracardially with 10% formaldehyde. To verify the recording and sub-cortical injection sites, the rapid procedure was used. Results. During control stages, cortical records showed slow activity in the form of spindles in all the recording channels; this was due to urethane. Penicillin administration in amygdaline nuclei induced epileptiform activity with a specific pattern: immediate appearance after penicillin application with a gradual increase in amplitude until stabilization was reached within 5-10 minutes of administration. Analyses of global mapping in the frequency domain showed a specific mode of amygdaline interictal epileptiform activity propagation, starting in ipsilateral temporal, prefrontal and fron tal cortices, appearing subsequently in contralateral prefrontal and frontal cortices, and finally in temporal cortex. In the time domain spectrum, an electric dipole generating an interictal spike was found in cerebral cortex. Restricted areas mapping approach showed interictal epileptiform activity and its propagation along the ipsilateral fronto-temporal region. Data revealed an antero-posterior medial cortical activation spreading with decreasing intensity toward occipital regions. Application of enkephalins-[D-ala]-methionine and [D-ala]-leucine produced no epileptic activity, but an increase in basal EEG of cortical epileptiform activity was detected, as well as a decrease in amplitude and frequency of amygdaline epileptiform activity. Naloxone originated a facilitatory effect, since its administration induced focal and generalized electrocorticographic seizures. Conclusions. Focal penicillin is a reliable model of interictal spikes, paroxysms and generalized seizures. The study in rats showed a propagation of epileptic activity to prefrontal cortices prior to contralateral amygdala. Our results showed that enkephalins produced a double effect. First, they originated an increase in basal EEG in temporal cortical areas, as well as a putative participation in propagation mechanisms. Second, they exerted an inhibitory effect on epilepsy installation mechanisms. The inhibitory effect originated by enkephalins was reverted by naloxone.
