ABSTRACT
Objetivo. Evaluar el Espesor de la Capa de Fibras Nerviosas de la Retina(ECFNR), Índice excavación/papila(E/P), Desviación media(DM) e Índice de Función Visual(VFI)enojos con reciente conversión perimétrica y compararlos con sus adelfos pre- perimétricos. Método. Estudio transversal.Se estudiaron 62 pacientes, 15 con glaucomainicial perimétrico unilateral(G/P), 11 con reciente conversión perimétrica unilateral(RC/P)y 36pacientes con sospecha de glaucoma( P/P), todos con adelfo pre-perimétrico.Cada 6-12 meses se obtuvieron imágenes con elTomógrafo de Coherencia Óptica (SD-OCT) yPerimetría Computarizada Convencional. Se determinó el ECFNR, E/P, DM y VFIde cada ojo y el cocientey la diferencia de ECFNR delos cuadrantes superior e inferior de cada ojo con los cuadrantes de su adelfo pre-perimétrico. Resultados. En el grupo (P/P) las diferencias de ECFNR en ambos cuadrantes con sus homólogos adelfosnormalesfueron< del 14%con <14 micras de diferencia. Mientras que en el grupo (CR/P) fueron > del 19%con >23 micras de diferencia y en el grupo (G/P)> 23.2% con >26micras de diferencia.Cuando comparamos con un adelfo pre-perimétrico pero con cuadrante Borderline/Patológico, puede haber conversión campimétricacon mínimas diferencias deECFNR 0-5%. Conclusión. La conversión perimétrica se presenta al traspasar límites que podemos calcular con el SD-OCT. Una disminución de 13-19% del ECFNR del cuadrante superior o inferior en comparación con su homólogo adelfo (verde según la base de normalidad del OCT) produciría comienzo de la expresión campimétrica. El conocimiento de estos escenarios clínicos puede ser útil en el manejo de la progresión del glaucoma (AU)
Purpose. Assessand compare Retina Nerve Fiber Layer (RNFL) thickness, Cup/Disc Ratio(C/D), Mean deviation (MD) and Visual field index (VFI) in recent cases ofconversion to perimetric glaucoma. Methods. Cross sectional study. The authors studied 62 patients, 15 unilateral initial perimetric glaucoma(G/P), 11 cases of recentunilateral conversion to perimetric glaucoma (CR/P)and 36 glaucoma suspects patients (P/P).Visual fields and OCT images were obtained every 6 to 12 months. RNFL thickness, C/D, MD, VFI and the rate and difference between superior and inferior cuadrants RNFL thickness with their corresponding pre-perimetric fellow eye cuadrants were computed. Results. (P/P) group RNFL thickness differences between superior and inferior cuadrants with corresponding cuadrants from their fellow eyes were < 14% (<14 micras), while in (CR/P) were > 19% and in (G/P) > than 23% with >26 micras of difference. When we compare to a pre-perimetric fellow eye cuadrant classified as borderline/pathologic, visual field defects could appear with minimum RNFL thickness differences (3-5%). Conclusión. Conversion to perimetric glaucoma occurs when certain thresholds are crossed. These limits could be estimated with SD-OCT.A 13-19% RNFL thickness decrease of superior or inferior cuadrants could produce visual field defects appearance.Knowledge of these clinical settings could be helpful in glaucoma management (AU)
Subject(s)
Humans , Glaucoma/physiopathology , Nerve Fibers/physiology , Retinal Neurons/physiology , Visual Fields , Disease Progression , Cross-Sectional Studies , Tomography, Optical CoherenceABSTRACT
Subthreshold electrical stimulation of the amygdala (kindling) activates neuronal pathways increasing the expression of several neuropeptides including thyrotropin releasing-hormone (TRH). Partial kindling enhances TRH expression and the activity or its inactivating ectoenzyme; once kindling is established (stage V), TRH and its mRNA levels are further increased but TRH-binding and pyroglutamyl aminopeptidase II (PPII) activity decreased in epileptogenic areas. To determine whether variations in TRH receptor binding or PPII activity are due to regulation of their synthesis, mRNA levels of TRH receptors (R1, R2) and PPII were semi-quantified by RT-PCR in amygdala, frontal cortex and hippocampus of kindled rats sacrificed at stage II or V. Increased mRNA levels of PPII were found at stage II in amygdala and frontal cortex, and of pro-TRH and TRH-R2, in amygdala and hippocampus. At stage V, pro-TRH mRNA levels increased and those of PPII, decreased in the three regions; TRH-R2 mRNA levels diminished in amygdala and frontal cortex and of TRH-R1 only in amygdala. In situ hybridization analyses revealed, at stage II, enhanced TRH-R1 mRNA levels in dentate gyrus and amygdala while decreased in piriform cortex; those of TRH-R2 increased in amygdala, CA2, dentate gyrus, piriform cortex, thalamus and subiculum and of PPII, in CAs and piriform cortex. In contrast, at stage V decreased expression of TRH-R1 occurred in amygdala, CA2/3, dentate gyrus and piriform cortex; of TRH-R2 in CA2, thalamus and piriform cortex, and of PPII in CA2, and amygdala. The magnitude of changes differed between ipsi and contralateral side. These results support a trans-synaptic modulation of all elements involved in TRH transmission in conditions that stimulate the activity of TRHergic neurons. They show that reported changes in PPII activity or TRH-binding caused by kindling relate to regulation of the expression of TRH receptors and degrading enzyme.
Subject(s)
Amygdala/physiology , Gene Expression Regulation/physiology , Kindling, Neurologic , Thyrotropin-Releasing Hormone/physiology , Animals , Base Sequence , DNA Primers , Male , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Wistar , Receptors, Thyrotropin-Releasing Hormone/genetics , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
PURPOSE: To study the success of visual rehabilitation in a group of 1,000 patients with low vision. METHOD: Clinical data on visual rehabilitation was studied in 1,000 subsequent patients suffering from visual impairment. Study focused on ocular disease, improvement in visual acuity and successful use of visual aids. A statistical analysis of results is presented. RESULTS: 25 cases dropped out due to issues in primary diagnosis. Remaining 975 patients were assigned to 9 groups: age-related macular degeneration (339) diabetic retinopathy (264 cases), myopic maculopathy (195 cases), glaucoma (96 cases), congenital maculopathy (39 cases), retinal detachment (12 patients), retinitis pigmentosa (13 cases), macular pucker (6 patients) and a miscellaneous group of 11 cases. The overall success in the improvement in visual acuity was 98% except for a group of patients with retinitis pigmentosa where a rate of only 46% success (p<0.01) was observed. 76% of cases finally accepted visual rehabilitation aids. CONCLUSIONS: The usefulness of visual rehabilitation in low vision patients is confirmed, with the exception of retinitis pigmentosa cases, probably due to features of the disease itself. The design of visual aids should be improved in order to benefit a greater number of patients.
Subject(s)
Lenses , Vision, Low/rehabilitation , Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Humans , Male , Middle Aged , Patient Satisfaction , Vision, Low/etiologyABSTRACT
Objetivo: Estudiar el éxito en la adaptación de ayudas visuales en un grupo de 1.000 pacientes afectos de baja visión. Métodos: Analizamos los datos clínicos de 1.000 pacientes remitidos a un Centro de Baja Visión para la adaptación de ayudas visuales, y los resultados de dicha adaptación en relación con la patología ocular de base, tanto respecto a la mejoría de agudeza visual (AV) como a la aceptación definitiva de la ayuda visual. Al objeto de poder extraer conclusiones útiles sometimos los datos a un análisis estadístico. Resultados: Del grupo inicial tuvieron que descartarse 25 casos por deficiencias en el diagnóstico de referencia. El grupo final de 975 pacientes fue subdividido en 9 grupos: afectos de degeneración macular asociada a la edad (339 casos), retinopatía diabética (264 pacientes), maculopatía miópica (195 casos), glaucoma (96 pacientes), maculopatías congénitas (39 casos), desprendimiento de retina (12 pacientes), retinosis pigmentaria (13 casos), membrana epirretiniana macular (6 pacientes) y un último grupo afecto de patologías diversas (11 casos). El éxito global (mejoría de AV) en la adaptación de las ayudas visuales fue del 98 por ciento, excepto en el grupo afecto de retinosis pigmentaria, con sólo un 46 por ciento (p<0,01). Un 76 por ciento de los pacientes aceptaron finalmente el empleo de las ayudas visuales. Conclusiones: Se confirma la utilidad del empleo de ayudas visuales para mejorar la agudeza visual en pacientes afectos de baja visión, exceptuando los casos de retinosis pigmentaria, probablemente debido a las propias características de la enfermedad. Se constata asimismo la necesidad de mejoras en el diseño de dichas ayudas visuales, al objeto de que puedan beneficiar a un mayor número de pacientes (AU)
No disponible
Subject(s)
Middle Aged , Child , Adult , Adolescent , Aged , Aged, 80 and over , Male , Female , Humans , Lenses , Vision, Low , Patient SatisfactionABSTRACT
PURPOSE: To analyze the effect of prolonged (daily) electrical vagus nerve stimulation (VNS) on daily amygdaloid kindling (AK) in freely moving cats. METHODS: Fifteen adult male cats were implanted in both temporal lobe amygdalae, both lateral geniculate bodies, and prefrontal cortices. A bipolar hook (5-mm separation) stainless steel electrode also was implanted in the unsectioned left vagus nerve. AK only was performed on five of the cats as a control. The remaining 10 cats were recorded under the following experimental conditions: VNS (1.2-2.0 mA, 0.5-ms pulses, 30 Hz) for 1 min along with AK (1-s train, 1-ms pulses, 60 Hz, 300-600 microA), followed by VNS alone for 1 min, four times between 11:00 a.m. and 2 p.m. At different times, VNS was arrested, and AK was continued until stage VI kindling was reached. RESULTS: The behavioral changes evoked by VNS were as follows: left miosis, blinking, licking, abdominal contractions, swallowing, and eventually yawning, meowing, upward gaze, and short head movements. Compulsive eating also was present with a variable latency. Outstanding polygraphic changes consisted of augmentation of eye movements and visual evoked potentials while the animal was awake and quiet, with immobility and upward gaze. An increase of the pontogeniculooccipital (PGO) wave density in rapid eye movement (REM) sleep also was noticeable. AK was completed (to stage VI) in the control animals without a vagus nerve implantation in 23.4+/-3.7 trials. In animals with VNS, the AK was significantly delayed, remaining for a long time in the behavioral stages I-III and showing a reduction of afterdischarge duration and frequency. Stage VI was never reached despite 50 AK trials, except when the vagus nerve electrodes were accidentally broken or vagal stimulation was intentionally arrested. Under these circumstances, 24.4+/-8.16 AK trials alone were necessary to reach stage VI of kindling. CONCLUSIONS: Our results indicate that left, electrical VNS interferes with AK epileptogenesis. This anticonvulsant effect could be related to the increase of REM sleep.
Subject(s)
Behavior, Animal/physiology , Electroencephalography , Epilepsy/etiology , Kindling, Neurologic/physiology , Temporal Lobe/physiopathology , Vagus Nerve/physiology , Amygdala/physiology , Amygdala/physiopathology , Animals , Cats , Electric Stimulation , Epilepsy/physiopathology , Male , Polysomnography , Sleep, REM/physiology , Temporal Lobe/physiologyABSTRACT
PURPOSE: Thyrotropin-releasing hormone (TRH), present in extra hypothalamic brain areas, has been proposed to have neuromodulatory functions and to be susceptible to change by electrical stimulation paradigms. We measured TRH concentrations of several brain areas during kindling development before its establishment and determined whether the changes detected in TRH levels were related to the behavioral stages of kindling, the number of stimulations required to reach these stages and, with the electrophysiological parameters characteristic of this paradigm (amygdaloid afterdischarge (AD) frequency, duration, and propagation). METHODS: Male Wistar rats were implanted stereotaxically with indwelling bipolar electrodes in the basolateral nucleus of the amygdala and with two stainless-steel electrodes epidurally in frontal cortex. Amygdaloid kindling was induced by daily electrical stimulation; AD frequency and duration were recorded and analyzed throughout the development of kindling. TRH was extracted from several regions and quantified by radioimmunoassay (RIA). RESULTS: Modifications in TRH concentrations were detected, depending on the region assayed, from stage II of kindling. A positive correlation was noted between the levels of TRH and the frequency and propagation of AD, but not with the number of stimulations. The rate of change in TRH concentration in relation to AD frequency or duration was highest in frontal cortex followed by hippocampus and amygdala. CONCLUSIONS: A graded response was noted in the increase in TRH concentration dependent on the increase of AD frequency and propagation. The rate of response correlated with the region's epileptogenic susceptibility.
Subject(s)
Amygdala/chemistry , Brain Chemistry , Electroencephalography , Epilepsy/metabolism , Kindling, Neurologic/metabolism , Thyrotropin-Releasing Hormone/analysis , Amygdala/metabolism , Amygdala/physiology , Animals , Electric Stimulation , Electrophysiology , Epilepsy/physiopathology , Frontal Lobe/chemistry , Frontal Lobe/physiology , Functional Laterality/physiology , Hippocampus/chemistry , Hippocampus/physiology , Kindling, Neurologic/physiology , Male , Radioimmunoassay , Rats , Rats, Wistar , Thyrotropin-Releasing Hormone/biosynthesisABSTRACT
The aim of this single-blind study was to evaluate the residual effects of a 10-mg dose of diazepam on cortical activation 11 h after oral intake. The electroencephalographic segments (from O1-O2) delimited by a sequence of photic stimuli presented every 10 sec during a simple reaction-time task (36 min duration) were arbitrarily classified into nine cerebral patterns (EEGP). EEGP segment classifications were grouped into six peri-stimulus transitions expressed in percentages: alpha-blockade; alpha-persistence; beta-persistence; alpha-induction; activation and deactivation. A sample of 42 young healthy university students (21 females and 21 males) each underwent three counterbalanced experimental conditions (control, placebo and diazepam). Diazepam affected all the subjects, although the women showed a greater number of EEGP transitions which indicated deactivation, than did the men. The results show that this type of visual EEG analysis is a useful technique for detecting the residual effects of benzodiazepines.
Subject(s)
Brain/drug effects , Diazepam/pharmacology , Electroencephalography/drug effects , Hypnotics and Sedatives/pharmacology , Adult , Brain/physiology , Female , Humans , Male , Sex Factors , Single-Blind Method , Time Factors , Visual Perception/drug effects , Visual Perception/physiologyABSTRACT
The effect of repeated Na-penicillin (PCN) microinjections in the temporal lobe amygdala (AM) of free-moving cats was investigated in order to establish if kindling epileptogenesis is possible with this procedure. The cortical propagation of the PCN-induced post-discharge in AM and the sequence of behavioral changes induced by PCN were similar to those of AM electrical kindling. Nevertheless, the epileptogenic effect of PCN had a different evolution from that of electrical kindling, since some PCN habituation was observed after several doses. Repeated microinjections of PCN did not produce lasting alterations in sleep onset and organization. The only mild changes recorded in the 23 h following PCN microinjections were an increased latency of the first rapid eye movement (REM) sleep episode, a SWS II total time and percentage increase, and, with the highest PCN doses, a not very significant diminution of REM sleep total time. Another finding was the occurrence of REM sleep ponto-geniculo-occipital (PGO) waves, coinciding with a depression of the frequency and amplitude of interictal amygdaloid and cortical spikes. The results showed that a microinjection of PCN in the AM produced a reliable model of interictal spikes, paroxysms and generalized convulsive seizures. Nevertheless, long lasting kindling effect was not observed.
Subject(s)
Amygdala/physiology , Brain Mapping , Electroencephalography/drug effects , Epilepsy/chemically induced , Penicillins/pharmacology , Polysomnography/drug effects , Amygdala/anatomy & histology , Animals , Behavior, Animal/drug effects , Cats , Drug Administration Schedule , Epilepsy/psychology , Male , Microinjections , Penicillins/administration & dosage , Sleep/drug effects , Sleep/physiologyABSTRACT
Penicillin-G has been used as a common agent to produce epileptic foci and interictal activity. The development of the interictal spikes has been associated with enhanced inhibitory effects. There is evidence that the opioid peptides play an important role in the production of some transient postictal behaviors. In order to test whether enkephalins are involved during the interictal activity, we analyzed immunoreactive met- and leu-enkephalin content and their release in vitro, after the injection of 50 IU of penicillin-G into the left amygdala. Male Wistar rats were injected once daily for 5 days, and sacrificed by decapitation (15 min after the penicillin-G infusion) on the fifth day. The rats were divided into two groups: 1. In one group we analyzed the tissue content of enkephalins in hypothalamus, hippocampus, amygdala, striatum and cerebral cortext. 2. The second group was used for the assessment of the in vitro release of enkephalins from amygdala slices. In the amygdala, the drug treatment produced an increase in the tissue content of IR-ME. No changes occurred in the other structures. The content of IR-Leu-enkephalin increased in all structures analyzed except the cerebral cortex. In vitro release of both enkephalins increased in drug treated animals. These results suggest that the enkephalins could be involved in postictal mechanisms, as a result of repetitive interictal spiking.
Subject(s)
Brain/drug effects , Enkephalin, Leucine/metabolism , Enkephalin, Methionine/metabolism , Amino Acid Sequence , Amygdala/drug effects , Amygdala/metabolism , Animals , Brain/metabolism , Convulsants , Evoked Potentials/drug effects , In Vitro Techniques , Male , Molecular Sequence Data , Penicillin G , Rats , Rats, Wistar , Time FactorsABSTRACT
Pyroglutamyl peptidase II (PPII) is a neuronal ectoenzyme responsible for thyrotropin releasing hormone (TRH) degradation at the synaptic cleft. PPII, heterogeneously distributed in different brain regions and adenohypophysis, is regulated under various endocrine conditions where TRH is involved in thyrotropin or prolactin regulation but only at the adenohypophyseal level. TRH can downregulate PPII activity in cultured adenohypophyseal cells. TRH present in extrahypothalamic brain areas has been postulated to serve as a neuromodulator and levels of this peptide increase in amygdala, hippocampus and cortex after electrical stimulation (kindling or electroshock). To study whether brain PPII could be regulated in conditions that stimulate TRHergic neurons, TRH and PPII activity were determined during the development of amygdaloid kindling in the rat. TRH levels increased from stage II to V in amygdala and hippocampus in the ipsi- and contralateral side to stimulation. In n. accumbens a decrease, compared to sham was observed at stage II, but levels raised through stage V. In contrast, PPII activity was increased at stage II, in amygdala of both sides and in hipppocampus, frontal cortex, n. accumbens and hypothalamus of the contralateral side; levels decreased at stage V to sham values in most structures (except amygdala and hippocampus where the activity was 30% below controls). These results suggest that PPII activity in the central nervous system can be regulated in conditions known to affect TRHergic neurons.
Subject(s)
Aminopeptidases/metabolism , Amygdala/physiopathology , Kindling, Neurologic/physiology , Thyrotropin-Releasing Hormone/metabolism , Analysis of Variance , Animals , Electric Stimulation , Male , Pyrrolidonecarboxylic Acid/analogs & derivatives , Rats , Rats, WistarABSTRACT
EEG frequency and time domain color maps were computed during amygdala kindling in cats. The pattern of the amygdala afterdischarge (AM/AD) propagation to the cortex was assessed as kindling evolved. Our results show that the AM/AD has 4 components that coincide with the activation of certain cortical areas during specific behavioral stages. The pattern of the cortical projection follows an asymmetrical temporo-fronto-occipital direction, the ipsilateral temporal lobe being the first activated zone, followed by the ipsilateral and contralateral prefrontal areas. The contralateral temporal activation is a late phenomenon. We conclude that the electrographic and behavioral manifestations of this model of complex partial epilepsy are asymmetrical during the whole process, including the convulsive stage.
Subject(s)
Amygdala/physiology , Brain Mapping , Cerebral Cortex/physiology , Electroencephalography/drug effects , Kindling, Neurologic/physiology , Temporal Lobe/physiology , Animals , Cats , Electrodes , Male , Neural Pathways/anatomy & histology , Neural Pathways/physiology , Regression Analysis , Stereotaxic TechniquesSubject(s)
Epilepsy/physiopathology , Models, Chemical , Models, Neurological , Amino Acids/physiology , Animals , Anticonvulsants/pharmacology , Anticonvulsants/therapeutic use , Biogenic Monoamines/physiology , Cerebral Cortex/physiopathology , Electroencephalography , Endorphins/physiology , Epilepsy/drug therapy , Epilepsy/genetics , Epilepsy/metabolism , Epilepsy/pathology , Glutamate Decarboxylase/physiology , Glutamates/physiology , Glutamic Acid , Humans , Kindling, Neurologic/drug effects , Sleep/physiology , Synapses/physiology , gamma-Aminobutyric Acid/physiologySubject(s)
Sleep Wake Disorders/physiopathology , Sleep/physiology , Humans , Sleep Apnea Syndromes/classification , Sleep Apnea Syndromes/physiopathology , Sleep Apnea Syndromes/therapy , Sleep Stages/physiology , Sleep Wake Disorders/classification , Sleep Wake Disorders/therapy , Sleep, REM/physiologySubject(s)
Amygdala/physiology , Kindling, Neurologic/drug effects , Penicillins/pharmacology , Amygdala/anatomy & histology , Animals , Brain/anatomy & histology , Catheterization , Cats , Decerebrate State/physiopathology , Electric Stimulation , Electroencephalography , Epilepsies, Partial/chemically induced , Epilepsies, Partial/physiopathology , Penicillins/administration & dosageABSTRACT
1. The effects produced by repetitive i.v. administration of naloxone (1, 2 or 4 mg/kg) on the visual evoked potentials (VEPs) recorded along the main and accessory visual pathways were investigated in a modified "encéphale isolé" cat preparation. 2. Naloxone provoked a progressive amplitude enhancement and latency reduction of some components, depending on the structure analyzed, the dose used and the number of administrations applied. Electroretinogram (ERG) and N1-P1 VEP components of optic chiasm (OCh), lateral geniculate body (LGB) and visual cortex (VC) did not present significant changes. 3. Late-latency components (more than 200 msec) appeared in the VEPs of LGB and VC, mainly when 4 mg/kg were used. 4. Our results suggest that endogenous opioids have a modulatory role in the processing of sensory information at different levels of the visual system.
Subject(s)
Evoked Potentials, Visual/drug effects , Naloxone/pharmacology , Visual Pathways/drug effects , Animals , Cats , Decerebrate State , Electroencephalography , Electroretinography , Female , Male , Photic StimulationSubject(s)
Epilepsy/physiopathology , Kindling, Neurologic/physiology , Adolescent , Adult , Animals , Cats , Child , Child, Preschool , Electric Stimulation , Electroencephalography , Female , Guinea Pigs , Humans , Ileum/physiology , Male , Rats , Spinal Cord/physiology , Temporal Lobe/physiology , Thalamus/physiologyABSTRACT
The sustained inhibitory action of spinal endorphins could be responsible for the habituation of polysynaptic responses in the spinal cord. To test this hypothesis, acute spinalized unanesthetized cats (decerebrated and curarized) were used. Sural nerve electrical stimulation (0.2 Hz) was provided and a progressive decrease in the reflex response was found. Conversely, the field potential (lamina V) progressively increased during stimulation, reaching its maximum amplitude when ventral root response showed maximum habituation. The administration of naloxone (0.8-10.0 mg/kg) produced dehabituation or prevented habituation. The immunohistological results showed leu-enkephalin-like immunoreactive dot-like structures in close proximity to neurons of laminae VII, VIII and IX in the lumbo-sacral segment of the spinal cord. Our results suggest an involvement of opioid peptides in the habituation process.
Subject(s)
Enkephalins/pharmacology , Habituation, Psychophysiologic/drug effects , Naloxone/pharmacology , Reflex/drug effects , Spinal Cord/physiology , Animals , Cats , Decerebrate State , Electric Stimulation , Enkephalin, Leucine/analysis , Evoked Potentials , Immunoenzyme Techniques , Spinal Cord/analysis , VagotomyABSTRACT
The effect of repetitive administration of naloxone on the development of massed amygdaloid kindling in 'encéphale isolé' cats was studied. Electrical amygdaloid kindling was carried out with a 15 min inter-stimulus interval (ISI) in a control situation with intravenous (i.v.) naloxone administration (2, 4, and 8 mg/kg), 5 min prior to amygdaloid stimulation. It was found that it was possible to complete the amygdaloid kindling process in the encéphale isolé preparation reaching generalized electrographic tonic-clonic self-sustained seizures. The enhancement of the duration, frequency, and propagation of the after-discharge (AD) was accentuated by naloxone which also induced a progressive amplitude increment of the first potential evoked by the onset of the tetanus. The number of trials needed to achieve seizure generalization was reduced in dose-dependent manner by naloxone. The ability of naloxone to accelerate the development of amygdaloid kindling may be related to an inhibitory role of opioid peptides in this process.
Subject(s)
Convulsants/pharmacology , Decerebrate State/physiopathology , Endorphins/physiology , Kindling, Neurologic/drug effects , Naloxone/pharmacology , Seizures/metabolism , Amygdala , Animals , Cats , Female , Male , Seizures/physiopathologyABSTRACT
This study analyzed the effects of 1 week administration of alprazolam (AL; 0.25 mg), lorazepam (LO; 1 mg) and placebo (PL) on sleep as well as their residual effects on attention upon awakening. Under a crossed, double-blind design, six healthy male volunteer subjects between 19 and 30 years of age were studied. After two habituation sessions and a control session, each substance was given orally, twice a day for 7 days, with a 1-week washout period between administrations. At the end of each administration period, sleep studies were conducted from 2300 to 0700 hours. Evaluation of attention was carried out by means of a simple visuomotor reaction time (RT) task, and a time estimation (TE) task, that started at 0700 hours, lasting 1 h. Neither drug significantly affected any sleep variable. Both benzodiazepines tended to increase RT, but only LO did so significantly at the beginning of the attention test. No significant changes in predictive and failure responses during the RT task were produced by either drug. Also, no significant changes were observed in the TE. Even though only LO produced a significant increase of RT at the selected doses and with 1 week administration, it is suggested that both benzodiazepines could have residual effects on attention.
