ABSTRACT
Endothelial cells are directly involved in many functions of the cardiovascular system by regulating blood flow and blood pressure through Ca2+ dependent exocitosis of vasoactive compounds. Using the Ca2+ indicator Fluo-3 and the patch-clamp technique, we show that bovine adrenal medulla capillary endothelial cells (B AMCECs) respond to acetylcholine (ACh) with a cytosolic Ca2+ increase and depolarization of the membrane potential (20.3±0.9 mV; n=23). The increase in cytosolic Ca2+ induced by 10µM ACh was mimicked by the same concentration of nicotine but not by muscarine and was blocked by 100 µM of hexamethonium. On the other hand, the increase in cytosolic Ca2+ could be depressed by nifedipine (0.01 -100 µM) or withdrawal of extracellular Ca2+. Taken together, these results give evidence for functional nicotinic receptors (nAChRs) in capillary endothelial cells of the adrenal medulla. It suggests that nAChRs in B AMCECs may be involved in the regulation of the adrenal gland's microcirculation by depolarizing the membrane potential, leading to the opening of voltage-activated Ca2+ channels, influx of external Ca2+ and liberation of vasoactive compounds.
Subject(s)
Animals , Cattle , Adrenal Medulla/drug effects , Calcium Channels/drug effects , Cytosol/drug effects , Endothelial Cells/drug effects , Nicotine/pharmacology , Receptors, Nicotinic/drug effects , Acetylcholine/pharmacology , Adrenal Medulla/blood supply , Adrenal Medulla/cytology , Calcium Channels/metabolism , Capillaries/cytology , Capillaries/drug effects , Cytosol/metabolism , Evoked Potentials/drug effects , Hexamethonium/pharmacology , Membrane Potentials/drug effects , Muscarine/pharmacology , Receptors, Nicotinic/metabolismABSTRACT
Caffeine is one of the most widely consumed stimulant drugs of the modern world. It brings about a feeling of well-being, relaxation, increased alertness and concentration. Its effects have been studied on brain function and behavior using mood questionnaires, reaction time tests, memory tests, EEG and of late Event Related Potentials (ERPs). This study evaluates the response of caffeine on ERPs and Reaction Time (RT) using auditory "oddball" paradigm. Forty undergraduate medical students volunteered for the study and their ERPs and RT were recorded before and after 40 minutes of ingestion of caffeine. There was a non-significant decrease in latency of N1, P2, N2 and P3 and a significant decrease in Reaction Time after caffeine consumption. The amplitude of P3 showed a significant increase after intake of caffeine. The results of this study indicate that caffeine leads to facilitation of information processing and motor output response of the brain.
Subject(s)
Adolescent , Adult , Brain/drug effects , Caffeine/pharmacology , Cognition/drug effects , Evoked Potentials/drug effects , Humans , Male , Reaction Time/drug effects , Receptors, Dopamine/drug effects , Receptors, Purinergic P1/drug effectsABSTRACT
Although there is extensive literature about the effects of stimulants on sustained attention tasks in attentional deficit/hyperactivity disorder (ADHD), little is known about the effect of these drugs on other attentional tasks involving different neural systems. In this study we measured the effect of stimulants on ADHD children, both in the electroencephalographic (EEG) activity during sustained attentional tasks and in psychometric performance during selective attentional tasks. These tasks are known to rely on different cortical networks. Our results in children medicated with 10 mg of d-amphetamine administered 60 min before the study indicate (i) a significant increase in amplitude but not latency of the P300 component of the event-related potential (ERP) during the sustained attentional task and (ii) a significant improvement in the reaction times and correct responses in the selective attentional task. In addition to supporting the use of stimulants in children with attentional deficit/hyperactivity disorder, these results show a multifocal activity improvement of cortical structures linked to dopamine, and interestingly, to attention. All these analyses are framed in a wider study of diverse attentional functions in this syndrome.
Subject(s)
Humans , Male , Female , Child , Adolescent , Attention Deficit Disorder with Hyperactivity/drug therapy , Attention/drug effects , Central Nervous System Stimulants/therapeutic use , Dextroamphetamine/therapeutic use , Electroencephalography , /drug effects , Evoked Potentials/drug effects , Reaction TimeABSTRACT
Short latency somatosensory evoked potentials were measured in 10 patients with Parkinson's disease before and after tha administration of Apomorphine 5 mg sc. Eight of these subjects were reassessed after one month of treatment with Levo-dopa. These potentials were measured in other nine subjects before and after one month of treatment with Selegiline 10 mg od. There was a significant increase of frontal potential N30 in nine of 10 subjects that received apomorphine, in seven of 8 patients treated with Levodopa and 7 of 9 patients treated with Selegiline. No changes in N20 parietal potential were observed. During apomorphine test, changes in N30 potential preceded clinical improvement in 6 patients and occurred simultaneously in 3 patients. No changes with apomorphine in N30 potential were observed in 2 healthy males. There was no relationship between electrophysiological changes and duration of disease or motor fluctuations. It is concluded that short latency somatosensory evoked potentials are an objective means of measuring dopaminergic response in patients with Parkinson's disease
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Parkinson Disease/drug therapy , Apomorphine/pharmacokinetics , Evoked Potentials/drug effects , Selegiline/pharmacokinetics , Levodopa/pharmacokineticsABSTRACT
Nuestra población es llevada por la propaganda a consumir productos que argumentan combatir la fatiga, la debilidad nerviosa, mental y muscular, disminución de la capacidad intelectual, depresión psíquica, proporcionando deseos de trabajar y estudiar, reactiva la memoria, aumenta la capacidad de concentración, y mejorar la capacidad mental, los cuales hemos denominado "NEUROTONICOS". Evaluamos el efecto de los neurotónicos (CERENERVON), usando 2 médidas estándar de la función nerviosa, la velocidad de conducción periférica del nervio cubital y el tiempo de conducción del sistema nervioso central (SNC) por medio de potenciales evocados somatosensoriales (PESS)
Subject(s)
Adult , Neurotransmitter Agents/analysis , Neural Conduction , Evoked Potentials/drug effectsABSTRACT
El autor describe, de manera general, algunos conceptos básicos referentes a la definición, origen y desarrollo de la etnopsiquiatría, así como las relaciones que ésta disciplina guarda con la antropología médica. Se señala la importancia de no considerar a la etnopsiquiatría como un mero catálogo de hechos doblemente extraños (en tanto que problemas psiquiátricos y en tanto que provenientes de otra cultura). La definición de etnopsiquiatría que se propone es "el estudio de las relaciones entre las conductas psicopatológicas y las culturas en las cuales éstas últimas se inscriben". Se destaca que las perspectivas de desarrollo de la etnopsiquiatría en México son extremadamente vastas
Subject(s)
Cats , Endorphins/pharmacology , Endorphins , Electronarcosis , Evoked Potentials/drug effects , Cerebrum/drug effects , Naloxone/pharmacology , Naloxone , Visual PerceptionSubject(s)
Anesthesia , Central Nervous System/physiology , Electrocardiography/drug effects , Electroencephalography/drug effects , Evoked Potentials, Auditory/drug effects , Evoked Potentials, Visual/drug effects , Evoked Potentials/drug effects , Monitoring, Physiologic/methods , Intracranial PressureABSTRACT
The effect of intraventricularly administered GABA on hippocampus was investigated by recording its electrical activity after chronic implantation of cannulae and bipolar electrode in five male beagle dogs. GABA was introduced in 40 mg/Kg b. weight so as to exceed its physiological levels in CSF. Recordings were made within two hours after microinjection in third ventricle. The predominant pattern of EEG depicted synchronization. The progressing synchronization of EEG suggests induction of functional lesion which might be playing a protective role in the regulation of metabolic behaviour.
Subject(s)
Animals , Dogs , Electroencephalography/drug effects , Evoked Potentials/drug effects , Hippocampus/drug effects , Injections, Intraventricular , Male , gamma-Aminobutyric Acid/drug effectsABSTRACT
La oclusión palpebral ante un estímulo auditivo sorpresivo es una respuesta refleja [RAP] polisináptica de integración mesencefálica que tiende a desaparecer frente a estímulos repetidos. Este reflejo transcurre a través del núcleo coclear, cuerpo trapezoide, collículo inferior y sus conexiones, y está sujeto a influencias supramesencefálicas. En el estudio presente, se evaluaron electrofisiológicamente 6 individuos normales y 6 pacientes con enfermedad de Parkinson de edades similares. Se aplicaron estímulos tonales registrándose la actividad refleja en el orbicular de los párpados. Se midieron latencia [L], duración [D], amplitud [A] y fases [F] de las respuestas reflejas obtenidas por aplicación de estímulos auditivos a intervalos randomizados, y luego de un período de reposo, se midió el número de respuestas obtenidas [R] aplicando los estímulos a una frecuencia fija de 0,2 Hz. No se observaron diferencias significativas en L,D,A y F, viéndose en cambio, un mayor número de R en los enfermos de Parkinson. Esta observación sugiere una alteración en la habituación a los estímulos auditivos posiblemente debida a fallas en la inhibición de este reflejo por compromiso de estructuras supramesencefálicas
Subject(s)
Parkinson Disease/complications , Inferior Colliculi , Cochlear Nerve , Reflex, Acoustic , Parkinson Disease/drug therapy , Blinking , Levodopa/therapeutic use , Reflex, Abnormal/physiopathology , Evoked Potentials/drug effects , Neural Pathways/physiology , Neural Pathways/physiopathologyABSTRACT
Recientemente hemos demostrado que la administración de diversos compuestos con potencia alucinógena producen una actividad de onda y espiga a 6 c/s en algunas estructuras del sistema limbico del gato. Los animales simultáneamente a la aparición de esta actividad despliegan movimientos de exploración dirigidos hacia objetos que no son detectados por los observadores
Subject(s)
Cats , Animals , Evoked Potentials/drug effects , Photic Stimulation , Limbic SystemABSTRACT
The findings in this study suggest that there is defect in the neuromuscular transmission in hyperthyroidism. This abnormality was detected in 62 per cent of the patients and did not directly correlate with proximal muscle weakness present in most of the patients. It seems that the weakness in hyperthyroidism is the result of myopathy as well as neuromuscular transmission both of which might be due to the same metabolic derangement but are not directly related. After treatment, the muscle power became normal in all of the patients and the neuromuscular transmission was normalized in most but not all of them. It is possible that this transmission defect may be due to other mechanisms apart from the hormonal disorder e.g. the same processes as that which occurs in myasthenia gravis. The underlying pathophysiology is worth further exploration.
Subject(s)
Adult , Curare/diagnosis , Evoked Potentials/drug effects , Female , Humans , Hyperthyroidism/physiopathology , Male , Middle Aged , Myasthenia Gravis/physiopathology , Neuromuscular Junction/physiology , Synaptic Transmission/drug effectsSubject(s)
Adolescent , Adult , Middle Aged , Humans , Male , Female , Alcuronium/pharmacology , Atracurium/pharmacology , Atropine/pharmacology , Muscle Contraction , Electromyography , Evoked Potentials/drug effects , Halothane , Neostigmine/pharmacology , Neuromuscular Blocking Agents/pharmacologyABSTRACT
Se analizan estudios recientes para investigar el valor de los potenciales evocados somatosensitivos, en la evaluación de diversos procedimientos de anestesia regional. Los datos hasta ahora disponibles sugieren que el bloqueo de la conducción nerviosa en las fibras rápidas es menor de lo que cabría esperar de acuerdo a la extensión cefálica de la analgesia al pinchazo en anestesia raquídea o epidural lumbar con bupivacaina. Las dosis convencionales de bupivacaina en anestesia epidural torácica no tienen virtualmente efecto sobre los potenciales evocados aunque se presente analgesia quirúrgica. La Morfina epidural no parece ser capaz de modular los potenciales evocados tempranos tras la estimulación eléctrica en las metámeras afectadas por el fármaco. La infiltración de troncos nerviosos periféricos con anestésicos locales es más efectiva que los demás procedimientos respecto a interrumpir la transmisión del estímulo en las vías exploradas por medio de potenciales evocados. Se necesita mayor caudal de investigaciones para evaluar el valor de esta técnica en el estudio de los bloqueos regionales, centrales y periféricos
Subject(s)
Bupivacaine , Evoked Potentials/drug effects , Morphine , Nerve BlockSubject(s)
Humans , Male , Female , Evoked Potentials/drug effects , Nausea/drug therapy , Plants, Medicinal , Vertigo/drug therapy , Eye Movements , Heart Diseases , Hypertension , Plant ExtractsABSTRACT
En el presente trabajo se analiza el efecto de la aplicación de picrotoxina en el área cortical de proyección de focos penicilínicos corticales o de respuestas transcallosas evocadas por estimulaciones eléctricas (PFP y RET respectivamente); antes, durante y después de ondas de depresión cortical propagada (DCP). Los resultados muestran que la picrotoxina provoca aumento en la amplitud de las RET y PFP, sobre todo a punto de partida del componente negativo de estas respuestas; durante las ondas de DCP, se observó depresión inicial de las respuestas evocadas, seguido de variaciones del componente negativo y positivo. Se discuten los resultados sobre la base de la acción de la picrotoxina en las sinapsis inhibitorias corticales