ABSTRACT
The EEG has been widely employed in the assessment of electrophysiological changes induced by distinct medications. Its sensibility in detecting alterations produced by a specific substance may be enhanced by methods of quantitative analyses (qEEG). The present study aimed at investigating the modulatory effects of bromazepam on brain dynamics. The effects of bromazepam (3mg) on EEG power distribution were tested in 10 healthy individuals, in a double-blind experiment. The electrophysiological measure was analyzed across experimental conditions, moments, and electrodes, in the delta, theta, alpha and beta frequency bands separately. A significant decrease of relative power was observed in delta and theta (main effect of condition). No interactions were observed. Although the expected anxiolytic EEG profile was not observed (increased beta and decreased alpha activity), this specific result may be related to other factors such as dosage used and the subjects' general physiological state, and not necessarily to the drug itself.
O EEG tem sido amplamente empregado na avaliação de mudanças eletrofisiológicas induzidas por medicações distintas.A sensibilidade desta técnica em detectar alterações produzidas por uma substância pode ser aprimorada por métodos de análise quantitativa (EEGq). O presente estudo teve por objetivo investigar os efeitos modulatórios do bromazepam na dinâmica cerebral. Os efeitos de 3mg de bromazepam na distribuição de potência cortical foram observados em 10 indivíduos sadios, em um desenho duplo-cego. A medida eletrofisiológica foi analisada nas diferentes condições experimentais, momentos e eletrodos, em delta, teta, alfa e beta separadamente. Uma diminuição significativa de potência relativa foi observada em delta e teta (efeito principal para condição). Não foram observadas interações. Embora o perfil ansiolítico do EEG (aumento de beta e diminuição de alfa) não tenha sido observado, esteresultado específico pode estar relacionado a outros fatores, tais como dose utilizada e estado fisiológico dos sujeitos, e não necessariamente à droga propriamente dita.
Subject(s)
Adult , Female , Humans , Male , Anti-Anxiety Agents/pharmacology , Bromazepam/pharmacology , Electroencephalography/drug effects , Motor Cortex/drug effects , Analysis of Variance , Double-Blind Method , Motor Cortex/physiologyABSTRACT
Benzodiazepines are among the most commonly prescribed medications due to their therapeutic efficacy in reducing anxiety and inducing sleep. Consequently, they have been widely employed in the pharmacological treatment of several disorders. Nevertheless, few studies have analyzed the effects of bromazepam in electroencephalographic activity (EEG). The present study aimed at investigating the modulatory effects of this drug on brain dynamics. Specifically, the effects of bromazepam (3mg) on EEG coherence were tested in a double-blind experiment. The sample, consisting of 10 healthy subjects (5 male and 5 female), was submitted to ten minutes of EEG recording. The electrophysiological measure (coherence) was analyzed across three experimental conditions: bromazepam, placebo 1, and placebo 2. Results indicate that bromazepam significantly increases cortical interhemispheric coherence.
Benzodiazepínicos estão entre as medicações mais comumente prescritas devido à sua eficácia terapêutica para reduzir ansiedade e induzir sono. Conseqüentemente, eles têm sido amplamente empregados no tratamento de diversas desordens. No entanto, poucos estudos têm analisado os efeitos do bromazepam na atividade eletrencefalográfica (EEG). Assim, o presente estudo teve por objetivo investigar os efeitos modulatórios desta droga na dinâmica cerebral. Especificamente, os efeitos de 3 mg de bromazepam na coerência eletrocortical foram analisados em um experimento duplo-cego. A amostra consistiu de 10 sujeitos sadios (5 homens e 5 mulheres), submetidos a dez minutos de captação do sinal de EEG. A medida eletrofisiológica (coerência) foi analisada em três condições experimentais: bromazepam, placebo 1 e placebo 2. Os resultados sugerem que o bromazepam aumenta significativamente a coerência cortical inter-hemisférica.
Subject(s)
Adult , Female , Humans , Male , Anti-Anxiety Agents/pharmacology , Bromazepam/pharmacology , Electroencephalography/drug effects , Functional Laterality/drug effects , Motor Cortex/drug effects , Double-Blind MethodABSTRACT
Chronic intracortical perfusion of GABA (Gamma Amino Butyric Acid) and its subsequent withdrawal generates, the GABA withdrawal syndrome (GWS). This particular epileptic model has been observed in the motor cortex of monkeys and rats. Our purpose was to study the GWS in the motor cortex (MC), dorsal hippocampus (DH), and superior colliculus (CS). Thirty chronically-implanted adult Wistar rats were separeted into 3 groups of 10 (8 experimental and 2 controls). The first group received GABA in MC, the second in the DH and the third in the SC. GABA was released in doses of 10 to 60 mug/mul/h for 6 days employing osmotic mini-pumps. Two control rats per group received saline solution in the above-mentioned structures. Rats perfused in the MC showed GWS after interruption of the GABA flow. The group perfused in the DH showed paroxysmal discharges and epileptic seizures during perfusion. They also later showed GWS. No epileptic effects were observed in the SC-perfused group during either the GABA perfusion or during withdrawal. None of the six control animals showed epileptic effects. Our results show that the SC offers a strong resistance to GWS. This could be explained by the particular neuronal network structure of rat SC.