Effects of promethazine on the amplitude and spectral characteristics of electrocorticograms in rats

Pharmaco-EEG is a promising method for the study of drugs aimed at identifying their specific effect on the electrophysiological activity of the brain. This method can be used both for screening of new molecules and for detecting the still unexplored effect on the central nervous system of drugs used in clinical practice for a long time. The identification of dose-dependent effects is of particular interest in the context of studying the latter, since most of the drugs affecting the CNS can be prescribed to patients in different dosages depending on the severity or nature of the disease, which is associated either with an increase in their effectiveness or with an effect on additional targets. Since most of the psychotropic or neurotropic drugs of the first generations are non-selective and can bind to a large number of targets, a study using pharmaco-EEG can reveal both the main and side dose-dependent effects. Promethazine is a first-generation antihistamine, and in addition to the blockade of H1 receptors, its effect is also due to the blockade of M-cholinergic receptors, which is why a wide range of actions of this drug is associated. In this study, the effect of promethazine at different doses (0.5 mg/kg, 5 mg/kg and 20 mg/kg) on the amplitude-spectral characteristics of electrocorticograms in rats was evaluated, followed by analysis of the principal components. As a result, it was found that promethazine has a dose-dependent increase in the values of the main component PC1, which reflects the amplitude characteristics of electrocorticographic activity. At the same time, the effects of the drug on the spectral characteristics of the recorded signals were multidirectional and did not have statistical significance.