Action of diazepam on muscular contraction in man

Summary The action of diazepam has been examined in 18 healthy subjects by studying the correlation between electromyographically recorded mean voltage and isometric tension in skeletal muscle. A significantly increased slope of voltage tension curves was found after giving diazepam, i.e. the mean voltage at corresponding isometric tensions was about 20% higher. This finding is probably due to an action of the compound on contractile mechanisms.

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Zusammenfassung An Hand der Korrelation zwischen elektrischer Aktivität und isometrischer Spannung wurde die Wirkung von Diazepam auf den Skeletmuskel bei 18 gesunden Versuchspersonen studiert. Nach Diazepam wurde eine signifikante Zunahme der Steilheit der Regressionsgeraden gefunden, für eine bestimmte isometrische Spannung war die elektrische Aktivität um ca. 20% höher als vorher. Es wird eine direkte Wirkung der Substanz auf die kontraktilen Mechanismen postuliert.

     

Effects of therapy (diazepam, phenobarbital) on the E.E.G. in new-born babies during the first 24 hours of treatment (author's transl)]

The poor prognostic significance of inactive or paroxystic E.E.G. recordings in new-born babies appears to be well established (Monod et al., ibid., 1972, 32, 529-544). However, some cases have been described as having a favourable evolution even though such tracings had been proesent during the neonatal period. The authors studied, therefore, the effects of anticonvulsants (diazepam, phenobarbital) to see if they produced inactive or paroxystic tracings. A total of 19 new-born babies with convulsions of various etiologies were treated with phenobarbital and diazepam and recordings were made less than 24 hours after the beginning of treatment. Plasma levels were measured at the time of recording and varied from 3 to 26 micrograms/ml for phenobarbital and 0 to 2.75 micrograms/ml for diazepam. No paroxystic tracings were noted, but 2 inactive tracings were seen in infants who had been severely asphyxiated at birth, and in whom the plasma levels of the anticonvulants was found to be low. The injection of diazepam during the E.E.G. recording caused suppression of electrical discharges without notably altering the inter-seizure E.E.G. activity. The authors conclude that in the 19 cases studied the changes noted in the E.E.G. were related to the severity of the condition and were not secondary to therapy.