SOME EFFECTS OF l‐HYOSCINE HYDROBROMIDE ON POST‐ROTATORY SENSATION AND NYSTAGMUS IN MAN

Abstract

In a balanced double‐blind trial six subjects were given, on three successive days, an injection of 0·3 mg. or 0·6 mg. of l‐hyoscine hydrobromide or normal saline, 30 min. before rotational tests of vestibular function were performed. Hyoscine caused a significant (P = 0·01) depression of the ‘slope’ of the sensation cupulogram without alteration of the extrapolated ‘threshold’. This effect was not significantly greater with the higher dose of the drug. In subjects who had received hyoscine there was an appreciable suppression of the post‐rotational nystagmic response, and slow pendular oscillations of the eyes were frequently recorded. These effects were antagonized by mental arithmetic. It was concluded that hyoscine increased adaptation in the vestibular sensory system and released the oculomotor system from the ascending influence of vestibular and reticular projections. © 1968 The Physiological Society