No abstract

It has been suggested that melatonin may have therapeutic potential for alleviating jet lag. In an attempt to define further the effects of low pharmacological doses of melatonin on the human body, 5 mg of melatonin was given orally to one subject in a blind experiment. The electrocardiogram (ECG) was recorded together with simple reaction time (SRT) responses over a 5-h period after taking melatonin. The main part of the project was carried out under artificial domestic lighting conditions and involved ten evening sessions. Microprocessor analysis of the ECG of one subject clearly showed that melatonin had the effect of lengthening the RR interval, that between the peak of the P wave and the onset of the R wave, and the interval between the onset of the R wave and the peak of the T wave. A model to explain the cubic curve, which was fitted by regression analysis to the data, implies that the natural evening increase in melatonin may also increase these intervals. The results suggest that melatonin may affect both the phase and the amplitude of the observed ECG phenomenon. Analysis of more than 40,000 SRT responses to both visual and auditory stimuli implied that these responses might also be lengthened by melatonin. Frequency histograms of the responses and observations on premature and missed responses were not able to reproduce the results of other workers who found that higher doses (240 mg) of melatonin decreased the number of incorrect responses to simple reaction time tasks.

SUMMARY1. Longitudinal studies on absolute pitch estimates have been observed in one male and two female subjects.2. The female subjects underwent rhythmic variations in their estimates that were related to their menstrual cycles. One female subject, the more intensively studied of the two, also showed variations in her pitch estimates that were related to illness.3. Relevant correlations between the menstrual cycle and known biochemical parameters are mentioned which suggest that the fluctuations in the female estimates are governed by changes in the electrical activity of the auditory nervous system. 4. The male subject showed similar fluctuations in his pitch estimates. A rhythm of approximately 20 days was observed.5. A connexion between the fluctuations in the pitch estimates and the sex hormones in both the female and the male subjects is suggested as a possible explanation of the difference between two different types of absolute pitch.6. The hypothesis is extended to show how the adrenal corticosteroids could account for the changes in the pitch estimates that occurred with illness.