Citation

Joachim H. Blutalkohol 1976; 13(2): 111-131.

Copyright

(Copyright © 1976, International Committee on Alcohol, Drugs and Traffic Safety and Bund gegen Alkohol und Drogen im Straßenverkehr, Publisher Steintor Verlag)

DOI

unavailable

PMID

unavailable

Abstract

In order to investigate the influence of ethanol on the orbicularis oculi reflex during the phases of alcohol resorption and elimination, drinking experiments had been carried out with 20 male students. The drinks were given in an amount of 1 g/kg body weight within 75 min. The highest average blood concentration of ethanol was a little less than 100 mg%. The determination of the muscular potential of the reflex was performed by electrodes fixed on the skin above the foramen infraorbitale and the temporal canthus, and the potential was reproduced by a cathode ray oscilloscope. The reflex was elicited by mechanical and electrical stimulation. The electrical stimulus was performed with a rectangular current of 0.2 msec length. The following were the results: The threshold for the electrical stimulus rose during the phase of alcohol resorption rather quickly and was at its maximum, which was reached before the maximum of the blood alcohol level, nearly twice as high as at the beginning of drinking. The latency of the first component of the reflex (OOR-I) remained constant, whereas the latency of the second component (OOR II) was continuously growing longer during the phase of drinking. The components of the reflex behaved differently as to the effect of habituation: the OOR II, being ontogenetically the younger component, could be habituated more than usual after the very beginning of drinking and showed continuously increasing habituation, which took place at the OOR I only when the blood alcohol amounted to 70 to 80 mg%. Neither component recovered during the phase of alcohol elimination. These results confirm previous findings on the influence of alcohol on human psychophysical functions, but it could be proved, that ontogenetically younger parts of the central nervous system can be impaired by a lower concentration of ethanol than older parts, so that very low ethanol levels in the brain may severely influence some of its essential functions. It may be suggested, that the increasing habituation of the OOR II is due to an impairment of the functions of the ventral nucleus of the thalamus by alcohol, as neurons of the tract of the OOR II are supposed to be localized there. A beginning loss of self control, which can be observed after very low doses of alcohol, corresponds with these findings, as most of the pyramidal tracts are linked with the nuclei of the thalamus. An impairment of the intercentral neurons of the thalamus may lead to a disintegration of the activity of the neurons of the cortex. This effect probably results in a loss of self control in such a way that habitual patterns of thinking and decision are no longer efficient.

DWI