GLUCOSE AND OXYGEN UTILIZATION IN SYMPATHETIC GANGLIA 109 



sistance or susceptibility in various cells or cell groups — perhaps one should 

 say metabolic differences from group to group — but the overall picture is fairly 

 constant. The structural similarity can also be shown to be associated with func- 

 tional likeness. No one, for example, would deny certain similarities in behavior 

 of a person suffering from oxygen want to one under the influence of alcohol or 

 narcotics (at certain stages). In a narrower sense, we appear to be dealing with 

 various phases of a cell problem which has become the more or less specialized 

 domain of the neuron— i.e., excitation and depression, and the ancillary meta- 

 bolic factors. Concerning the latter, let us look for a moment at the problem of 

 the physico-chemical factors responsible for drug "addiction", as well as for 

 the production of tolerance in habituated individuals and withdrawal symptoms 

 when access to the drug is terminated. It is not impossible to theorize that all 

 of these situations are directly related to initial, reversible effects of the drug on 

 the molecular orientation of specific cell membranes, associated with secondary 

 effects on ion shifts and other intracellular equilibria. Setting aside, for the 

 moment, the "psychological" factors involved in "addiction", and considering 

 this problem from a purely mechanical point of view— it could be suggested 

 that following the chronic intrusion of narcotic molecules into the neuronal 

 membranes, certain intracellular chemical changes occur which relate to "adap- 

 tation" or "tolerance." At the same time the structure of the cell (as well, 

 perhaps, as its biosynthetic mechanisms) and the membranes is altered. If, 

 subsequent to these changes in structure the drug is withdrawn, it would not 

 be at all surprising to expect a violent reaction leading to destruction of new 

 equilibria and instability of excitable structures. Addiction could be looked 

 upon as a need for alcohol or other narcotics to maintain the new steady state 

 level of the cell. Withdrawal symptoms might then be the acute result of loss of 

 the new steady state. Experiments are in progress to check some of the steps 

 in this theory. 



It has been apparent that neither decreased absorption nor increased oxida- 

 tion of alcohol seem to be the answer to the production of tolerance to it. The 

 altered response of the individual can be explained at this time only by the 

 suggestion of physico-chemical changes in certain neurons, associated with 

 their excitability cycle. This alcohol problem is closely related to that of nar- 

 cosis; indeed, the analogy between the effects of alcohol and of certain narcotics 

 is remarkable. Several fundamental considerations arise from such relation- 

 ships: 



(1) Such similarities of structure and function must reflect the involvement 

 of common biochemical and/or physico-chemical elements; and, 



(2) These common mechanisms may be divided, for purposes of investiga- 

 tion, into two sets, partially related to each other and termed inlraneuronal 

 and membranal (it must be understood that this term refers not only to the 



