Glucose and Oxygen Utilization in Sympa- 

 thetic Ganglia. I. Effects of Anesthetics. 

 II. Substrates for Oxidation at Rest and in 

 Activity 



Martin G. Larrabee and Paul Horowicz 1 



The Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, 

 Baltimore, Md. 



I. Effects of Anesthetics 



The purpose of the first part of this paper is to discuss some previously 

 published observations on the effects of anesthetics on mammalian sym- 

 pathetic ganglia, in relation to the hypothesis that the functional changes 

 in neurons caused by anesthetics are secondary to metabolic disturbances. 

 These investigations of effects of anesthetics on the synaptic system in sym- 

 pathetic ganglia were undertaken because it did not seem possible to deduce 

 with assurance the causal relationships between metabolic and functional effects 

 observed in the brain (Butler, 1950; Larrabee and Bronk, 1952). It was thought 

 that observations on a simpler neuronal system might yield helpful clues. 



Sympathetic ganglia of mammals are suitable for such studies, since (a) 

 some anesthetics have a selective action on synaptic transmission within 

 these ganglia, in the sense that transmission is blocked by considerably lower 

 concentrations than those required for block of conduction along the axons 

 leading to and from these synapses (Larrabee and Posternak, 1952), and (b) 

 some anesthetics interfere with ganglionic transmission in concentrations as 

 low as those employed to depress the central nervous system during general 

 anesthesia (Larrabee and Holaday, 1952). Thus a relatively simple preparation 

 is available which is adequately sensitive to anesthetics, contains nerve cells 

 that remain at rest until deliberately activated, and survives for many hours 

 after excision when kept at body temperature in appropriate bathing solutions. 

 Accordingly some of the difficulties encountered in interpreting experiments 



Previously published investigations cited in Section I of this paper, and some 

 observations preliminary to experiments reported in Section II, were aided by a grant 

 from the Supreme Council, Scottish Rite Masons, for research under the direction of 

 D. W. Bronk. New investigations presented in Section II were supported in part by a 

 research grant (No. B-702) from the National Institute of Neurological Diseases and 

 Blindness of the National Institutes of Health, U. S. Public Health Service. 



1 Fellow of the National Science Foundation, 1952-1955. 



84 



