78 ROLAND FISCHER 



of biological activity than those with low affinity for wool. This would be in 

 agreement with the observation that there are many substances each of which 

 acts on more than one enzyme. Ergotamine, e.g. inhibits monoaminoxydase, 

 diaminoxydase and cholinesterase. 



Let me conclude with a quotation from Zupancic (1953): "The overlapping 

 sensitivity of a few enzymes toward the same substance would be analogous to 

 the retinal cone pigments with their overlapping but quantitatively different, 

 absorption of the same monochromatic light." 



Summary 



Wool is used as an in vitro model of the proteinous surface of nervous re- 

 ceptors (enzymes) in vivo. 



Affinity for wool appears to be among the characteristics of compounds acting 

 on enzymes which are essential to maintain membrane polarization at rest and 

 recovery after transmission. 



Certain compounds, apparently those acting by competitive inhibition, are 

 more firmly bound to wool (i.e. they display high affinity) than the compounds 

 they displace. 



The limitations of the wool-model are discussed and speculations forwarded 

 to account for the overlapping sensitivity of a few enzymes toward the same 

 substance. 



Acknowledgments 



I am indebted to Dr. Paul Larose, Head, Fibre Laboratory, Division of Pure 

 Chemistry, National Research Laboratories, Ottawa, and to Dr. A. Hoffer, 

 Chairman, Saskatchewan Committee on Schizophrenia Research, for their 

 stimulating discussions and valuable advice. 



The compounds used in these studies were generously supplied by the follow- 

 ing pharmaceutical companies: Abbott Laboratories, Ciba, Geigy, Hoffman- 

 LaRoche, McNeill Laboratories, Parke Davis, Poulenc, Sandoz, Smith, Kline 

 and French, Squibb, Upjohn, and Winthrop-Stearns. Figures and photographs 

 are the work of Mr. Harry Wood, Regina. 



These studies were supported by the Department of National Health and 

 Welfare, Ottawa, Canada. 



References 



Bailey, P. 1950. Considerations sur l'organisation et les fonctions du cortex cerebral. 



Rev. Neurol. 82: 3-20. 

 Behringer, K. 1927. Der Mezkalinrausch. Springer. Berlin. 

 Bergmann, F. and A. Shimoni. 1953. The changes in the nerve membrane and the 



role of cholinesterase in the conductive process. Biochim. et Biophys. Acta. 10: 



49-54. 



