lOG 



INFLUENCE OF TEMPERATURE ON BIOLOGICAL SYSTEMS 



'active state' of Hill and hence the amount of tension developed. In 

 earlier publications, this event was called the 'alpha process' (46) and 

 it was indicated that its time course was of the order of that for the 

 contraction potential of Bishop and Kendall (45). It is the state, re- 

 sulting from depolarization, which sets the level of activation and de- 

 termines the duration of the active state. In view of the results on the 

 glycerated fiber and the heart muscle, the alpha process would be inter- 

 preted as depending on the production and disappearance of the acti- 

 vator C\i. 



the solif 

 the tota 

 arrows 



Fig. 14. Curve C: the myo- 

 gram recorded at atmospheric 

 pressure. Curve P: the myogram 

 recorded at 272 atmospheres, the 

 pressure being applied 15 sec- 

 onds before stimulation at S. 

 Curve Pi : the myogram re- 

 corded following an abrupt 

 compression at the moment of 

 stimulation and sustained 

 thereafter; the total tension at- 

 tained is indicated by the 

 broken Hne. the moment of 

 compression by the arrow p. the 

 total pressure being attained 

 within the inter\al dehmited by 

 hne in brackets following the arrow. The remaining broken lines indicate 

 1 tension attained following compressions at the moments indicated bj' the 



TIME 



DISCUSSION AND SUMMARY 



An understanding of the temperature-pressure relation in muscular 

 contraction involves the identification of discrete, measurable, contractile 

 events and an interpretation of these events in physical and chemical 

 terms. The basis for the physico-chemical approach lies, in general, in 

 the temperature-pressure relation of isolated components, such as acto- 

 myosin, enzyme systems essential to contraction and extracted muscle 

 fiber systems. In this paper an attempt has been made to present ways in 

 which the influence of temperature and pressure may be useful in re- 

 vealing important aspects of the contractile system. 



In muscular contraction the recognizable events, considered in sequence, 

 are: 1 ) the production and disappearance of an activator (Ca) with which 

 the alpha process is identified; £) the conversion of inactive actomyosin 

 to the activated contractile form; 3) the development of tension by the 

 activated unit. 



