Delayed heat production of caffeinized frog muscles

✍ Scribed by Saslow, George

• Publisher: Wiley (John Wiley & Sons)
• Year: 1936
• Tongue: English
• Weight: 575 KB
• Volume: 8
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030080109

✦ Synopsis

The heat production of muscles treated with caffeine appears to have received little attention except for the observations of Hartree and Hill ('24)' which dealt with concentrations between 0.05 and 0.07 per cent. Their experiments were concerned chiefly with the long-continued heat production consequent upon a stimulus and the spontaneous long-continued heat production of caff einized frog sartorii. From the value of the heat production over several hours a) in oxygen and b) in nitrogen, the ratio of total aerobic to total anaerobic heat was determined.

I n the present experiments the ratio total to initial heat has been determined directly for single twitches and short tetani in muscles treated with concentrations of caffeine which do not lead either spontaneously or after stimulation to the long-continued heat production investigated by Hartree and Hill. The observations indicate that the delayed heat is markedly reduced below the normal after a response. This result, at first sight surprising in view of the high figures obtained by Hartree and Hill's indirect method and of the known high oxygen consumption of these muscles (Fenn, '31)' may perhaps be explicable in terms of present knowledge of the chemical changes occurring in active muscle, as is suggested below.