Volume 31, Issue 6
June 1950, pages 287-356
pp 287-301 June 1950 Obituary Note
pp 302-307 June 1950
pp 308-330 June 1950
pp 331-338 June 1950
pp 339-350 June 1950
pp 351-356 June 1950
Frog ’s and dog ’s stomach show the predominance of alactic tone in the pyloric regeion and lactic tone in the cardiac region.
The tone in the pyloric region has the properties of the asphyxial contraction.
The tension due to tonic contraction of the pyloric muscle can be destroyed without affecting the twitch contraction suggesting that these two are mediated by different contractile mechanisms.
Stretching of muscle antagonises elongation produced by distilled water and other substances.
The muscle from the pyloric and cardiac regions behave differently in distilled water. The former contracts and the latter relaxes. These reactions are produced both in living as well as dead muscles, so it is concluded that unstriated muscle contains two kinds of contractile proteins for lactic and alactic tones respectively.
Stretching increases the tendency to contraction and decreases that to inhibition. Asphyxia also produces similar effects.
When increased demand is made on unstriated muscle with normal oxygen supply or normal demand with diminished oxygen supply, it puts into action a contractile mechanism which does not require energy.