The effects of the chlorides of potassium, calcium and sodium on the ? excitability of muscle

✍ Scribed by Carleton, B. H. ;Blair, H. A. ;Latchford, W. B.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1938
• Tongue: English
• Weight: 882 KB
• Volume: 12
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030120207

✦ Synopsis

It has been shown (Blair, '32, '35, '38 a ) that the a excitability gives rise to a strength-duration curve which is approximately the same as that obtained from other excitabilities and that it is evidenced by the data of latent addition (Blair, '38 a ) that the kinetics of the excitation process are essentially similar to those of other excitation processes.

It seems entirely justifiable therefore, to study the effects of salts on excitability by the a method. The advantage of doing so is that better correlations should be possible as it is quite well established by the work of Rushton ( '30, '32) that the a excitability is not concerned with nerve and therefore, is very probably the excitability of the muscle substance and more is known about the distribution of, and the effects of, salts in muscle than in nerve. The purpose of the present paper is to present a study of the effects of various concentrations of KC1, CaCl, and NaCl in Ringer's solution on the a excitability of the frog's sartorius muscle.

It has been shown by Blair ( '36, '37, '38 a ) that the strength-duration curve of frog's nerve and of frog's muscle are represented fairly well by the equation in which V is the strength of the stimulus, t its duration, R is the rheobase, and the remaining terms are constants. The term in e-"' is vanishingly small f o r all or most of the durations ordinarily used so that equation 1 reduces to

Therefore the two 'constants k and K determine, along with the rheobase R, most sets of data completely so that they express all the information obtainable from these strength-duration curves. 223 1934 VOI. 4, pp. 341-349.