THE COMPARATIVE PHYSIOLOGICAL ACTION OF SOME DERIVATIVES OF GUANIDINE

¹ From the Gates Chemical Laboratory, California Institute of Technology, Pasadena, California

In general the blood pressure response to guanidine, its alkyl, acetyl and amino derivatives consists of a fall in the blood pressure followed by a rise that may be quite prolonged. The intensity of the effect of these derivatives is different, the acetyl, methyl, dimethyl, ethyl and ethanol derivatives being considerably more marked than the amino derivative or guanidine itself. The heart rate and amplitude of the heart beat are affected quite considerably by some of these derivatives, the effect being most marked with the ethyl and dimethyl derivatives. Methyl, ethanol, acetyl and aminoguanidine have a less marked effect on the heart rate and amplitude of the heart beat, while guanidine itself has no appreciable effect.

The arylguanidines, symmetric diphenylguanidine and triphenylguanidine, are active with small doses. They cause a fall in blood pressure with a decrease in heart rate. The heart rate is very markedly affected with the diphenyl derivative, while the triphenyl derivative is not as active in this respect.

The respiratory effect of the different guanidine derivatives is most marked with acetylguanidine. Methyl, dimethyl, ethyl, ethanol and aminoguanidines all have considerable effect on both the respiratory rate and amplitude while the aryl derivatives used and guanidine itself are not marked in their action. The respiratory response consists of a short period of decreased amplitude followed by a longer period of increased respiratory rate.