Chinese Journal of Physiology

96 T. KING anp C. PAK

along the lines of our earlier work with ephedrine (3), their comparative effects upon the nasal mucous membranes.*

METHOD

Dogs anesthetized with luminal (0.18 gm per kg) were used throughout the experiments. The modified nasal plethysmographic method of Tschalussow, described in our previous paper (3) was employed to determine the volume change of the nasal cavity. A fall in the tracing denoted an increased nasal volume resulting from shrinkage of the nasal mucous membrane. The blood pressure was recorded from the left carotid artery. The drugs (1 cc of the solution and 2 cc saline) were injected into the femoral vein.

A preliminary trial was made of the effect of repeated dosage of the drug. It is well-known that successive doses do not produce the same effect on blood pressure on account of increasing depression of the heart muscle. It is not known whether the neurotropic effect upon the nose can be repeatedly demonstrated without similar decreases.

In the comparative experiments the relative maximal effects of only two drugs were determined by three injections. The third injection was considered merely a contro] of the first one. Although its effect was not quantitatively identical with the first injection, its action was similar to it, and did not resemble the second injection made with the isomer to be compared. An interval of three hours was allowed between each of the injections. The average dosage was about 0.2 mg per kg of body weight. In estimating the relative dimensions of the nasal volume following injection of the drug, measurements were made on the perpendicular line drawn between the initial level and the lowest level of the curve produced. Because the nasal volume has been proved to be extremely sensitive to vasoconstrictor drugs, as observed by Moltschanow (4) who employed the changes in nasal volume for the bioassay of adrenalin and found that dilutions as high as 310° when injected directly through the carotid could repeatedly produce a considerable increase in the nasal volume, we tried to produce the same result with ephedrine by injection through a cannula attached to the carotid artery. A noticeable increase of the nasal volume was successfully obtained with ephedrine 1 x 10 but the responses of the nasal

*Since presenting this paper Chen has published work showing the effect of ephetonin on nasal volume, and he quotes Slack as being “unable to detect any significant difference between their constricting power’’. Chen, K.K., J. Pharm. Exper, Therap., 1928, 33, 237-258.