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IV.—The Pharmacological Action of Harmine. By James A. Gunn, M.A., M.D., 
D.Sc. (From the Pharmacology Laboratory of the University of Edinburgh.) 
(MS received March 20,1911. Read same date. Issued separately August 9, 1911.) 
CONTENTS. 
PAGE PAGE 
Introductory : : ; : 0 : : 83 EK. Action on the Cirenlakion=. 
(a) Heart . F ; : : : : 88 
A. Lethality of Harmine . : : : : 84 (b) Blood-vessels . L 91 
B. Symptoms produced by Hee (c) Heart and Blood-vessels (Blood Beeure) 91 
(a) in Frogs. 6 : : : : 85 F. Action on Respiration . : c : : 94 
(6) in Rabbits. ; ; : : : 86 G. Action on Temperature . : ; : : 94 
C. Action on the Central Nervous System— H. Action on the Uterus. : d ‘ : 95 
2 : ; : : Bi General Summary : : : : : 95 
(6) Mammals and Seen : : : : 87 ' 4 , 
Comparison of the Actions of Harmine and 
D. Action on Skeletal Muscle . ‘ : ‘ 88 Harmaline c : : : : : 96 
INTRODUCTORY. 
The seeds of Peganwm Harmala contain two alkaloids, Harmaline and Harmine. 
The pharmacological actions of the former alkaloid have been described in a previous 
communication to this Society ;* in this paper an account is given of the pharmacology 
of the second alkaloid, Harmine. 
Harmine (C,;H;.N,O) was discovered by FritcHE in 1847. Apart from a few 
observations by TaPPEINER, its pharmacology has not been investigated. TapPEINER t 
states that, in mammals at least, the general nature of poisoning by harmine is qualita- 
tively the same as by harmaline, but that the former alkaloid is weaker in action. He 
found that a dose of 0°2 gramme per kilo of harmine is fatal to the guinea-pig in about 
12 hours, while the same dose is fatal to the rabbit in about 1 hour, and that a frog is 
killed in about 7 hours by a dose of 0:03 gramme (per kilo?). He states further that 
there appears to be one qualitative difference between the actions of the two alkaloids, 
in that harmine produces paralysis of reflex excitability before arrest of the heart. It 
may be stated here that this does not constitute a qualitative difference between the 
actions of harmaline and harmine, because the same effect is produced by harmaline. 
My investigation of harmaline having shown that the actions of this alkaloid 
very intimately resemble those of quinine, a more extended investigation seemed 
* Gunn, Trans. Roy. Soc. Edin., xlvii., 1909, pp. 245-272, 
+ TapprEiner, Archiv fiir exper. Pathol. uv. Pharmakologie, Bd. xxxv., 1895, p. 69. 
TRANS, ROY. SOC. EDIN., VOL, XLYIII, PART I. (NO. 4). 13 
