THE ACTION OF BENZODIOXANE IN MAN AN EXPERIMENTAL INVESTIGATION

759 a review of reported cases it appears that cases et al. (1949) extracted noradrenaline from cases of megaloblastic anaemias of pregnancy and refractory adrenal medullary tumour, and it therefore seemed that cases of megaloblastic anaemia with free gastric hydro- - noradrenaline rather than adrenaline might perhaps be chloric acid have not been generally investigated for the cause of the hypertension in this condition. Hence it became necessary to investigate the effect of dioxane the presence of idiopathic steatorrhcea. 933F on noradrenaline hypertension, which consists of is to R. due Dr. for Kempthorne perAcknowledgment a rise in systolic and diastolic pressures due to increased mission to investigate case 2, and to Glaxo Laboratories Ltd. peripheral resistance (Goldenberg et al. 1948) and is for-supplies of vitamin B,2. very similar to that seen in paroxysmal hypertension REFERENCES due to pheeochromocytoma. The experiments described here were planned to Bethell, F. H., Myers, M. C., Neligh, R. B. (1948) J. Lab. clin. Med. 33, 1477. contrast the effect of the dioxane on hypertension proCallender. S. T. E. (1944) Quart. J. Med. 13, 75. duced by adrenaline in normal subjects with. that produced Cartwright, G. E., Wintrobe, M. M. (1949) Annu. Rev. Physiol. 11, 335. noradrenaline, and to observe the resultant circulatory by Cooke, W. T., Elkes, J. J., Frazer, A. C., Parkes, J., Peeney, changes by measuring the flow of blood in the calf and A. L. P., Sammons, H. G., Thomas, G. (1946) Quart. J. Med. 15, 141. the hand by venous-occlusion plethysmography. One Davidson, L. S. P., Davis, L. J., Innes, J. (1942) Brit. med. J. ii, 31. might expect to find, perhaps, a vasodilatation in muscle Girdwood, R. H., Clark, J. R. (1948) Ibid. i, 819. Day, L. A., Hall, B. E., Pease, G. L. (1949) Proc. Mayo Clin. 24, 149. or skin accompanying the fall in blood-pressure. Fourman, L. P. R., Higgins, G., Quelch, P., O’Brien, J. R. P.,

From

of

.

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Witts, L. J. (1948) Clin. Sci. 7. 121. Fullerton, H. W. (1943) Brit. med. J. i, 158. Israëls, M. C. G. (1939) J. Path. Bact. 49, 231. Nielsen, O. P. (1941) Acta med. scand. 108, 421. Ritter, J. A., Crocker, W. J. (1939) Amer. J. Obstet. Gynec. 38, 239. Spies, T. D., Suarez, R. M., Garcia Lopez, G., Milanes, F., Stone, R. E., Lopez Toca, R., Aramburu, T., Kartus, S. (1949) J. Amer. med. Ass. 139, 521. Ungley, C. C. (1938) Lancet, i, 925. (1949) Brit. med. J. ii, 646. (1950) Lancet, Feb. 25, p. 353. -

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THE ACTION OF BENZODIOXANE IN MAN AN EXPERIMENTAL INVESTIGATION

F. T. G. PRUNTY

H. J. C. SWAN

M.D. Camb., M.R.C.P.

M.B. Lond., M.R.C.P.

READER

IN

CHEMICAL

LECTURER

PATHOLOGY AND PHYSICIAN TO ST. THOMAS’S HOSPITAL,

ST.

LONDON

With

a

IN

PHYSIOLOGY AT

THOMAS’S

HOSPITAL

MEDICAL SCHOOL

note on

negative benzodioxane

test

G. M. WILSON

M.B., B.Sc. Edin., F.R.C.P.E., M.R.C.P. MEDICAL UNIT, ST. MARY’S HOSPITAL MEDICAL SCHOOL, LONDON

ASSISTANT,

IN 1947 Goldenberg et al. described a test for hypertension due to circulating adrenaline, based on the reversal of the adrenaline pressor effect by the adrenolytic benzodioxanes (Fourneau and Bovet 1933). They found that the intravenous injection of ’933F,’ 2-(I-piperidylmethyl)-1 : 4-benzodioxane, abolished or significantly decreased the pressor effect observed during infusions of adrenaline in normal subjects. The blood-pressure usually returned to the " pre-dioxane " level in 10-15 minutes. This effect was also found in patients with phseochromocytoma and hypertension. However, the blood-pressure rose when 933F was given to patients with so-called essential hypertension. These opposite responses differentiate the rare phseochromocytoma from the common essential hypertension, and the intravenous injection of 933F has been applied as a clinical test for phaeochromocytoma by Goldenberg and his colleagues and by Cahill (1948). Dana and Calkins (1949) report two " positive reactions "-i.e., a fall in blood-pressurein 67 patients with sustained hypertension. One of these positive reactions was obtained in a patient with phooochromocytoma, but the other occurred in a patient with a neuroblastoma of the adrenal gland, and this was considered to be a false positive. From our experience with intravenous infusions of adrenaline it appeared to us, as it had to Goldenberg and Aranow (1949), that their pressor effect was not comparable with the hypertension resulting from phseochromocytoma. We found it unusual for circulating adrenaline to raise the diastolic pressure, much less to raise it to levels commonly seen in paroxysmal hypertension due to adrenal tumours. Holton (1949) and Goldenberg

EXPERIMENTAL

The

between the ages of 22-45 and far as is known, normal in every respect. They came to the laboratory and rested for an hour before any experimental procedure was undertaken. An air-filled plethysmograph was then applied to. the right calf and another to the right hand. A sphygmomanometer were,

subjects

were men

so

cuff was fitted to the left forearm. A 16-gauge needle was inserted into a vein in the right forearm, and an infusion of physiological saline was started throughPolythene ’ tubing sealed to the needle. The capacity of the tubing was about 1-5 ml. Basal estimations of blood-pressure, pulse-rate, and blood-flow in hand and calf were then made while the saline infusion was running. When reasonable stability had been achieved, the required drug (adrenaline or noradrenaline) was continuously infused through the same tubing and needle. The concentration required was delivered in 4 ml. of saline solution per minute. After 20 minutes, by which time the circulatory effects were usually reasonably stable, 933F . 0-25 mg. per kg. of body-weight was administered. In 5 oases the injection was made into a small rubber tube interposed between the syringe and the polythene tubing. In 2 cases (subjects 1 and 6) the injection was made directly into another vein in the same arm. The injection was made slowly, being completed in 2 minutes. The changes in blood-pressure and pulse-rate were observed at 1/a-minute intervals, and the changes in limb blood-flow were estimated at 1/4 -minute intervals for the next few minutes. Observations were then made at minute intervals for about 15 minutes, after which the infusion of adrenaline or noradrena)ine was stopped. We are indebted to Mr. A. J. Ewins, D.SC., F.R.s., of May & Baker Ltd., for the supply of 933F and for investigating its properties after sterilisation by various methods. He reports that the batch from which our sample was supplied fulfilled the known properties of 933F. Autoclaving at 120°C for half an hour neither caused chemical changes in the compound nor affected its spasmolytic properties. RESULTS

OF

RECEIVING

*

INJECTING

INFUSIONS

Noradrenaline

infusion

933F

OF

INTRAVENOUSLY IN PERSONS OR NORADRENALINE

ADRENALINE

discontinued

injection.

just

after

the

dioxane

760 RESULTS were carried out : 4 on subjects adrenaline infusions and 3 on subjects noradrenaline infusions. The results are shown in the accompanying table. It was intended to extend the series further, 1) tit for reasons described below this was not done.

In

all,

7

experiments

undergoing undergoing

Adrenaline

Subject I.-Aged 45. An infusion of 0-03 mg. of adrenaline per minute was needed to raise the systolic blood-pressure 20 mm. Hg. Administration of the dioxane caused a transient fall in systolic pressure, a well-marked tachycardia, and a rise in systolic pressure within 3 minutes of its injection. Thereafter the systolic and diastolic pressures continued to rise gradually until the adrenaline infusion was stopped. The tachycardia abated within 5 minutes but did not settle to the pre-dioxane level until the adrenaline infusion had been discontinued. The subject noticed a -flushing of the face and upper chest with a feeling of great heat some 40 seconds after the start of the dioxane injection. He also developed a tremor of his right hand and complained of apprehension. Subject 2.-Aged 23. changes are shown in fig. symptoms.

The recorded 1. There were

haemodynamic no

untoward

Noradrenaline

Subject 5.-Aged 23. An infusion of 0-02 mg. of noradrenaline per minute raised the diastolic pressure 15 mm. Hg and the systolic pressure 20 mm. Hg. Administration of the dioxane caused a transient fall in diastolic pressure, with a subsequent rise in systolic pressure to 10 mm. Hg above the

Fig. 2-Blood-pressure, heart-rate, and blood-flow in hand and calf in subject 5, receiving an infusion of noradrenaline. The figure gives the concentration of noradrenaline per minute. At the arrow 14 meof 933F was injected in the manner described.

noradrenaline level. The bradycardia was abolished, and there was a transient increase in blood-flow in the hand and calf. The major hsemodynamic changes are shown in fig. 2. There was little symptomatic discomfort.

Subject 6.-Aged 27. An infusion of 0-02 mg. of noradrenaline per minute produced a rise in systolic and diastolic pressures which was considered excessive, so the infusion-rate was reduced to 0-01 mg. per minute, which produced an increment of 15 mm. Hg diastolic and 30 mm. Hg systolic. ’There was the usual bradycardia with a decrease in bloodflow in the calf. When readings had been stabilised benzodioxane was injected slowly, and within 40 seconds the subject noted an unpleasant sensation of warmth on the chest and spreading up into the face ; 30 seconds later he appeared to be very distraught (afterwards he said he had felt he was losing consciousness) and started violent involuntary movements with his legs. The injection of dioxane, then about two-thirds complete, was discontinued and the noradrenaline infusion shut off. The subject continued to move his legs for several minutes. Within 30 seconds of the start of the dioxane administration a pulse-rate of 140 per minute was recorded with a fall of diastolic pressure from 100 to 75 mm. Hg and a rise in systolic pressure from 185 to 200 mm. Hg. Owing to the movements of the subject the records of bloodflow in calf and hand at the time were useless. The hypertension- persisted for an hour or more after the dioxane had been injected, and the pulse-rate remained between 80 and 90 per minute for that time.

j and blood-flow in hand and calf in infusion of adrenaline. At the point indicated a solution of adrenaline in saline was substituted for the saline infusion. This solution gave a concentration of 0.0 mg. of adrenaline per minute, later increased to 0-02 mg. per minute. At the arrow IS mg. of 933F was injected slowly, as described in the text.

Further investigations were made on patients without cardiovascular abnormality, and it was found that, in the absence of circulating adrenaline or noradrenaline, the injection of 933F in comparable doses produced little if any change in pulse-rate or blood-pressure.

Fig. I-Blood-pressure, heart-rate, subject 2, receiving

an

DISCUSSION

The probable sequence of injection during adrenaline

events following the dioxane noradrenaline infusions is

or

.

761 follows. There is an initial peripheral vasodilatation, shown in skin and muscle by an increase in blood-flow in calf and hand, causing a slight fall in diastolic pressure. Associated with this change there is a tachycardia which may be responsible for a definite increase in cardiac output, restoring the blood-pressure to a level equal to or above that before its administration, despite a continued increased blood-flow in the muscles. We have no direct estimate of the cardiac output, but from the other changes recorded it seems reasonable to assume that cardiac output is increased. Thus it appears that the injection of the dioxane 933F during an adrenaline infusion in man causes a pronounced vasodilatation, but the subsequent increase in the output of the heart per minute may lead to a further rise in arterial blood-pressure, as seen in our subjects. In their original paper Goldenberg et al. (1947) investigated this problem in a similar way on a large series of normal people undergoing adrenaline infusions and found that 933F produced a fall in blood-pressure in these circumstances. Moreover, Dr. Goldenberg (personal communication) has recently told us that he has effected a fall in blood-pressure in 12 subjects undergoing infusions of noradrenaline by the injection of 933F. This fall is neither so great nor so sustained as that observed during adrenaline infusions. Therefore there is a considerable weight of experimental evidence to support Goldenberg’s contention that 933F can be used to differentiate phseochromocytoma with hypertension from hypertension due to other causes. In our recent series of normal subjects, however, we did not observe a sustained fall in blood-pressure in any case. Moreover, 5 of the 7 subjects reported distinctly unpleasant symptoms, and subject 6 had a severe reaction to the 933F. The matter has therefore not been pursued so fully as was intended and our series is small. Nevertheless the results are reported as factual observations, however unexpected. In the clinical application of this test, as previously mentioned, considerable evidence of its positive value has been reported by Goldenberg (personal communication) and by Cahill (1948). However, Dr. G. M. Wilson, in an addendum to this paper, describes briefly a case of proved phseochromocytoma in which the reaction to 933F was the same as in our subjects. A "false positive " has also been reported by Dana and Calkins as

(1949).

.

The experimental findings in animals are of limited value in assessing the application of such a test to man, but in the chloralosed vagotomised dog Hermann et al. (1939) showed that infusions of adrenaline after the administration of a large dose of 933F produced a result very similar to that which we observed. On the other hand, Melville (1937) found that, in dogs, 933F reversed the adrenaline pressor effect. It will be seen that, though there is good evidence of the value of 933F in the diagnosis of phseochromocytoma, there are still some discrepancies in the observed results. How can these be explained1 The blood-pressure level is a complex end-response, in so far as it is a product of the cardiac output and the total peripheral resistance. In our subjects we feel that a probable increase in cardiac output more than balanced a pronounced vasodilatation, while in others the reverse may have held good. Further investigation on these points is needed.

Fig. 3-Rise in systolic pressure, with little change in diastolic pressure when 933Fwas injected in a patient with a phaeochromocytoma of the adrenal gland.

Both the fall in were

the skin and skeletal muscles. Unpleasant and alarming

Benzodioxane (933F) 7 normal

injected intravenously into subjects undergoing infusions of adrenaline or was

noradrenaline. A fall in blood-pressure lasting a few seconds was succeeded by a rise to a level above that observed before the dioxane was injected.

symptoms

were

at times

produced. The significance

of these findings, with particular reference to the use of the dioxane effect in the diagnosis of phaeochromocytoma, is discussed in relation to the findings of other workers. ADDENDUM

.

Two further experiments have been performed using ’Benodaine’ brand of 933F (for which we are indebted to Dr. R. C. Pogge of Messrs. Merck & Co., New Jersey). Given during an infusion of adrenaline, benodaine produced an effect in all respects similar to those described above, whereas during an infusion of noradrenaline a fall of systolic pressure of 5-10 mm. Hg occurred during a period of 20 minutes when the infusion was terminated.

Negative Benzodioxane Test (DR. G. M. WILSON) A man, aged 38, was admitted to St. Mary’s Hospital, under Prof. G. W. Pickering, with 2 years’ history of recurrent attacks of pallor, trembling, and sweating. A mass felt below the right costal margin was shown radiologically to be a tumour of the adrenal gland. The blood-pressure was Note

on

constantly elevated at about 180/120 mm. Hg. The patient was given an intravenous drip-saline infusion, and his blood-pressure was recorded. After 46 minutes, 15 mg. of 933F (May & Baker) was injected into the tubing, without the patient’s knowledge, over a period of 2 minutes. The injection produced a considerable rise in systolic pressure with little change in diastolic pressure (fig. 3), and conspicuous flushing of the face. Subsequently a phseochromooytoma, weighing 45 g. and 5 em. in diameter, was removed from the patient’s right adrenal gland. He has had no further paroxysmal attacks over a period of 15 months, but his arterial pressure has remained elevated.

Full details of this and two other cases of phmochrome tumours of the adrenal gland are to be published later. REFERENCES

Cahill, G. F. (1948) J. Amer. med. Ass. 138, 180. Dana, G. W., Calkins, E. (1949) Bull. Johns Hopk. Hosp. 84, 283. Fourneau, E., Bovet, D. (1933) Arch. int. Pharmacodyn. 46, 178. Goldenberg, M., Aranow, H. (1949) communication to American Heart Association, June 3. Faber, M., Alston, E. J., Chargaff, E. C. (1949) Science, 109, 534. Pines, K. L., Baldwin, E. de F., Green, D., Roh, C. (1948) Amer. J. Med. 5, 792. Snyder, C. H., Aranow, H. jun. (1947) J. Amer. med. Ass. 135, 971. Hermann, H., Jourdan, F., Morin, G., Vial, J. (1939) C.R. Soc. Biol. Paris, 131, 282. Holton, P. (1949) J. Physiol. 108, 525. Melville, K. T. (1937) J. Pharmacol. 59, 317. -

SUMMARY

blood-pressure and its subsequent rise accompanied by tachycardia and vasodilatation in

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