53 cross the blood-brain barrier with ease.19 they can release and/or replace the classical neurotransmitters, and they mimic the stereotypies of amphetamine. 20 They have variously been shown, or claimed, to be excreted abnormally in the urine of patients with migraine, 21 parkinsonism,2aschizophrenia,23 and depression.24 They are all synthesised in one way or another from the essential aminoacids, phenylalanine and Further study of these interesting " new " tryptophan. " micro " amines at the fundamental as well as the clinical level seems to be justified.
pharmacological agents, they
Psychiatric Research Unit, University Hospital, Saskatoon, Saskatchewan, S7N 0W8, Canada.
ALAN A. BOULTON.
THYROTROPHIN-RELEASING HORMONE IN DEPRESSION SIR,-Iread with great interest the article by Dr Mountjoy and his colleagues (May 18, p. 958). Four years ago I was interested in how electroconvulsion therapy (E.c.T., might be effective in depression, and first conducted
investigations measuring T4, free T4, and thyroid-stimulating hormone (T.S.H.) before, during, and after courses oi E.c.T. in 14 patients with negative results, although the discovery of what could be termed 25 " subclinical myxredema" in 2 patients was interesting. However, subsequent detailed study of 4 depressed patients with samples immediately before E.c.T. and at 15, 30, 45, and 60 minutes did show a very small rise in all 4 patients:
within the normal
Normal range 8-20 µ units per ml. for T.S.H. All samples estimated in duplicate. Standard 68/38.
Later I found a patient with depression and impotence who failed to respond to 200 µg. of intravenous T.R.H. and whose resting levels of T.S.H. were subnormal. When the depression had improved, a low normal T.S.H. level (7-8 µU per ml.) was found, and further T.R.H. testing results are awaited:
endocrinological approach to some cases of depression discouraged by what appears to have been a negative study. Ormston et al.26 (cited by Dr Mountjoy and his colleagues) very definite rise in T.s.H. after oral doses of of 5 mg., and significant changes of other measures of thyroid function, such as protein-bound iodine, with the oral dose of 40 mg. used in the trial. No change in either of these indices was found by Mountjoy et al.
T.R.H. in excess
There are therefore four explanations: (1) the timing of the specimens was inappropriate (stated as " serial "); (2) the patients did not take the tablets (efforts to check this were carefully recorded by the authors); (3) the tablets were inactive; or (4) in the population studied (e.g., depressed patients), the hypothalamic-pituitary axis is abnormal and the usual response to T.R.H. is absent. Other reports cited by Mountjoy et al. have demonstrated this last possibility, and I mention a further isolated case. If a controlled trial can properly establish such an organic abnormality of pituitary and/or hypothalamic function in depressed patients, the therapeutic implications may be considerable. In such a situation, if an agent such as T.R.H. were to be expected to help a much larger dose than usual might be necessary. Wharfedale General Hospital, Otley, Yorkshire.
W. N. HUTTON.
UPPER GASTROINTESTINAL ENDOSCOPY SIR,—Despite an earlier report,27 it is still widely believed that upper gastrointestinal endoscopy is less acceptable to the patient than a barium meal. After 30-45 mg. nordiazepam orally one hour before endoscopy as premedication, followed by an amethocaine lozenge to produce oral anaesthesia, sufficient diazepam was given intravenously to produce ptosis or dysarthria. 100 consecutive patients were asked to compare their experiences after œsophagogastroduodenoscopy with a barium meal, 50 by postal questionnaire and 50 by direct inquiry. The results were: Preferred
Only 22 patients thought that the procedure was unpleasant, but 52 patients complained of a sore throat afterwards. None remarked of other side-effects, although a small number were affected by the diazepam for the rest of the day. Endoscopy is highly acceptable and should be used more readily, especially in emergency situations such as acute gastrointestinal bleeding, when successful identification of the bleeding site is much more likely than by radiology.28 Department of Medicine, Llandough Hospital, Penarth, Glamorgan.
P. M. SMITH.
SIR,—Dr Steer’s attack (June 1, p. 1107) on the use of units is unjustified. In 1960 the General Conference of Weights and Measures adopted the S.l. system (Systeme
d’Unites) with the following basic units: kilogramme, second, ampere, Kelvin, and candela (and, later, mole). Prefixes are used to express multiples and fractions of these units. These prefixes range from Tera (T) (1012) to atto (a) (10-18). By combination of the various basic units the other supplementary units can be derived (e.g., watt, newton). Internationale
give these results because
I would not like to
19. Oldendorf, W. H. Am. J. Physiol. 1971, 221, 1629. 20. Faurbye, A. Comp. Psychiat. 1968, 9, 155. 21. Nature, 1969, 222, 521. 22. Boulton, A. A., Marjerrison, G. L. ibid. 1972, 236, 76. 23. Boulton, A. A., Marjerrison, G. L., Majer, J. R. J. Med. Acad. Sci U.S.S.R. 1971, 5, 68. 24. Fischer, E., Spatz, H., Heller, B., Reggiani, H. Experientia, 1972 28, 307. 25. Evered, D. C., Ormston, B. J., Smith, P. A., Hall, R., Bird, J. Br med. J. 1971, ii, 199.
26. Ormston, B. J., Kilborn, J. R., Garry, R., Amos, J., Hall, R. ibid. 1973, i, 657. 27. Brown, P., Salmon, P. R., Read, A. E. Lancet, 1972, i, 270. 28. Cotton, P. B., Rosenberg, M. T., Waldram, R. P. L., Axon, A. T. R. Br. med. J. 1973, ii, 505.