reasons why reserpine does not exert sedative activity when room temperature is 37? or 0?C. We believe that the stress reaction with release of catecholamines takes place at 0? and at 37?C. In this regard recent experiments may be recalled in which DOPA, a precursor of noradrenaline, antagonizes the sedative activity of reserpine (13). The increase of brain serotonin at 37?C may be considered as a situation analogous to that occurring after iproniazid administration, when reserpine does not

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... sedation (14). Note added in proof. Since this communication was submitted for publication we checked our results with a more specific method for evaluation of brain serotonin [D. F. Bogdanski et al., J. Pharmacol. Exptl. Therap. 117, 82 (1956)]. Thus, using a spectrofluorimetrical technique, we confirmed that reserpinized rats kept at a room temperature of 37?C have a higher brain serotonin (0.36 ?+ 0.009 kRg) than the animals treated with reserpine at a room temperature of 22?C (0.16?+ 0.008 ktg). References and Notes 1. There is also some disagreement [C. Bianchi, Nature 179, 202 (1957); M. Taeschler and A. Cerletti, J. Pharmacol. Exptl. Therap. 120, 179 (1957)] and some evidence of the importance of catecholamine release after administration of reserpine [A. Carlsson, in Psychotropic Drugs (Elsevier, Amsterdam, 1957), p. 363; and A. Carlsson, M. Lindquist, T. Magnusson, Nature 180, 1200 (1957)], but this is not the objective of this report. 2. B. B. Brodie, P. A. Shore, A. Pletscher, Science 123, 992 (1956). 3. E. Costa stressed recently the increase of serotonin activity in certain smooth-muscle preparations in the presence of LSD [Proc. Soc. Exptl. Biol. Med. 91, 39 (1956)]. 4. B. B. Brodie and P. A. Shore, Ann. N.Y. Acad. Sci. 66, 631 (1957). 5. A. Pletscher, Helv. Physiol. et Pharmacol.