M. Holzbauer, M. Vogt
May 1, 1956
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Influential Citations
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Journal
Journal of Neurochemistry
Abstract
THE observation that reserpine causes a 'severe loss of 5-hydroxytryptamine from brain tissue (PLETSCHER, SHORE, and BRODIE, 1956; PAASONEN and VOGT, 1956) prompted the investigation of the effect of this drug on the noradrenaline content of brain. The region analysed was the hypothalamus, as its noradrenaline content is high and as the effect of reserpine on the 5-hydroxytryptamine of brain had been demonstrated on this region (PAASONEN and VOGT, 1956). Cats were used in which the left adrenal gland had been denervated in an aseptic operation under ether between twelve and twenty days before the experiment. This procedure allowed simultaneous observation of the noradrenaline content of the hypothalamus and of any central stimulation of the sympathetic system produced by the drug; such stimulation would appear as a difference in the amount of medullary amines (adrenaline and noradrenaline) found in the innervated and the denervated gland. The methods used have all been reported (VOGT, 1954) with the exception of the use of pithed rats (SHIPLEY and TILDEN. 1947) for some of the assays of noradrenaline and adrenaline; this preparation gives a steadier baseline than the anaesthetized rat treated with hexamethonium. Control experiments showed that small doses of reserpine, such as might be present in the brain extracts, did not interfere with the assays. The reserpine (Serpasil Ciba, ampoules of 2.5 mg/ml) was given i.p., and doses of the drug and duration of the experiments are shown in Table 1. They were the same as those found to release most of the 5-hydroxytryptamine from the hypothalamus of the dog. The results are presented in Table 1. Cats 1-3 belonged to a litter aged 44 months, cats 4 8 to a second litter of 14 months. Motility and posture were more seriously affected in the young than i n the adult mimals. The figures for the noradrenaline content of the hypothalamus are recorded in column 6: in column 7 they are expressed as percentages o f a mean of 1.4 pg/g fresh tissue (range 0.90-2.08 pg) obtained previously for twenty normal cats of all ages. Column 8 expresses the findings in litter 2 as percentages of the noradrenaline concentration found in cat 8, an uninjected control of the same litter. These figures are probably more reliable than those of column 7, as the variation within litters has previously been found to be small (VOGT, 1954). Irrespective of which calculation is chosen, the results leave no doubt that the injection of reserpine caused a loss in hypothalamic noradrenaline; the loss was very severe in the young kittens, less so in the adult animals. It was at least as great as that produced by large doses of morphine (VOGT, 1954). The effect of reserpine on the adrenal glands appears, howeker, to differ from that of morphine. After morphine.