C Sadavongvivad

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1. A technique for the spectrofluorometric analysis of 5-hydroxytryptamine, histamine, noradrenaline and dopamine in a single lung sample has been developed. The method is a combination of the extraction procedure of Shore & Olin (1958), plus the modification introduced by Hogans (1967) for the analysis of three of the four amines. The fourth amine,(More)
1. Eight animal species were investigated for the histamine content of the lung and can be divided into two groups: the low-level group, ranging from 2 to 7 mug/g, consisting of the mouse, rat, guinea-pig and rabbit; and the high-level group, ranging from 12 to 35 mug/g, consisting of the cat, dog, goat and human. In two species of the high-level group (cat(More)
1. The noradrenaline concentration in the lung was less than 0.5 mug/g in eight animal species.2. In the cat, dog, rabbit and goat, tyramine produced a fall in pulmonary resistance, which was reduced by the administration of either reserpine or cocaine. Although an infusion of noradrenaline increased the content of this amine in the lung of the cat,(More)
1 The interaction of pilocarpine and isoprenaline on heart rate was investigated in the spontaneously beating, right isolated atrium of the rat.2 The log dose-effect curve of isoprenaline, measured in the presence of various concentrations of pilocarpine, was not modified when the concentration of the latter did not exceed 10(-6)M even though significant(More)
The effects of acetone on contraction rate and norepinephrine (NE) release of rat right atrium were investigated. Acetone, in the concentration range 10-210 mM increased the atrial contraction rate (ACR) in a dose-dependent manner, but in concentrations exceeding 210 mM, caused a gradual reduction in the ACR from the peak. The positive chronotropic effect(More)
1 High concentrations of pilocarpine and methacholine consistently lowered the potencies of a series of adrenoceptor agonists as shown by displacement of complete cumulative dose-effect curves for their positive chronotropic action on rat isolated atria. The order of potency of the agonists was characteristic of beta-adrenoceptor activation and this was(More)