Responses of chromatophores to physiological and pharmacological agents

Thesis (M.A.)--Boston Universit

Alteration of certain pharmacological effects of histamine by selected histaminase inhibitors

Thesis (Ph.D.)--Boston UniversityCompounds known to be histaminane inhibitors in vitro were studied for their ability to potentiate certain pharmacological effects of histamine. If histaminase plays a limiting role in the biological responses to histamine, histaminase inhibitors could serve as pharmacological tools in attempts to elucidate the problem of the possible physiological role of this naturally occurring and biologically highly active amine. The available information on histamine metabolism, histaminase (diamine oxidase), and histaminase inhibitors, was reviewed. The latter may be grouped into: 1) carbonyl reagents (semi-carbazides, hydroxylamines, hydrazines), and 2) substituted or unsubstituted diamines and guanidines. Recent evidence (Schayer et al. 1952, 1953) shows that aminoguanidine and other histaminase inhibitors block the major catabolic pathway of histamine in rats and, to a certain extent, in guinea pigs. Iproniazid (a hydrazine), a potent inhibitor of amine oxidase, blocks the main catabolic pathway of histamine in mice and cats. These two metabolic pathways for histamine catabolism are distinct and apparently related to different enzyme systems. In very recent reports, histaminase inhibitors are said to act as specific potentiators of histamine in the response of highly sensitive smooth muscle preparations (Arunlakshana et al. 1954; Lindel & Westling, 1954; D.J. Smith, 1953). The reported degree of potentiation is small, but it is not clear whether this is due to the same original high sensitivity of the tissue, wich may act as a limiting factor. The published results do not establish that the reported effect is related to inhibition of histaminase, since the possibility is not excluded that the compounds may act as sensitizers of histamine receptors on smooth muscle for which they appear to have some affinity (Ariens, 1954). [TRUNCATED

BMQ

BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals

Cooling and rewarming under protection of antiarrhythmic agents /

"Certain antiarrhythmic compounds previously effective in preventing ventricular fibrillation (VF) during progressive hypothermia were tested for overall protection during cooling and subsequent rewarming. Cardiac failure occurring during rewarming was completely prevented by previous rapid digitalization. Sympathomimetic amines were also effective in this respect. The phenothiazines, chlorpromazine and mepazine, and the new antiarrhythmic, amotriphene, were tested for their activity against hypothermic VF. Only chlorpromazine exhibited a significant effect, but this was not superior to that of quinidine."--Abstract."This study was performed in the Physiology Laboratory of Boston University School of Medicine. It represents an extension of an investigation into the physiology and pharmacology of the hypothermic mammalian heart initiated in 1956 under contract AF33 (616)-3805, and since August 1956 continued under contract AF33 (616)-6767 administered by the Aerospace Medical Division, Wright Air Development Division."--Foreword."October 1960."Includes bibliographical references (page 8)."Certain antiarrhythmic compounds previously effective in preventing ventricular fibrillation (VF) during progressive hypothermia were tested for overall protection during cooling and subsequent rewarming. Cardiac failure occurring during rewarming was completely prevented by previous rapid digitalization. Sympathomimetic amines were also effective in this respect. The phenothiazines, chlorpromazine and mepazine, and the new antiarrhythmic, amotriphene, were tested for their activity against hypothermic VF. Only chlorpromazine exhibited a significant effect, but this was not superior to that of quinidine."--Abstract.Report prepared by the Physiology Laboratory of Boston University School of Medicine, Boston, Massachusetts, under Contract no.Mode of access: Internet.Robert B. Sleight