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Die sintese en farmakodinamika van ringgehalogeneerde fenieletielamienderivate

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dc.contributor.advisor Venter DP, Prof en
dc.contributor.author Brink CB en
dc.date.accessioned 2016-09-22T07:18:08Z
dc.date.available 2016-09-22T07:18:08Z
dc.date.submitted 1991 en
dc.identifier.uri http://hdl.handle.net/20.500.11892/12368
dc.description.abstract In this study an investigation was done on the general pharmacodynamics and possible intrinsic activity on &alpha;-adrenergic receptors of ring halogenated phenylethanolamine derivatives. Pharmacodynamic studies done on o-chloroprenaline and dichloroprenaline and which are described in the literature, strongly suggest that these compounds respectively are an agonist and competitive antagonist on the &Beta;-adrenergic receptors. Questions arose concerning the influence of ring halogens on the intrinsic activity of phenylethanolamines on &Beta;-adrenergic receptors and also on the general action on &alpha;-adrenergic receptors.<br><br> For this reason a few phenylethanolamines were synthesized and tested in vitro on the isolated organ preparations of the right atrium and trachea of the guinea pig and the vas deferens of the rat. This was done to test for activity on &Beta;<sub>1</sub>-, &Beta;<sub>2</sub>- and &alpha;-adrenergic receptors. Concentration effect curves of the various results were drawn. From these curves the following conclusions concerning the mechanisms by which these compounds work, were drawn:<br><br> i) The halo- and methoxyprenalines and phenylethanolisopropylamine are antagonists of agonists on the &Beta;-adrenergic (&Beta;<sub>1</sub> and &Beta;<sub>2</sub> receptors. There is still uncertainty about the exact nature of this mechanism. However there are strong suggestions that the antagonism is probably not purely competitive. Possibly a functional or non-competitive antagonistic mechanism or a combination thereof (probably also with competitive antagonism) is responsible for this antagonistic effect.<br><br> ii). Evidence strongly suggests that the halo- and methoxyprenalines and phenylethanolpropylamine are not &Beta;-sympathomimetics and therefore do not have intrinsic activity on &Beta;-adrenergic receptors. Ring halogens do not give rise to intrinsic activity of phenylethanolisopropylamines.<br><br> iii) It was postulated that the halo- and methoxyprenalines and phenylethanolpropylamine are possibly all agonists on a non-adrenergic, non-muscarinic, non-histaminergic, non-neural receptor system that causes smooth muscle relaxation in the tracheal smooth muscle of the guinea pig. A similar system also possibly exists on the right atrium of the guinea pig.<br><br> iv) The halonoradrenalins and phenylethanolamine are partial or full, possibly directly working, agonists on the &alpha;-adrenergic receptor.<br><br> It is evident that complex action mechanisms are involved with the above mentioned halo- an methoxyprenalines. In order to resolve these mechanisms more completely, more intensive research is needed en
dc.language Afrikaans en
dc.subject Medical sciences: Pharmacology and therapeutics en
dc.title Die sintese en farmakodinamika van ringgehalogeneerde fenieletielamienderivate en
dc.type Masters degree en
dc.description.degree MSc en

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