tailieunhanh - CLINICAL PHARMACOLOGY 2003 (PART 24)

Anyone who administers drugs acting on cardiovascular adrenergic mechanisms requires an understanding of how they act in order to use them to the best advantage and with safety. Adrenergic mechanisms Classification of sympathomimetics: by mode of action and selectivity for adrenoceptors Individual sympathomimetics Mucosal decongestants Shock Chronic orthostatic hypotension Adrenaline, noradrenaline and dopamine are formed in the body and are used in therapeutics. The natural synthetic path is: tyrosine — dopa — dopamine — noradrenaline — adrenaline. Classification of sympathomimetics BY MODE OF ACTION Noradrenaline is synthesised and stored in adrenergic nerve terminals and can be released from these stores by stimulating. | 22 I__ SECTION 5 Adrenergic mechanisms and drugs SYNOPSIS Anyone who administers drugs acting on cardiovascular adrenergic mechanisms requires an understanding of how they act in order to use them to the best advantage and with safety. Adrenergic mechanisms Classification of sympathomimetics by mode of action and selectivity for adrenoceptors Individual sympathomimetics Mucosal decongestants Shock Chronic orthostatic hypotension Adrenergic mechanisms The discovery in 1895 of the hypertensive effect of adrenaline epinephrine was initiated by Dr Oliver a physician in practice who conducted a series of experiments on his young son into whom he injected an extract of bovine suprarenal. The effect was confirmed in animals and led eventually to the isolation and synthesis of adrenaline in the early 1900s. Many related compounds were examined and in 1910 Barger and Dale invented the word sympathomimetic1 and also pointed out that noradrenaline norepinephrine mimicked the action of the sympathetic nervous system more closely than did adrenaline. Adrenaline noradrenaline and dopamine are formed in the body and are used in therapeutics. The natural synthetic path is tyrosine dopa - dopamine noradrenaline adrenaline. Classification of sympathomimetics BY MODE OF ACTION Noradrenaline is synthesised and stored in adrenergic nerve terminals and can be released from these stores by stimulating the nerve or by drugs ephedrine amfetamine . These noradrenaline stores may be replenished by . infusion of noradrenaline and abolished by reserpine or by cutting the sympathetic neuron. Sympathomimetics may be classified as those that act 1. directly adrenoceptor agonists . adrenaline 1 Compounds which . simulate the effects of sympathetic nerves not only with varying intensity but with varying precision . a term . seems needed to indicate the types of action common to these bases. We propose to call it sympathomimetic . A term which indicates the relation of the action to .