ADRENERGIC SYSTEM AND DRUGS SUMMARISED NOTES

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ADRENERGIC SYSTEM AND DRUGS This system is also referred to as Sympathetic system while the drugs involved can be described as sympathomimetic or adrenergic drugs. The main neurotransmitter invo... lved is called noradrenaline while adrenaline acts as a hormone. These two are synthesized in ratio of 80% to 20% in adrenal medulla. There are three closely related substances called catecholamines namely;  Noradrenaline which is the neurotransmitter at post-ganglionic sympathetic sites (except at sweat glands and hair follicles) and certain areas of the brain.  Adrenaline secreted by adrenal medulla.  Dopamine which is a neurotransmitter in the brain. Synthesis of catecholamines Catecholamines are synthesized from amino acid phenylalanine. Tyrosine hydroxylase is the rate limiting step and its inhibition by α-methyl-para-tyrosine results in depletion of catecholamines. This can be used in phaechromocytoma before surgery and in inoperable cases. α-methyl dopa can also interfere with the synthesis of catecholamines. All enzymes involved in catecholamines synthesis are rather non-specific and can act on closely related substrates, for example [Show More]

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