铁素相关的内分泌学变化在发红细胞瘤和偏角细胞瘤

Enzyme-linked receptors are cell-surface receptors acting as an enzyme or associating with an enzyme intracellularly. They make excellent drug targets. Drugs can bind to the extracellular ligand-binding domain or directly affect their enzymatic domain and alter their activity.
Major types that are helpful drug targets include:

Postganglionic sympathetic fibers (except those supplying the sweat glands) releasing noradrenaline or norepinephrine are called noradrenergic or adrenergic neurons. Noradrenaline, dopamine, adrenaline, or epinephrine are collectively called "catecholamines" as they contain a catechol moiety and an amine side chain. The five stages of neurotransmitter release involve their synthesis, storage, release, reuptake and metabolism.
Synthesis: Catecholamine synthesis requires tyrosine, which...

Certain drugs can affect how neurotransmitters called catecholamines, are released or taken back up in the adrenergic neuron. They can have different effects on the body's sympathetic transmission. Reserpine, a natural compound found in the Rauwolfia shrub, blocks a transporter called vesicular monoamine transporter (VMAT), which leads to a buildup of catecholamines in the cell and reduces sympathetic transmission. Another drug called guanethidine works in multiple ways, including blocking...

Sympathetic signaling, a vital part of the autonomic nervous system, plays a crucial role in mobilizing the body's resources in response to stress or emergencies. It involves the transmission of nerve impulses from sympathetic preganglionic fibers to postganglionic fibers. This results in the release of specific neurotransmitters and activation of adrenergic receptors.
Sympathetic preganglionic fibers release the neurotransmitter acetylcholine (ACh) onto the ganglionic neurons in the...

Indirect-acting adrenergic agonists potentiate the effects of endogenous catecholamines through different mechanisms without directly binding to adrenoceptors.
One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral...

Drugs affecting neurotransmitter synthesis can impact the adrenergic neuron and the synthesis of neurotransmitters. For example, α-methyltyrosine and carbidopa target specific enzymes involved in catecholamine synthesis. α-methyltyrosine inhibits the enzyme tyrosine hydroxylase, which converts tyrosine into dopamine. By blocking this enzyme, α-methyltyrosine reduces dopamine production and other catecholamines. Carbidopa, on the other hand, inhibits the enzyme dopa decarboxylase,...