Noradrenalin & Receptors
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- Bu səhifədəki naviqasiya:
- Alpha Receptors Alpha Receptors
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Noradrenalin & Receptors Noradrenalin & Receptors • •
A brief information about the NT • • Receptor types Receptor types • •
Action mechanisms • • Noradrenalin works both as a neurotransmitter Noradrenalin works both as a neurotransmitter in the CNS and as a hormone when it is released in the CNS and as a hormone when it is released by the adrenal gland with adrenalin. by the adrenal gland with adrenalin. • • Noradrenalin is released from the adrenal glands Noradrenalin is released from the adrenal glands during stress. during stress. • •
In the brain the brain it
it plays
plays a a crucial crucial
role in role in
arousing the arousing the body, for example from sleep. body, for example from sleep. • •
High level of noradrenalin leads to hypersensitivity hypersensitivity • • Low level is related to poor concentration and Low level is related to poor concentration and depression depression • •
Acts on adrenergic receptors Release of noradrenalin Release of noradrenalin Synthesis pathway of Noradrenalin Synthesis pathway of Noradrenalin Adrenergic Receptor types & Family Adrenergic Receptor types & Family Alpha Receptors Alpha Receptors Alpha 1
Alpha 1 • • Predominant form of alpha receptor in Predominant form of alpha receptor in the body. the body. • •
Found primarily in the smooth muscles of arterioles, eye, gut, skin, veins, etc., as arterioles, eye, gut, skin, veins, etc., as well as in some other cell types (like well as in some other cell types (like salivary glands). salivary glands). • • Usually causes contraction of smooth Usually causes contraction of smooth muscle cells. muscle cells. Alpha 2 Alpha 2
• • Found at pre Found at pre - - synaptic terminals of synaptic terminals of adrenergic nerves. adrenergic nerves. • •
Functions as an autoreceptor. If stimulated, it decreases the subsequent stimulated, it decreases the subsequent release of transmitter. release of transmitter. • • When an agonist binds to an When an agonist binds to an α α
2 - - receptor, receptor, cyclic AMP levels within the cell decrease. cyclic AMP levels within the cell decrease. Beta Beta
Receptors Receptors Beta 1 Beta 1
• • Found in heart muscle, and in the kidney. Found in heart muscle, and in the kidney. • • Causes increased heart rate and Causes increased heart rate and contractility. contractility. • •
Promotes release of renin from the kidney Beta 2 Beta 2
• • Found in smooth muscle that relaxes upon Found in smooth muscle that relaxes upon stimulation, and in metabolic tissues stimulation, and in metabolic tissues • • Decrease in gastrointestinal motility. Decrease in gastrointestinal motility. • •
Vasodilation in skeletal and cardiac muscle.
muscle. Beta 3 Beta 3
• • β β 3 receptors are only found on brown adipose 3 receptors are only found on brown adipose tissue.
tissue. • • Stimulates lipolysis, increasing fatty acids in the Stimulates lipolysis, increasing fatty acids in the blood. blood.
• • Adults don't have much brown adipose tissue, Adults don't have much brown adipose tissue, but babies have lots. The role of brown adipose but babies have lots. The role of brown adipose tissue is thermogenesis tissue is thermogenesis - - as blood passes as blood passes through the brown adipose tissue it gets through the brown adipose tissue it gets warmed up. warmed up. Signal Transduction Mechanism; Beta Receptors Signal Transduction Mechanism; Beta Receptors 2 2 Drug Examples Drug Examples : : • • Monoamine oxidase inhibitors & Monoamine oxidase inhibitors & amphetamine; Increase the free amphetamine; Increase the free noradrenalin and elevate mood. noradrenalin and elevate mood. • • Desipramine; Elevates the mood by Desipramine; Elevates the mood by decreasing the reuptake of liberated decreasing the reuptake of liberated noradrenalin. noradrenalin. Prepared by Prepared by ; ;
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