Produces vasocontriction and myocardial stimulation,which may be required after adequate fluid replacement in the treatment of shock.
Norepinephrine (INN) or noradrenaline (BAN) is a catecholamine and a phenethylamine with chemical formula C8H11NO3. Increased blood pressure, Increased cardiac output.The natural stereoisomer is L-(−)-(R)-norepinephrine. It is released from the medulla of the adrenal glands as a hormone into the blood, but it is also a neurotransmitter in the central nervous system and sympathetic nervous system where it is released from noradrenergic neurons during synaptic transmission.Stimulated alpha-adrenergic receptors located mainly in in the blood vessels causing constriction of both capacitance and resistance vessel. As a stress hormone, it affects parts of the human brain where attention and responding actions are controlled. Along with epinephrine, norepinephrine underlies the fight-or-flight response, directly increasing heart rate, triggering the release of glucose from energy stores, and increasing skeletal muscle readiness.
Norepinephrine is released when a host of physiological changes are activated by a stressful event. This is caused in part by activation of an area of the brain stem called the locus ceruleus. This nucleus is the origin of most norepinephrine pathways in the brain. Neurons that are activated by norepinephrine project bilaterally (send signals to both sides of the brain) from the locus ceruleus along distinct pathways to many locations, including the cerebral cortex, limbic system, and the spinal cord.
At synapses, norepinephrine acts on both alpha and beta.
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