Noradrenaline acts as a neurotransmitter between sympathetic postganglionic nerves and the organs they innervate. When an action potential reaches the nerve terminal, noradrenaline is released into the synaptic cleft and binds to alpha adrenoreceptors on nearby cells. This causes vasoconstriction and increases both systolic and diastolic blood pressure, raising mean arterial pressure. Noradrenaline interacts with various other drugs and medications and can cause side effects like anxiety, dizziness, and tremors. It should be used cautiously in patients with certain medical conditions.
1. It acts as the neurotransmitter between sypathetic post
ganglionic nerves and the organs they innervate. Arrival
of an action potential a the nerve terminal of the post
ganglionic neuron causes the release of noradrenaline
into the junctional synaptic cleft between neurons. It then
diffuses across the cleft to the receptor (adrenoceptor)
sites specifically alpha adrenocpetors on the post
junctional membrane of neuroeffector cells (smooth
muscle, cardiac muscle or glands). In persistent
hypotensive state, once blood volume deficit has been
corrected noradrenaline helps to raise blood pressure to
an optimum level
2. The main therapeutic effect of noradrenaline
results from peripheral arteriolar
vasoconstriction in all vascular beds. Both
systolic and diastolic blood pressure are
elevated causing a rise in mean
arterial pressure.
Half life of noradrenaline ranges between
30seconds to 3 minutes.
3. Interacts with β-blocking agents, digitalis
glycosides, tricyclic antidepressants,
mono-amine oxidase inhibitors, cocaine
and oxytocics.
5. Should be used with caution in patients with
atherosclerosis, mesentric and peripheral
vascular thrombosis or other occlusive
vascular diseases, metabolic acidosis, hypoxia
or hyperthyroidism. It should be avoided in
patients who are hypersensitive to sodium
metabisulfite (which is the preservative in the
solution).
6. Knights, K & Kathleen, B 2011, Pharmacology for health professionals,
Chapter 12, Elsevier, Chatswood, Australia.
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