Differences Between Adrenaline and Noradrenaline
Posted October 4, 2022 by Anusha ‐ 2 min read
Adrenaline (Epinephrine), Noradrenaline (Norepinephrine) and Dopamine are amongst a group called catecholamine, which functions as neurotransmitters and hormones within the human body. These three compounds are naturally occurring and are produced in the body. Isoprenaline, unlike the others, is a synthetic catecholamine and is not naturally present in the body.
Difference between Adrenaline and Noradrenaline
| ADRENALINE | NORADRENALINE |
|---|---|
| Almost exclusively made in the adrenal medulla. | Predominantly made in the sympathetic nervous system. |
| More Adrenaline is released from the adrenal medulla than Noradrenaline. | More Noradrenaline is released from the sympathetic nervous system than Adrenaline. |
| Acts mainly as a hormone and is released primarily by the adrenal medulla into the bloodstream. Hence, we can say that Adrenaline is carried throughout the whole body and acts at different organs on different adrenergic receptors. | Function mainly as a neurotransmitter at the synapse between neurons when released from sympathetic neurons (stored in vesicles). Noradrenaline is released at a small concentration as a hormone in the blood circulation by the adrenal medulla. |
| Synthesised from Noradrenaline. | Synthesised from Dopamine. |
| Activates the alpha and beta-adrenergic receptors, and as such, has a wide-range effect. Relatively non-specific and more or less equal at activating the adrenergic receptors. | Activates mainly the alpha-adrenergic receptors and acts on beta receptors to a certain degree (seen to act on beta 1 rather than beta 2 but not as strong as the alpha receptors). |
| Response: constricts minute blood vessels network but dilates blood vessels in the skeletal muscle, increases heart rate and forces of contraction of the heart which increase the cardiac output leading to an increase in blood pressure, increases renin release, bronchodilation from the relaxation of smooth muscles, increase in carbohydrate metabolism (glycogen to glucose and increase glycolysis), increase the utilisation of free fatty acids, increase Glucagon secretion and increase ACTH secretion at the pituitary gland. The metabolic aim is to increase energy usage and availability. | Response: increases and maintain blood pressure through peripheral vasoconstriction of blood vessels. Has been noted to stimulate the inotropy of the heart and dilates coronary arteries. |
| Used in medicine for: severe asthma attacks, anaphylactic shock (acute systemic allergic reaction), glaucoma or eye surgery to maintain dilated pupils, low blood pressure associated with septic shock, cardiac arrest and added to local anaesthetic solutions. | Used in medicine for: emergency low blood pressure used in an acute situation (vasodilatory shock states). These could be from: cardiac arrest, spinal anaesthesia, septicaemia, blood transfusions or drug reactions. Noradrenaline is generally given with an additional agent and can be used in a patient with critical hypotension. |
| Toxicity: sympathomimetic adverse effect. Caution in pregnancy, labour and delivery. | Toxicity: if in overdose and given with another vasopressor, the effect may cause limb ischaemia and limb death. |