noradrenaline
Học thuậtThân thiện
Definition
Noun: A neurotransmitter and hormone that is chemically a catecholamine. It functions as a precursor to epinephrine (adrenaline) and is secreted by the adrenal medulla. It is also a key chemical released by neurons at synapses in the nervous system, where it acts to transmit nerve impulses, particularly in the sympathetic nervous system, influencing functions like alertness, heart rate, and blood pressure.
Usage
Noradrenaline is primarily used in scientific, medical, and physiological contexts. - It is often discussed in relation to the body's "fight-or-flight" response. - In pharmacology, drugs that affect noradrenaline levels are used to treat conditions like depression and low blood pressure.
Examples
- Medical Context:
- The doctor explained that the medication works by increasing the level of noradrenaline in the brain.
- A sudden shock can trigger a rapid release of noradrenaline.
- Physiological Context:
- Noradrenaline is crucial for maintaining blood pressure during sudden postural changes.
- The sympathetic nerves release noradrenaline to accelerate the heart rate.
Advanced Usage
- "Noradrenaline reuptake inhibitor (NRI)": A class of drugs that block the reabsorption of noradrenaline into neurons, increasing its availability in the synapse.
- The antidepressant is a selective noradrenaline reuptake inhibitor.
- "Noradrenaline surge": A rapid, significant increase in noradrenaline levels, typically in response to stress.
- The athlete experienced a noradrenaline surge at the start of the race.
Variants and Related Words
- Norepinephrine (n): The most common synonym for noradrenaline, especially in American English medical literature.
- The terms 'noradrenaline' and 'norepinephrine' refer to the same chemical compound.
- Adrenaline/Epinephrine (n): A related hormone and neurotransmitter synthesized from noradrenaline.
- Catecholamine (n): The broader class of organic compounds to which noradrenaline belongs.
Synonyms
- Norepinephrine: The direct synonym.
- Levarterenol: A less common pharmaceutical name.
Related Phrases and Compounds
- Noradrenergic (adj): Describing neurons or pathways that use noradrenaline as their neurotransmitter.
- Noradrenergic pathways are involved in arousal and attention.
- Alpha-adrenergic receptor: A type of receptor on cells that noradrenaline binds to, mediating many of its effects.
- The drug blocks alpha-adrenergic receptors to lower blood pressure.
Noun
- a catecholamine precursor of epinephrine that is secreted by the adrenal medulla and also released at synapses