Correct Answer - Option 2 : Neurotransmitter
Concept:
Noradrenaline also called as Norepinephrine, is a neurotransmitter.
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone and neurotransmitter.
Neurotransmitter, also called chemical transmitter or chemical messenger, any of a group of chemical agents released by neurons (nerve cells) to stimulate neighbouring neurons or muscle or gland cells, thus allowing impulses to be passed from one cell to the next throughout the nervous system.
The general function of Noradrenaline is to mobilize the brain and body for action. It releases the lowest during sleep, rises during wakefulness, and reaches much higher levels during situations of stress or danger, so it is called fight-or-flight response.
In the brain, Noradrenaline increases arousal and alertness, promotes vigilance, enhances formation and retrieval of memory, and focuses attention. It also increases restlessness and anxiety. In the rest of the body, it also increases heart rate and blood pressure triggers the release of glucose from energy stores, increases blood flow to skeletal muscle, reduces blood flow to the gastrointestinal system, and inhibits voiding of the bladder and gastrointestinal motility.
