Norepinephrine

Norepinephrine (NE) is a catecholamine that acts as a hormone outside the brain and a neuromodulator inside.

Location
NE is primarily located in adrenergic neurons within the locus coeruleus of the pons.

Function

 * At synapses onto CA1 neurons, β-adrenergic agonists enlarged the window of time in which STDP could occur.
 * β-Adrenergic receptor agonists found to gate induction of NMDAR dependent LTP in L2/3 visual cortical neurons. α1-adrenergic receptor agonist coupled to PLC enabled LTD. β-Adrenergic agonist with M1R agonist together produced typical STDP.
 * Likely has a pivotal role in sleep-wake regulation.
 * NE lacking mice failed to redistribute tonotopic maps.
 * NE can activate ERK pathway in cultured cells, and it's possible to reproduce similar changes in vivo seen from sleep deprivation in vitro.
 * LC and NE is becoming associated with novelty as  Dopamine  is. It has been found that optically activating NE-positive cells presumably in the LC can enhance memory retention in mice. In addition, this enhancement appears to be dependent on co-release of dopamine in the  Hippocampus.