ENHANCED NOREPINEPHRINE RELEASE IN PREFRONTAL CORTEX WITH BURST STIMULATION OF THE LOCUS-COERULEUS

Citation
Sm. Florinlechner et al., ENHANCED NOREPINEPHRINE RELEASE IN PREFRONTAL CORTEX WITH BURST STIMULATION OF THE LOCUS-COERULEUS, Brain research, 742(1-2), 1996, pp. 89-97
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences
Journal title
ISSN journal
0006-8993
Volume
742
Issue
1-2
Year of publication
1996
Pages
89 - 97
Database
ISI
SICI code
0006-8993(1996)742:1-2<89:ENRIPC>2.0.ZU;2-Z
Abstract
The present study was designed to determine the relationship between t he discharge of noradrenergic locus coeruleus (LC) neurons and norepin ephrine release in the medial prefrontal cortex, a target of LC projec tions. The LC was electrically stimulated at varying frequencies and p atterns for 20 min and extracellular norepinephrine levels were measur ed in the medial prefrontal cortex of halothane-anesthetized rats usin g in vivo microdialysis. Electrical stimulation of the LC at 3-10 Hz w ith an evenly spaced pattern of pulses (tonic stimulation) increased c ortical norepinephrine levels in a frequency-dependent manner, with 5- and 10-Hz stimulation increasing norepinephrine levels by 49 +/- 3% a nd 66 +/- 20%, respectively. The LC was also stimulated with bursts oi pulses designed to deliver physiologically relevant phasic stimulatio n using the same number of stimuli in a 20-min period as delivered by tonic stimulation at 3 Hz. Results revealed that norepinephrine levels were significantly higher with phasic stimulation compared to tonic s timulation. The present findings indicate that both frequency and patt ern of LC discharge are determinants of norepinephrine terminal releas e. Additionally, bursts of LC activity, similar to those that occur in behaving animals, may be more effective in increasing terminal norepi nephrine release on a per spike basis than tonic increases in activity .