Caffeine and central noradrenaline: effects on mood, cognitive performance, eye movements and cardiovascular function
by
Smith A, Brice C, Nash J, Rich N, Nutt DJ.
Centre for Occupational and Health Psychology,
School of Psychology, Cardiff University, Cardiff, UK.
smithAP@cardiff.ac.uk
J Psychopharmacol. 2003 Sep;17(3):283-92


ABSTRACT

There have been numerous studies on the effects of caffeine on behaviour and cardiovascular function. It is now important to clarify the mechanisms that underlie such effects, and the main objective of the present study was to investigate whether changes in central noradrenaline underlie some of the behavioural and cardiovascular effects of caffeine. This was examined using a clonidine challenge paradigm. Twenty-four healthy volunteers were assigned to one of four conditions: (i) clonidine/caffeine; (ii) clonidine/placebo; (iii) placebo/caffeine: (iv) placebo/placebo. Baseline measurements of mood, cognitive performance, saccadic eye movements and cardiovascular function were recorded. Subsequently, volunteers were given either clonidine (200 microg) or placebo and consumed coffee containing caffeine (1.5 mg/kg) or placebo. The test battery was then repeated 30 min, 150 min and 270 min later. A second cup of coffee (with the same amount of caffeine as the first) was consumed 120 min after the first cup. The results showed that clonidine reduced alertness, impaired many aspects of performance and slowed saccadic eye movements; caffeine removed many of these impairments. Both clonidine and caffeine influenced blood pressure (clonidine reduced it, caffeine raised it) but the effects appeared to be independent, suggesting that separate mechanisms were involved. In addition, there were some behavioural effects of caffeine that were independent of the clonidine effect (e.g. effects on speed of encoding of new information) and these may reflect other neurotransmitter systems (e.g cholinergic effects). Overall, the results suggest that caffeine counteracts reductions in the turnover of central noradrenaline. This mechanism may underlie the beneficial effects of caffeine seen in low alertness states.

Coffee
Caffeine
Exercise
Guarana
Ampakines
Blueberries
New brain cells
Centrophenoxine
Caffeine and alcohol
The memory switch?
Dumb-drug euphoria
Growing new brain cells
Coffee and caffeine FAQ
Is antioxidant-rich coffee a health drink?
Coffee, caffeine and Parkinson's disease
Caffeine, acetylcholine and the hippocampus
Caffeine/aspirin combo: effects on mood and performance
Is caffeine use protective against cognitive impairment in Alzheimer's?



Refs
and further reading

HOME
HedWeb
Nootropics
cocaine.wiki
Future Opioids
BLTC Research
MDMA/Ecstasy
Superhapiness?
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
The Good Drug Guide

The Responsible Parent's Guide
To Healthy Mood Boosters For All The Family