Low dose cocaine self-administration transiently increases but high dose cocaine persistently decreases brain reward function in rats
by
Kenny PJ, Polis I, Koob GF, Markou A.
Department of Neuropharmacology,
CVN-7, The Scripps Research Institute,
10550 North Torrey Pines Road,
La Jolla, CA 92037, USA.
Eur J Neurosci 2003 Jan;17(1):191-5

ABSTRACT

This study investigated the effects of self-administered cocaine on brain reward function, measured by intracranial self-stimulation (ICSS) reward thresholds in rats. Self-administration of 10 and 20 cocaine injections (0.25 mg per injection, equivalent to 4.94 +/- 0.23 and 9.88 +/- 0.46 mg/kg, self-administered over 40 +/- 6.9 and 99 +/- 11.9 min, respectively) lowered reward thresholds 15 min later, indicating a facilitation of rewarding ICSS, but had no effect at 2, 24 or 48 h after administration. Thus, self-administration of low cocaine doses did not cause persistent changes in brain reward function. Forty cocaine injections (19.64 +/- 0.94 mg/kg; self-administered over 185 +/- 10.9 min) also transiently lowered reward thresholds 15 min later, while significant threshold current elevations were observed at 2 and 24 h after administration, indicating persistent withdrawal-like reward deficits. Finally, 80 cocaine injections (39.53 +/- 1.84 mg/kg, self-administered over 376 +/- 19.9 min) significantly elevated thresholds 2 and 48 h after self-administration, but not at 24 h. Threshold currents also tended to be elevated 15 min after self-administration. Overall, these data suggest that as the amount of self-administered cocaine increases the motivation to consume further cocaine may be shifted, from obtaining the rewarding actions of cocaine to avoidance and alleviation of a cocaine-induced negative affective state.

Reward
Delta FosB
Oral cocaine
Dopaminergic flies?
Dopaminergic agents
The coke-craving brain
Cocaine and depression
Cocaine and the lonely rat
Monoamines, cocaine and rats
A disease of the reward centers?
Cocaine, reward and monoamines
Cocaine and the shell of the nucleus accumbens
Does cocaine use damage the pleasure centers?

01 02 03 04 05 06 07 08 09 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24

Refs
HOME
HedWeb
cannabis-marijuana.com
Future Opioids
BLTC Research
Wirehead Hedonism
Paradise-Engineering
Utopian Pharmacology
The Hedonistic Imperative
When Is It Best to Take Crack Cocaine?

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