Changes in striatal D2-receptor density following chronic treatment with amphetamine as assessed with PET in nonhuman primates
by
Ginovart N, Farde L, Halldin C, Swahn CG
Karolinska Institutet,
Department of Clinical Neuroscience,
Karolinska Hospital, Stockholm, Sweden.
nathalie@cermep.fr
Synapse 1999 Feb; 31(2):154-62

ABSTRACT

Recent brain imaging studies suggest that schizophrenia may be related to abnormally high amphetamine-induced dopamine release. It is known that repeated use of amphetamine may cause paranoid psychosis and persisting stereotypies. The biochemical background for these signs and symptoms has not been clarified. In this study, positron emission tomography and [11C]raclopride were used to determine central D2-dopamine receptor density (Bmax) and apparent affinity (K(D)app) in Cynomolgus monkeys before and after 14 days of treatment with d-amphetamine sulphate (2 mg/kg/day; s.c.). One day after withdrawal from amphetamine, K(D)app was increased, suggesting [11C]raclopride competition with elevated concentration of dopamine. At 7 and 14 days after withdrawal, there was a 19-26% decrease in Bmax but no change in K(D)app as compared to baseline. Although this study was performed on two monkeys only, there was thus no support for the view that chronic intermittent hyperactivity of the dopamine system may be related to an upregulation of striatal D2-dopamine receptors. Repeated administration of amphetamine may, rather, cause a long-lasting downregulation of the D2-receptor density, which may be a neurochemical correlate to the abnormal movements, anhedonia, anxiety, and depression seen in psychostimulant abusers.

D1+D2
Anxiety
Anhedonia
Rats on ice
Methamphetamine
Retarded depression
Amphetamine psychosis
Arachnids on Benzedrine

Refs
HOME
HedWeb
Future Opioids
BLTC Research
amphetamines.com
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