Peripheral benzodiazepine receptors are decreased during cocaine withdrawal in humans.
In the present study, homovanillic acid in plasma (pHVA) and benzodiazepine receptors (3H-PK11195 binding) in neutrophil membranes were determined in blood obtained from cocaine-dependent (DSM-III-R) adult male inpatients at baseline-(within 72 hr of last cocaine use) and after 3 weeks of cocaine abstinence, and normal controls. The mean (+/- SEM) pHVA at baseline (10.3 ng/ml +/- 1.1) was similar to normals and did not change after 3 weeks of cocaine abstinence. Similarly, the binding indices of benzodiazepine receptors in cocaine-dependent subjects as a group were not significantly different than in normal controls. In 10 cocaine-dependent subjects, however, where both blood samples were available, the number of 3H-PK11195 binding sites was significantly (p < 0.05) decreased after 3 weeks of cocaine abstinence (mean +/- sem: Bmax = 6371 +/- 657 fmol/mg protein) compared with baseline (Bmax = 7553 +/- 925 fmol/mg protein), although there were no differences in the binding affinity (mean +/- sem: KD = 8.6 +/- 1.2 nmol/L after 3 weeks of abstinence compared with 8.1 +/- 1.0 nmol/L at baseline). These preliminary results suggest that peripheral benzodiazepine receptors may play an important role in the pathophysiology of cocaine withdrawal in cocaine-dependent human subjects.
Javaid
J I
JI
Illinois State Psychiatric Institute, Chicago 60651.
Notorangelo
M P
MP
Pandey
S C
SC
Reddy
P L
PL
Pandey
G N
GN
Davis
J M
JM
D000328:Adult; D003042:Cocaine / Q000009:adverse effects*; D006719:Homovanillic Acid / Q000097:blood; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D011869:Radioligand Assay; D011963:Receptors, GABA-A / Q000378:metabolism*; D013375:Substance Withdrawal Syndrome / Q000378:metabolism*
D011963:Receptors, GABA-A; D003042:Cocaine; D006719:Homovanillic Acid