PROP taster status and parental history of alcohol dependence.

Pelchat and Danowski [Physiol. Behav. 1992;51:1261-1266] reported an association between the ability to taste 6-n-propylthiouracil (PROP) and a parental history of alcoholism. Kranzler et al. [Alcohol Clin. Exp. Res. 1996a;20:1496-1500] previously failed to replicate these findings in a sample of subjects with only a paternal history of alcohol dependence. The present study was conducted to examine this putative association in a sample of subjects that is heterogeneous with respect to parental alcoholism history. Among the 90 alcohol-dependent subjects studied, the proportion of PROP nontasters was comparable to that observed among nonalcoholics. Analysis revealed no association of parental history with PROP taster status, even after controlling for potential confounding variables. We conclude that no reliable association exists between taste sensitivity to PROP and either a diagnosis of alcohol dependence or a parental history of alcohol dependence.

Utility of the AUDIT for identification of hazardous or harmful drinking in drug-dependent patients.

We evaluated the psychometric properties of the alcohol use disorders identification test (AUDIT), a ten-item screening test for identification of hazardous drinkers, in a sample of 82 patients with DSM-III-R drug dependence. AUDIT showed good internal consistency (alpha = 0.94) and a unitary factor structure. Receiver operating characteristics analysis showed the AUDIT to be comparable to the Michigan alcoholism screening test (MAST) in identifying individuals with a current alcohol use disorder and superior to the MAST for those who are hazardous drinkers. In this patient sample, AUDIT performed well at the recommended cut-off score of > or = 8. We recommend use of the AUDIT for identification of hazardous and harmful drinking among individuals with a drug use disorder.

No association between D3 dopamine receptor (DRD3) alleles and cocaine dependence.

Cocaine is thought to act in the brain primarily by blocking dopamine re-uptake. The dopamine D3 receptor (genetic locus DRD3) is localized to brain regions that have been implicated in the reinforcing effects of a number of substances of abuse, including cocaine. The DRD3 coding region contains a polymorphism identifiable as a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). This polymorphism leads to an amino acid substitution at position 9 in the extracellular N-terminus of the D3 dopamine receptor. We examined alleles of the DRD3 gene in cocaine dependence using a genetic association strategy in samples of 62 white and 62 black cocaine-dependent individuals. Comparisons were made with local (Connecticut) control subjects for both groups, and with a larger sample of literature controls (for the white subjects) and a contrast group of schizophrenic patients (for the black subjects). No association was found between cocaine dependence and DRD3 alleles in either group (Bonferroni corrected). There was a significant difference in allele frequency between whites and blacks. These results are consistent with no role for genetic variation of the D3 dopamine receptor in susceptibility to cocaine dependence.

Brain dopamine response in isolated 10-day-old rats: assessment using D2 binding and dopamine turnover.

A single 5-min isolation from the nest, dam, and siblings in 10-day-old rat pups was investigated for its effect on brain dopamine systems. The release of dopamine in innervated brain regions was measured in separate studies using in vivo ligand binding of 3H-raclopride, ex vivo binding using 3H-raclopride, and neurochemical measurement of the dopamine turnover using levels of DOPAC and dopamine. In addition, in vitro homogenate binding was performed to determine baseline Bmax and Kd values for 3H-raclopride binding sites across treatments. Isolation for 5 min in a "novel" environment resulted in decreased 3H-raclopride binding in striatum and septum as determined by both in vivo and ex vivo binding, as well as increased dopamine turnover. There was no difference in Bmax and Kd values for 3H-raclopride in these brain regions after the 5-min isolation, indicating that the binding decreases were due to an increase of available dopamine, presumably from terminal release. The convergence of results from three different techniques supports the interpretation that dopamine is released during the 5-min isolation in both brain regions.