392: GWAS of Cocaine Self-Administration in Heterogeneous Stock Rats

Lara MK et al et al., Nature Communications - Large GWAS in 836 outbred HS rats identifies six loci linked to cocaine self-administration traits, highlighting Ces1 carboxylesterase genes and other loci overlapping human substance-use genetics. Key terms: cocaine use disorder, GWAS, Heterogeneous Stock rats, Ces1, addiction-like behavior.

Study Highlights:
The study performed a genome-wide association analysis in 836 Heterogeneous Stock rats tested in extended-access cocaine self-administration paradigms and derived 27 behavioral traits. Six genome-wide significant loci were identified, including a chromosome 19 locus containing missense variants in Ces1c and Ces1d that are orthologous to human CES1 and associated with post-infusion interval. SNP-based heritability for traits was modest (h2 = 0.07–0.16) with the first LgA principal component showing the highest heritability (h2 = 0.16). Several loci contained coding variants and eQTL/sQTLs in brain regions, and one locus overlapped the rat homolog of human TRAK2.

Conclusion:
This largest-to-date rat GWAS of cocaine self-administration implicates drug-metabolizing carboxylesterases (Ces1c/Ces1d) and multiple neural genes in addiction-like behaviors, supports cross-species links to human SUD loci such as TRAK2, and highlights CES1-related pharmacological strategies as a potential avenue for follow-up.

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Article title:
Genome-wide association study of cocaine self-administration behavior in Heterogeneous Stock rats

First author:
Lara MK et al

Journal:
Nature Communications

DOI:
10.1038/s41467-026-73694-w

Reference:
Lara MK et al., Genome-wide association study of cocaine self-administration behavior in Heterogeneous Stock rats. Nature Communications (2026). https://doi.org/10.1038/s41467-026-73694-w

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

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Episode link: https://basebybase.com/episodes/gwas-cocaine-hs-rats-ces1

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-06-12.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited portions of the transcript that cover: HS rat GWAS design and results; the chromosome 19 Ces1c/Ces1d locus and its link to post-infusion interval; metabolic role of Ces1 in cocaine breakdown; cross-species Trak2 findings; Rasd2/Gnas brain-region eQTLs; PC1 heritability; and broader discussion of implications an
- transcript topics: Gwas in heterogeneous stock rats and six significant loci; Chromosome 19 Ces1c/Ces1d locus and post-infusion interval; Carboxylesterase Ces1 enzymes metabolizing cocaine; Trak2/TRAK2 cross-species overlap with human CUD; Rasd2 and Gnas expression in nucleus accumbens and cortex; LgA PC1 addiction-like behavior and heritability

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Six genome-wide significant associations identified for cocaine self-administration traits in HS rats
- Chromosome 19 locus containing Ces1c and Ces1d associated with post-infusion interval
- Ces1 enzymes metabolize cocaine and influence duration/intensity of effects
- Trak2 is the rat ortholog of human TRAK2 and overlaps human CUD GWAS signals
- Rasd2 and Gnas show brain-region eQTLs related to cocaine response
- LgA PC1 addiction-like behavior explains ~55% of variance with SNP-based heritability up to 0.16

QC result: Pass.