ArticlePsychopharmacology2026
Impact of sex on heroin intravenous self-administration by heterogeneous stock rats.
Article in Psychopharmacology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
1 citing paper in PubMed.
- Impact of Age on Heroin Intravenous Self-Administration in Wistar Rats.bioRxiv : the preprint server for biology · 2026Article
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4 authors.
Funding
Abstract
backgroundIntravenous self-administration (IVSA) of opioids by rats has been shown frequently to exhibit no sex differences, in many cases a higher intake of females, and only rarely higher rates in males. A diversity of methodological parameters (opioid identity, training doses, rat strain, session duration) makes it difficult to identify consistent contributions to these outcomes.
objectiveTo determine if Heterogeneous Stock (HS) rats derived from 8 founder strains differ by sex in the IVSA of opioids.
methodsMale and female Heterogeneous Stock (N = 7-8 per sex) rats were permitted to self-administer heroin (20 µg/kg/infusion) in 2 h sessions under a Fixed Ratio 1 schedule of reinforcement. After acquisition, animals completed sessions in which different infusion doses of heroin (0, 15, 30, 60, 120 µg/kg/infusion), oxycodone (0, 30, 60, 150, 300 µg/kg/infusion) and fentanyl (0, 0.625, 1.25, 2.5, 5.0 µg/kg/infusion) were assessed. Next, animals were evaluated on doses of heroin (15, 30, 60, 120 µg/kg/infusion), oxycodone (30, 60, 150, 300 µg/kg/infusion) and fentanyl (0.625, 1.25, 2.5, 5.0 µg/kg/infusion) under a Progressive Ratio schedule. Anti-nociceptive effects of heroin (0.56-2.4 mg/kg, s.c.) were examined with a warm water tail-withdrawal assay.
resultsFemale HS rats consistently self-administered more infusions of opioids, including heroin during acquisition, all three opioids during FR-1 dose substitution and of oxycodone and fentanyl in the PR procedure. Male rats were moderately more sensitive to the anti-nociceptive effects of heroin.
conclusionsFemale rats drawn at random from a genetically diverse population self-administer opioids at higher rates than their male counterparts.
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