Lasting effects of repeated Δ9-tetrahydrocannabinol (THC) vapor inhalation during adolescence in male and female rats
Jacques D. Nguyen, Kevin M Creehan, Tony M Kerr, Michael A. Taffe
bioRxiv (Cold Spring Harbor Laboratory) September 25, 2018 preprint DOI: 10.1101/426064 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Controlled animal experiment |
|---|---|
| Population | Male and female adolescent rats (postnatal days 35-45), followed into adulthood |
| Intervention | THC vapor inhalation |
| Duration | Twice daily for 30 minutes from postnatal day 35-39 and 42-45; follow-up from postnatal day 86-94 and in adulthood |
| Measures | radio-telemetry thermoregulatory responses, chow intake, plasma THC levels, intravenous self-administration of oxycodone, fentanyl self-administration |
| Topics | Cannabis |
| Citations | 9 |
| Key findings | Repeated adolescent THC vapor inhalation produced lasting effects in rats: females, but not males, developed tolerance to THC-induced hypothermia during adolescence despite similar plasma THC levels, and both sexes showed adult tolerance with greater potency in females. THC-exposed males ate more chow than controls without weight differences, and THC increased adult fentanyl self-administration in females but did not alter oxycodone self-administration in either sex. |
Abstract
Abstract Adolescents are regularly exposed to Δ 9 -tetrahydrocannabinol (THC) via smoking, and, more recently, vaping, cannabis / extracts. Growing legalization of cannabis for medical and recreational purposes, combined with decreasing perceptions of harm, makes it increasingly important to determine the consequences of frequent adolescent exposure for motivated behavior and lasting tolerance in response to THC. Male and female rats inhaled THC vapor, or that from the propylene glycol (PG) vehicle, twice daily for 30 minutes from postnatal day (PND) 35-39 and PND 42-45 using an e-cigarette system. Thermoregulatory responses to vapor inhalation were assessed by radio-telemetry during adolescence and from PND 86-94; chow intake was assessed in adulthood. Blood samples were obtained from additional adolescent groups following initial THC inhalation and after four days of twice daily exposure. Additional groups exposed repeatedly to THC or PG during adolescence were evaluated for intravenous self-administration of oxycodone as adults. Female, not male, adolescents developed tolerance to the hypothermic effects of THC inhalation in the first week of repeated exposure despite similar plasma THC levels. Each sex exhibited tolerance to THC hypothermia in adulthood after repeated adolescent THC with THC greater potency exhibited in females. Repeated-THC male rats consumed more food than their PG treated control group, in the absence of a significant bodyweight difference. Adolescent THC did not alter oxycodone self-administration in either sex, but increased fentanyl self-administration in females. Repeated THC vapor inhalation in adolescent rats results in lasting consequences observable in adulthood. Abbreviations PG, propylene glycol; THC, Δ 9 tetrahydrocannabinol;
Comparable studies
Other preclinical and animal studies on cannabis, most cited first.
Citations in the library
Cites 11
- Δ9-tetrahydrocannabinol attenuates oxycodone self-administration under extended access conditions. Neuropharmacology June 1, 2019
- Effects of Δ9-THC and cannabidiol vapor inhalation in male and female rats. Psychopharmacology September 2018
- Tolerance to hypothermic and antinoceptive effects of ∆9-tetrahydrocannabinol (THC) vapor inhalation in rats. Pharmacology, Biochemistry, and Behavior September 2018
- Escalation of intravenous self-administration of methylone and mephedrone under extended access conditions. Addiction Biology September 2017
- Chronic THC during adolescence increases the vulnerability to stress-induced relapse to heroin seeking in adult rats. European Neuropsychopharmacology July 2014
and 6 more in the library