Dissertation
INVESTIGATING THE IMPACTS OF MATERNAL CANNABIS USE ON DEVELOPING OFFSPRING IN RATS
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004603
Handle:
https://hdl.handle.net/2376/125307
Abstract
Cannabis is one of the most commonly used recreational drugs during pregnancy. Despite its increasing popularity, research on the risks of prenatal cannabis exposure has remained limited. This dissertation details my efforts to profile the impact of prenatal cannabis exposure on emotional reactivity, cannabis-seeking behavior, and parvalbumin interneuron expression in offspring. I utilized an innovative model to allow female rats to self-administer tetrahydrocannabinol (THC)-rich cannabis (70% THC; 150 mg/mL) or vehicle vapor in a response-contingent manner. A third group of dams did not self-administer vapor during pregnancy. I used age-appropriate tests to examine emotional reactivity in offspring. Cannabis-seeking behavior was investigated in a separate cohort of offspring using a 22-day paradigm where rats self-administered either cannabis or vehicle vapor under increasing schedules of reinforcement. A final group of offspring underwent immunohistochemical analysis of parvalbumin interneurons in the medial prefrontal cortex. I found that dams assigned to the cannabis group earned more vapor deliveries and showed greater preference for the vapor-paired, “active,” operandum than vehicle dams. On postnatal day (P) 6, cannabis-exposed offspring made more total calls in the isolation-induced ultrasonic vocalization task of emotional reactivity. This effect on emotional reactivity was age-dependent, as it did not reappear on P10 or P13. In adulthood, there were no differences between prenatal treatment groups in the elevated plus maze and novelty suppressed feeding tasks of anxiety-like behavior. Adult cannabis-exposed offspring also displayed sex-dependent effects on cannabis-seeking behavior. Specifically, male cannabis-exposed rats earned fewer vapor deliveries and made fewer nosepokes to the active nosepoke regardless of their assigned vapor. Female cannabis-exposed rats generally showed similar cannabis-seeking behavior to their controls. Finally, no differences in parvalbumin interneuron number or distribution were detected. My dissertation indicates that prenatal cannabis exposure causes age- and sex-dependent effects on emotional reactivity and cannabis-seeking behavior, respectively. It also introduces a novel self-administration model that can be used to provide valuable information to parents, caregivers, and healthcare professionals about the risks associated with prenatal cannabis exposure.
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Details
- Title
- INVESTIGATING THE IMPACTS OF MATERNAL CANNABIS USE ON DEVELOPING OFFSPRING IN RATS
- Creators
- Halle Weimar
- Contributors
- Ryan J McLaughlin (Advisor)Samantha S Gizerian (Committee Member)Rita A Fuchs Lokensgard (Committee Member)Maria A Gartstein (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Program in Neuroscience
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 163
- Identifiers
- OCLC#: 1365772509; 99900901029801842
- Language
- English
- Resource Type
- Dissertation