# A New Model of Gestational Cannabis Exposure

> **NIH NIH R21** · UNIVERSITY OF MARYLAND BALTIMORE · 2022 · $193,125

## Abstract

Summary
The use of cannabis during pregnancy have dramatically increased during the last ten years.
While the effects of cannabis and its components on brain development are poorly known,
recent studies have observed frequent mental health problems in the offspring of mothers that
used marijuana during gestation. During the third trimester of human gestation the brain
undergoes a “growth spurt” that is characterized by an intensive process of synaptogenesis.
This stage is followed by a period of refinement by activity-dependent neuronal plasticity where
synapses reaching “correct targets” are strengthened whereas synapses reaching “incorrect
targets” are pruned. The exposure to drugs and certain medications during this period have the
potential to alter these processes, resulting in multiple neurobehavioral problems. It has been
demonstrated in humans and animal models that developmental THC exposure reduces the
expression of CB1r. In layer 2/3 of the visual cortex endocannabinoid neurotransmission is
essential for the expression of iLTD and for the developmental transition between high to low
GABA release probability characteristic of mature inhibitory cells in this region. Proper levels of
inhibition are essential for the ocular dominance plasticity and the establishment of neuronal
circuits responsible for neuronal orientation tuning and formation of orientation selectivity
columns. Based on this scientific premise we hypothesize that THC exposure during the third
trimester equivalent of human gestation leads to persistent reduction in endocannabinoid
transmission, resulting in an impairment in iLTD and preventing maturation of inhibition. As a
consequence, both ocular dominance plasticity and orientation selectivity would be impaired.
Here we will use a combination of in vivo and ex vivo electrophysiology and optical imaging of
intrinsic signals to test this hypothesis. The accomplishment of these experiments would result
in the development of a novel model of prenatal exposure to cannabis that could be used to
investigate mechanisms of action of gestational marijuana and potential interventions.

## Key facts

- **NIH application ID:** 10447141
- **Project number:** 5R21DA053566-02
- **Recipient organization:** UNIVERSITY OF MARYLAND BALTIMORE
- **Principal Investigator:** Alexandre Esteves Medina
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $193,125
- **Award type:** 5
- **Project period:** 2021-07-15 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10447141

## Citation

> US National Institutes of Health, RePORTER application 10447141, A New Model of Gestational Cannabis Exposure (5R21DA053566-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10447141. Licensed CC0.

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