Effect of maternal delta 9-tetrahydrocannabinol on developing serotonergic system

Area of Science:

• Neuroscience
• Developmental Biology
• Pharmacology

Background:

• The serotonergic system is crucial for neurodevelopment.
• Cannabinoids, like delta-9-tetrahydrocannabinol (THC), can cross the placenta.
• Understanding perinatal cannabinoid exposure effects is vital for public health.

Purpose of the Study:

• To investigate the impact of maternal delta-9-tetrahydrocannabinol (THC) exposure on the developing serotonergic system in offspring.
• To determine if THC exposure alters indolamine levels in specific brain regions.
• To explore sex-specific differences in response to perinatal THC exposure.

Main Methods:

• Pregnant rats received daily oral doses of delta-9-tetrahydrocannabinol (5 mg/kg) from gestational day 5 to postnatal day 1.
• Indolamine levels, including serotonin (5-HT), were quantified in four brain areas of the offspring.
• Measurements were taken on the day before or after birth to assess perinatal changes.

Main Results:

• Offspring indolamine levels varied significantly based on brain area, sex, and developmental stage (pre- or postnatal).
• Maternal THC exposure led to decreased diencephalic levels of 5-hydroxytryptamine (5-HT) in offspring.
• Male offspring exhibited greater susceptibility to these serotonin level reductions compared to females.

Conclusions:

• Perinatal exposure to delta-9-tetrahydrocannabinol alters key neurotransmitter systems during critical developmental windows.
• Observed decreases in 5-HT levels, particularly in males, may underlie long-term neurophysiological consequences of cannabinoid exposure.
• These findings highlight potential risks associated with maternal cannabinoid use during pregnancy.