Blood-Brain Barrier (BBB)
A selective semipermeable barrier formed by brain endothelial cells that restricts the passage of substances from blood to brain. Cannabinoids readily cross the BBB due to their lipophilicity.
In Depth
The BBB protects the brain from pathogens and toxins but also limits drug delivery to the CNS. Cannabinoids' high lipophilicity allows them to cross the BBB efficiently. 11-OH-THC (the active metabolite of oral THC) crosses the BBB more readily than THC itself, contributing to the more intense effects of oral cannabis. CBD also crosses the BBB and achieves meaningful brain concentrations. BBB disruption in neuroinflammatory conditions may alter cannabinoid CNS exposure.
Related Terms
More in Neuroscience
Retrograde Signaling
A form of synaptic communication where the postsynaptic neuron sends chemical signals back to the presynaptic neuron to modulate neurotransmitter release.
Neurogenesis
The process by which new neurons are formed in the brain. In adults, primarily occurs in the hippocampus (dentate gyrus) and olfactory bulb.
Neuroprotection
The preservation of neuronal structure and function against injury, degeneration, or disease.
Neuroinflammation
Inflammation of nervous tissue, involving activation of microglia and astrocytes and release of pro-inflammatory cytokines within the CNS.
Hippocampus
A brain region critical for memory formation, spatial navigation, and stress regulation. Highly enriched in CB1 receptors and particularly sensitive to cannabinoid effects.