Mechanisms of cannabidiol neuroprotection in hypoxic-ischemic newborn pigs: role of 5HT(1A) and CB2 receptors

Neuropharmacology. 2013 Aug;71:282-91. doi: 10.1016/j.neuropharm.2013.03.027. Epub 2013 Apr 12.

Abstract

The mechanisms underlying the neuroprotective effects of cannabidiol (CBD) were studied in vivo using a hypoxic-ischemic (HI) brain injury model in newborn pigs. One- to two-day-old piglets were exposed to HI for 30 min by interrupting carotid blood flow and reducing the fraction of inspired oxygen to 10%. Thirty minutes after HI, the piglets were treated with vehicle (HV) or 1 mg/kg CBD, alone (HC) or in combination with 1 mg/kg of a CB₂ receptor antagonist (AM630) or a serotonin 5HT(1A) receptor antagonist (WAY100635). HI decreased the number of viable neurons and affected the amplitude-integrated EEG background activity as well as different prognostic proton-magnetic-resonance-spectroscopy (H(±)-MRS)-detectable biomarkers (lactate/N-acetylaspartate and N-acetylaspartate/choline ratios). HI brain damage was also associated with increases in excitotoxicity (increased glutamate/N-acetylaspartate ratio), oxidative stress (decreased glutathione/creatine ratio and increased protein carbonylation) and inflammation (increased brain IL-1 levels). CBD administration after HI prevented all these alterations, although this CBD-mediated neuroprotection was reversed by co-administration of either WAY100635 or AM630, suggesting the involvement of CB₂ and 5HT(1A) receptors. The involvement of CB₂ receptors was not dependent on a CBD-mediated increase in endocannabinoids. Finally, bioluminescence resonance energy transfer studies indicated that CB₂ and 5HT(1A) receptors may form heteromers in living HEK-293T cells. In conclusion, our findings demonstrate that CBD exerts robust neuroprotective effects in vivo in HI piglets, modulating excitotoxicity, oxidative stress and inflammation, and that both CB₂ and 5HT(1A) receptors are implicated in these effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Brain / drug effects
  • Brain / immunology
  • Brain / metabolism
  • Brain / pathology
  • Brain Injuries / physiopathology
  • Cannabidiol / antagonists & inhibitors
  • Cannabidiol / pharmacokinetics
  • Cannabidiol / pharmacology
  • Cannabidiol / therapeutic use*
  • Cannabinoid Receptor Antagonists / pharmacology
  • Cannabinoids / metabolism
  • Cannabinoids / pharmacokinetics
  • Cannabinoids / therapeutic use
  • Disease Models, Animal*
  • HEK293 Cells
  • Humans
  • Hypoxia-Ischemia, Brain / drug therapy*
  • Hypoxia-Ischemia, Brain / etiology
  • Hypoxia-Ischemia, Brain / metabolism
  • Hypoxia-Ischemia, Brain / pathology
  • Male
  • Nerve Tissue Proteins / antagonists & inhibitors
  • Nerve Tissue Proteins / metabolism
  • Neurons / drug effects
  • Neurons / immunology
  • Neurons / metabolism
  • Neurons / pathology
  • Neuroprotective Agents / antagonists & inhibitors
  • Neuroprotective Agents / pharmacokinetics
  • Neuroprotective Agents / pharmacology
  • Neuroprotective Agents / therapeutic use*
  • Protein Multimerization
  • Random Allocation
  • Receptor, Cannabinoid, CB2 / antagonists & inhibitors
  • Receptor, Cannabinoid, CB2 / genetics
  • Receptor, Cannabinoid, CB2 / metabolism*
  • Receptor, Serotonin, 5-HT1A / chemistry
  • Receptor, Serotonin, 5-HT1A / genetics
  • Receptor, Serotonin, 5-HT1A / metabolism*
  • Recombinant Fusion Proteins / metabolism
  • Reperfusion Injury / prevention & control*
  • Serotonin 5-HT1 Receptor Antagonists / pharmacology
  • Sus scrofa

Substances

  • Cannabinoid Receptor Antagonists
  • Cannabinoids
  • Nerve Tissue Proteins
  • Neuroprotective Agents
  • Receptor, Cannabinoid, CB2
  • Recombinant Fusion Proteins
  • Serotonin 5-HT1 Receptor Antagonists
  • Receptor, Serotonin, 5-HT1A
  • Cannabidiol