title: Mechanisms of cannabidiol neuroprotection in hypoxic-ischemic newborn pigs: role of 5HT(1A) and CB2 receptors.
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.
authors.affiliation: Experimental Unit, Pediatric Department, University Hospital Puerta de Hierro Majadahonda, 28222 Madrid, Spain.
authors.forename: M Ruth
authors.initials: MR
authors.lastname: Pazos
authors.forename: Nagat
authors.initials: N
authors.lastname: Mohammed
authors.forename: Hector
authors.initials: H
authors.lastname: Lafuente
authors.forename: Martin
authors.initials: M
authors.lastname: Santos
authors.forename: Eva
authors.initials: E
authors.lastname: Martínez-Pinilla
authors.forename: Estefania
authors.initials: E
authors.lastname: Moreno
authors.forename: Elsa
authors.initials: E
authors.lastname: Valdizan
authors.forename: Julián
authors.initials: J
authors.lastname: Romero
authors.forename: Angel
authors.initials: A
authors.lastname: Pazos
authors.forename: Rafael
authors.initials: R
authors.lastname: Franco
authors.forename: Cecilia J
authors.initials: CJ
authors.lastname: Hillard
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Alvarez
authors.forename: Jose
authors.initials: J
authors.lastname: Martínez-Orgado
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000187:drug effects / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D001930:Brain Injuries / Q000503:physiopathology; D002185:Cannabidiol / Q000037:antagonists & inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D063387:Cannabinoid Receptor Antagonists / Q000494:pharmacology; D002186:Cannabinoids / Q000378:metabolism / Q000493:pharmacokinetics / Q000627:therapeutic use; D004195:Disease Models, Animal; D057809:HEK293 Cells; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D008297:Male; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000037:antagonists & inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D055503:Protein Multimerization; D011897:Random Allocation; D043885:Receptor, Cannabinoid, CB2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D044282:Receptor, Serotonin, 5-HT1A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015427:Reperfusion Injury / Q000517:prevention & control*; D058829:Serotonin 5-HT1 Receptor Antagonists / Q000494:pharmacology; D034421:Sus scrofa
chemical_list: D063387:Cannabinoid Receptor Antagonists; D002186:Cannabinoids; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D043885:Receptor, Cannabinoid, CB2; D011993:Recombinant Fusion Proteins; D058829:Serotonin 5-HT1 Receptor Antagonists; D044282:Receptor, Serotonin, 5-HT1A; D002185:Cannabidiol