Table 1.
Reference | Schizophrenia Cohort [n] | Technique | Finding in Schizophrenia Subjects |
---|---|---|---|
Cerebrospinal fluid | |||
(1) | first-episode, antipsychotic-naive [47] | HPLC/MS | elevated CSF anandamide levels |
(2) | prodromal psychosis [27] | HPLC/MS | elevated CSF anandamide levels |
(3) | [10] | HPLC/MS | elevated CSF anandamide levels |
Blood | |||
(4) | acute symptoms, off antipsychotics [12] | LC-APCI-MS | elevated blood anandamide levels |
Imaging studies | |||
(5) | [9] | PET [11C]-OMAR | elevated CB1R binding in all brain regions, significant in pons |
Postmortem brain studies | |||
Endocannabinoid enzymes | |||
(6) | [42] | qPCR | no change in mRNA levels for endocannabinoid synthesizing (DAGL) and metabolizing (MGL, FAAH) enzymes in PFC area 9 |
(7) | [42] | qPCR | elevated mRNA levels for 2-AG metabolizing enzyme ABHD6 in PFC area 9 of younger subjects; no changes in antipsychotic- or THC-exposed monkeys |
CB1R mRNA and protein | |||
(8) | [23] | in situ hybridization, immunocytochemistry | lower CB1R mRNA and protein levels in PFC area 9; no change in antipsychotic-exposed monkeys |
(9) | [26] | immunocytochemistry | lower CB1R immunoreactivity in PFC area 46, no change in depression |
(10) | [37] | qPCR | no change in CB1R mRNA levels in PFC area 46 |
(11) | [31] | qPCR | no change in CB1R mRNA levels in PFC area 9 |
CB1R autoradiography | |||
(12) | [14] | CB1R agonist [3H]-CP55940 | elevated CB1R binding in PFC area 9, but not hippocampus, caudate, or putamen |
(10) | [37] | [3H]-CP55940 | elevated CB1R binding in PFC area 46 in paranoid subjects |
(13) | [47] | CB1R inverse agonist [3H]-MePPEP | elevated CB1R binding in PFC areas 9 and 46 |
(14) | [10] | CB1R antagonist [3H]-SR141716 | elevated CB1R binding in anterior cingulate cortex |
(15) | [8] | [3H]-CP55940 | elevated CB1R binding in superficial layers of posterior cingulate cortex |
(16) | [21] | [3H]-OMAR | elevated CB1R binding in PFC area 9 in same schizophrenia subjects with lower CB1R mRNA and protein levels (8) |
Abbreviations: 2-AG: 2-arachidonoylglyercol; ABHD6: α-β-hydrolase domain 6; CB1R: CB1 receptor: CSF: cerebrospinal fluid; DAGL: diacylglyercol lipase; FAAH; fatty acid amide hydrolase; HPLC/MS: high performance liquid chromatography / mass spectrometry; LC-APCI-MS: liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry; MGL: monoglyceride lipase; PET: positron emission tomography; PFC: prefrontal cortex; qPCR: quantitative polymerase chain reaction; THC: tetrahydrocannabinol