TY - JOUR T1 - Low levels of muscarinic M1 receptor–positive neurons in cortical layers III and V in Brodmann areas 9 and 17 from individuals with schizophrenia JF - Journal of Psychiatry and Neuroscience JO - J Psychiatry Neurosci SP - 338 LP - 346 DO - 10.1503/jpn.170202 VL - 43 IS - 5 AU - Elizabeth Scarr AU - Shaun Hopper AU - Valentina Vos AU - Myoung Suk Seo AU - Ian Paul Everall AU - Timothy Douglas Aumann AU - Gursharan Chana AU - Brian Dean Y1 - 2018/09/01 UR - http://jpn.ca/content/43/5/338.abstract N2 - Background: Results of neuroimaging and postmortem studies suggest that people with schizophrenia may have lower levels of muscarinic M1 receptors (CHRM1) in the cortex, but not in the hippocampus or thalamus. Here, we use a novel immunohistochemical approach to better understand the likely cause of these low receptor levels.Methods: We determined the distribution and number of CHRM1-positive (CHRM1+) neurons in the cortex, medial dorsal nucleus of the thalamus and regions of the hippocampus from controls (n = 12, 12 and 5, respectively) and people with schizophrenia (n = 24, 24 and 13, respectively).Results: Compared with controls, levels of CHRM1+ neurons in people with schizophrenia were lower on pyramidal cells in layer III of Brodmann areas 9 (−44%) and 17 (−45%), and in layer V in Brodmann areas 9 (−45%) and 17 (−62%). We found no significant differences in the number of CHRM1+ neurons in the medial dorsal nucleus of the thalamus or in the hippocampus.Limitations: Although diagnostic cohort sizes were typical for this type of study, they were relatively small. As well, people with schizophrenia were treated with antipsychotic drugs before death.Conclusion: The loss of CHRM1+ pyramidal cells in the cortex of people with schizophrenia may underpin derangements in the cholinergic regulation of GABAergic activity in cortical layer III and in cortical/subcortical communication via pyramidal cells in layer V. ER -