Colocalization of integrir dendritic spine postsynal nonhuman primate corte

The expression of telencephalic reelin (Rein) and glutamic decarboxylase mRNAs and their respective cognate proteir down-regulated in postmortem brains of schizophrenia and b lar disorder patients. To interpret the pathophysiological sig cance of this finding, immunoelectron microscopic experiment! required, but these cannot be carried out in postmortem hu brains. As an alternative, we carried out such experiments in cortex of rats and nonhuman primates. We found that Re expressed predominantly in layer I of both cortices and is local to bitufted (double-bouquet), horizontal, and multipolar ynobutyric acid-ergic interneurons, which secrete Rein into e: cellular matrix. Rein secretion is mediated by a constitutive m anism that depends on the expression of a specific signal pep present in the Rein carboxy-terminal domain. Extracellular ma Rein is found to aggregate in proximity of postsynaptic dens expressed in apical dendrite spines, which include also thsubunit of integrin receptors. Most pyramidal neurons of var cortical layers express the mouse-disabled 1 (Dab1) protein, wI after phosphorylation by a soluble tyrosine kinase, functions a adapter protein, probably mediating a modulation of cytoskela protein expression. We hypothesize that the decrease of neul and dendritic spine density reported to exist in the neocorte psychiatric patients may be related to a down-regulation of R integrin interactions and the consequent decrease of cytoskeli protein turnover.