Glutamate receptors in human caudate nucleus in normal aging and Alzheimer's disease

Neostriatum is one of the brain areas that are not primarily affected in Alzheimer's disease, according to classic regard of the disease. However, recent data emphasize the involvement of neostriatum, especially the head of the caudate nucleus, in the emergence of characteristic symptoms of the disease. Glutamatergic neurotransmission is a key component of striatal pathways. The present study is focused on glutamate receptors of striatal neurons on human caudate nucleus in normal aging and Alzheimer's disease. Immunohistochemical studies were carried out for N-methyl-D-aspartate receptor subunit 1 (NMDAR1), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit 2 (GluR2) and metabotropic glutamate receptor 5 (mGluR5). Ionotropic receptors (NMDAR1 and GluR2) were found to be expressed by 82% - 93% of striatal neurons with no significant alterations in aging and Alzheimer's disease. On the other hand, metabotropic receptor mGluR5 was found to be expressed by just 40% of striatal neurons in young individuals, with significant intensity variations among the neurons. This percent was increased in elderly individuals and Alzheimer's disease patients to 80% and 92% of striatal neurons, respectively. The up-regulation of mGluR5 both in normal aging and Alzheimer's disease is possibly associated with reorganization of neuronal connections, indicates the complexity of this receptor function and renders quite unpredictable the intervention and treatment of dementia with mGluR5 inhibitors or modulators. © 2013 Bentham Science Publishers

Distribution of SRPK1 in human brain

Extensive alternative splicing is observed in the mammalian nervous system providing for protein diversity and specificity to accomplish the complex neuronal functions. Mechanisms underlying neuron specific splicing are not yet well understood. Among the factors regulating splicing of major importance are serine/arginine protein kinases (SRPKs) that phosphorylate SR splicing factors. SRPK1 is known to be expressed in the mammalian central nervous system. The present immunohistochemical study reveals a region- and neuron-specific localization of SRPK1 in human brain. The potential involvement of the kinase in the regulation of alternative splicing of various neuronal proteins is discussed. © 2011 Elsevier B.V