The novel GTPase Rit differentially regulates axonal and dendritic growth.

The Rit GTPase is widely expressed in developing and adult nervous systems, and our previous data with pheochromocytoma cells implicate Rit signaling in NGF-induced neurite outgrowth. In this study, we investigated a role for Rit in neuronal morphogenesis. Expression of a dominant-negative (dn) Rit mutant in hippocampal neurons inhibited axonal growth but potentiated dendritic growth.

Forebrain ischemia increases GLUT1 protein in brain microvessels and parenchyma.

Glucose transport into nonneuronal brain cells uses differently glycosylated forms of the glucose transport protein, GLUT1. Microvascular GLUT1 is readily seen on immunocytochemistry, although its parenchymal localization has been difficult. Following ischemia, GLUT1 mRNA increases, but whether GLUT1 protein also changes is uncertain.

Neurotrophins and the neuroendocrine brain: different neurotrophins sustain anatomically and functionally segregated subsets of hypothalamic dopaminergic neurons.

Hypothalamic neurons control a variety of important hormonal and behavioral functions. Little is known, however, about the neurotrophic factors that these neurons may require for survival and/or maintenance of their differentiated functions. We conducted experiments to examine this issue, utilizing a combination of immunohistochemical, in situ hybridization and cell culture approaches.

Progressive hippocampal loss of immunoreactive GLUT3, the neuron-specific glucose transporter, after global forebrain ischemia in the rat.

Brain damage after global forebrain ischemia is worsened by prior hyperglycemia and ameliorated by antecedent hypoglycemia. To assess whether GLUT3, the neuron specific glucose transporter and its mRNA, are affected by cerebral ischemia, we investigated the hippocampal pattern of GLUT3 immunoreactivity and GLUT3 gene expression 1, 4 and 7 days after global forebrain ischemia in a rat 2-vessel occlusion model. We used a newly generated, specific, C-terminally directed polyclonal antiserum against GLUT3 to stain coronal frozen sections.

Immunohistochemical localization of the neuron-specific glucose transporter (GLUT3) to neuropil in adult rat brain.

The precise histologic localization of GLUT3, a glucose transporter thought to be restricted to neurons, is unknown. Using a high-affinity, specific antiserum against rodent GLUT3 for immunocytochemistry, light microscopic staining concentrates heterogeneously in the neuropil in a region- and lamina-specific manner; intense staining characterizes areas with high rates of glucose utilization such as inferior colliculus and pyriform cortex. Neuropil localization with little perikaryal staining suggests that GLUT3 may provide the energy needed locally for synaptic transmission.