Whisker-evoked neurovascular coupling is preserved during hypoglycemia in mouse cortical arterioles and capillaries.

Hypoglycemia is a serious complication of insulin treatment of diabetes that can lead to coma and death. Neurovascular coupling, which mediates increased local blood flow in response to neuronal activity, increases glucose availability to active neurons. This mechanism could be essential for neuronal health during hypoglycemia, when total glucose supplies are low.

Astrocyte regulation of cerebral blood flow during hypoglycemia.

Hypoglycemia triggers increases in cerebral blood flow (CBF), augmenting glucose supply to the brain. We have tested whether astrocytes, which can regulate vessel tone, contribute to this CBF increase. We hypothesized that hypoglycemia-induced adenosine signaling acts to increase astrocyte Ca activity, which then causes the release of prostaglandins (PGs) and epoxyeicosatrienoic acids (EETs), leading to the dilation of brain arterioles and blood flow increases.

Dilation of cortical capillaries is not related to astrocyte calcium signaling.

The brain requires an adequate supply of oxygen and nutrients to maintain proper function as neuronal activity varies. This is achieved, in part, through neurovascular coupling mechanisms that mediate local increases in blood flow through the dilation of arterioles and capillaries. The role of astrocytes in mediating this functional hyperemia response is controversial.

Spatial Organization and Dynamics of the Extracellular Space in the Mouse Retina.

The extracellular space (ECS) plays an important role in the physiology of neural circuits. Despite our detailed understanding of the cellular architecture of the mammalian retina, little is known about the organization and dynamics of the retinal ECS. We developed an optical technique based on two-photon imaging of fluorescently labeled extracellular fluid to measure the ECS volume fraction (α) in the retina of male and female mice.

Cortical spreading depolarizations induced by surgical field blood in a mouse model of neurosurgery.

Objective: Cortical spreading depolarization (CSD) has been linked to poor clinical outcomes in the setting of traumatic brain injury, malignant stroke, and subarachnoid hemorrhage. There is evidence that electrocautery during neurosurgical procedures can also evoke CSD waves in the brain. It is unknown whether blood contacting the cortical surface during surgical bleeding affects the frequency of spontaneous or surgery-induced CSDs.

Role of PEPT2 in glycylsarcosine transport in astrocyte and glioma cultures.

The aims of the current study were (1) to quantify the role of PEPT2 in the uptake of glycylsarcosine (GlySar) in cultured neonatal astrocytes and (2) to examine GlySar transport and PEPT2 expression in two glioma cell lines. The uptake of [(14)C]GlySar was measured in astrocytes cultured from neonatal mouse (PEPT2(+/+) and PEPT2(-/-)) and rat, as well as rat C6 and F98 glioma cells. PEPT2 expression was examined by reverse transcription-polymerase chain reaction (RT-PCR).