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Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now recognized that neurotransmitter-mediated signalling has a key(More)
Calcium signalling in astrocytes couples changes in neural activity to alterations in cerebral blood flow by eliciting vasoconstriction or vasodilation of arterioles. However, the mechanism for how these opposite astrocyte influences provide appropriate changes in vessel tone within an environment that has dynamic metabolic requirements remains unclear.(More)
Cerebral blood flow (CBF) is coupled to neuronal activity and is imaged in vivo to map brain activation. CBF is also modified by afferent projection fibres that release vasoactive neurotransmitters in the perivascular region, principally on the astrocyte endfeet that outline cerebral blood vessels. However, the role of astrocytes in the regulation of(More)
The "toxin-resistant" R-type Ca2+ channels are expressed widely in the CNS and distributed mainly in apical dendrites and spines. They play important roles in regulating signal transduction and intrinsic properties of neurons, but the modulation of these channels in the mammalian CNS has not been studied. In this study we used whole-cell patch-clamp(More)
Neuronal excitotoxicity during stroke is caused by activation of unidentified large-conductance channels, leading to swelling and calcium dysregulation. We show that ischemic-like conditions [O(2)/glucose deprivation (OGD)] open hemichannels, or half gap junctions, in neurons. Hemichannel opening was indicated by a large linear current and flux across the(More)
Most magnocellular neurosecretory cells that terminate in the posterior pituitary secrete either vasopressin, oxytocin, or enkephalin. Intracellular injection of the fluorescent dye Lucifer Yellow into single magnocellular neurons in slices of rat hypothalamus resulted in dye transfer between these cells. Freeze-fracture replicas of these cells occasionally(More)
P2X(7) receptor subunits form homomeric ATP-gated, calcium-permeable cation channels. In this study, we used Western blots and immunocytochemistry to demonstrate that P2X(7) receptors are abundant on presynaptic terminals of mossy fiber synapses in the rat hippocampus. P2X(7)-immunoreactive protein was detected using a specific P2X(7) antibody in Western(More)
ATP release from astrocytes contributes to calcium ([Ca(2+)]) wave propagation and may modulate neuronal excitability. In epithelial cells and hepatocytes, cell swelling causes ATP release, which leads to the activation of a volume-sensitive Cl(-) current (I(Cl,swell)) through an autocrine pathway involving purinergic receptors. Astrocyte swelling is(More)
The control of cerebral vessel diameter is of fundamental importance in maintaining healthy brain function because it is critical to match cerebral blood flow (CBF) to the metabolic demand of active neurons. Recent studies have shown that astrocytes are critical players in the regulation of cerebral blood vessel diameter and that there are several molecular(More)
Imaging analysis techniques were used to examine changes in the intrinsic optical properties in hippocampal brain slices that occurred during synaptic activity evoked by Schaffer collateral stimulation in CA1. Repetitive synaptic activity was associated with an increase in light transmission in the synaptic region in stratum radiatum. The effect was seen at(More)