Citations

Recent studies have demonstrated that the function of glia is not restricted to the support of neuronal function. Especially, astrocytes are essential for neuronal activity in the brain. Astrocytes actively participate in synapse formation and brain information processing by releasing or uptaking gliotransmitters such as glutamate, d ‐serine, adenosine 5′‐triphosphate ( ATP ), and adenosine. In the central nervous system, adenosine plays an important role in regulating neuronal activity as well as in controlling other neurotransmitter systems such as GABA , glutamate, and dopamine. Ethanol ( E t OH ) increases extracellular adenosine levels, which regulates the ataxic and hypnotic/sedative (somnogenic) effects of E t OH . Adenosine signaling is also involved in the homeostasis of major inhibitory/excitatory neurotransmission (i.e., GABA or glutamate) through neuron–glial interactions, which regulates the effect of E t OH and sleep. Adenosine transporters or astrocytic SNARE ‐mediated transmitter release regulates extracellular or synaptic adenosine levels. Adenosine then exerts its function through several adenosine receptors and regulates glutamate levels in the brain. This review presents novel findings on how neuron–glial interactions, particularly adenosinergic signaling and glutamate uptake activity involving glutamate transporter 1 ( GLT 1), are implicated in alcoholism and sleep disorders.

ABSTRACTObjectives:Abnormal gastric accommodation to a meal results in dyspepsia. Current methods to measure gastric volume (GV) are invasive or involve ionizing radiation. The aims of this study were to compare fasting and postprandial (PP) GVs measured by 99mTc‐single photon emission computed tomography (SPECT) and 3‐dimensional ultrasound (3D‐US) in adults, to assess the performance characteristics of 3D‐US measurement of GV during fasting and postprandially, and to develop normative data of GVs in 24 healthy adolescents.Patients and Methods:Eleven adults underwent SPECT and 3D‐US simultaneously to measure GV, and a second 3D‐US alone within 1 week of the first study. Twenty‐four adolescents underwent 1 3D‐US measurement. Each study included fasting, a 300‐mL Ensure meal, and 0 to 30‐minute PP GV measurements.Results:3D‐US identifies GV accommodation to 300 mL Ensure. Delta (0–30 minutes average PP fasting) GV was 444 mL (median, interquartile range [IQR] = 422, 534) for 3D‐US and 543 mL (median, IQR = 486, 564) for SPECT (P = 0.15). There were larger interindividual coefficients of variation for GV by 3D‐US (60.3% fasting and 21.3% average PP) compared with 19% fasting and 9.2% PP for SPECT. Intraindividual coefficients of variation for the 2 3D‐US measurements in adults were 84% fasting and 44% average PP. The estimated GVs for the adolescent group (median [25th–75th IQR]) were 33 (18–53) mL fasting, 330 (284–357) mL 30 minutes PP, and 281 (240–324) mL for delta GV.Conclusions:3D‐US is a promising method to measure GV accommodation to a meal. Large coefficients of variation reflect the learning stage in development of this promising technique.