Bradley J. Segura

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Enteric glia are important participants in information processing in the enteric nervous system. However, intercellular signaling mechanisms in enteric glia remain largely unknown. We postulated that intercellular calcium waves exist in enteric glia. Primary cultures of enteric glia were isolated from neonatal guinea pig taenia coli. Intracellular calcium(More)
Protease-activated receptors (PARs) belong to the family of membrane receptors coupled to G-proteins; their presence is reported in a wide variety of cells. The object of this study was to demonstrate the presence of PAR-1 and PAR-2 in myenteric glia of the guinea pig, and to elucidate the cellular mechanisms that are triggered upon receptor activation.(More)
Cocaine- and amphetamine-regulated transcript (CART) peptide is a recently described neuropeptide that has been localized to areas of the central and peripheral nervous systems. CART has been shown to be involved in feeding behavior when injected centrally, however, its effects upon peripheral tissues have not been studied. This report describes the effects(More)
The responsiveness of cultured myenteric neurons to cholecystokinin (CCK-8) was examined using fura-2-based digital microfluorimetric measurement of intracellular calcium ([Ca(2+)](i)). CCK-8 (10(-10)-10(-6)M) evoked concentration-dependent increases in percentage of neurons responding (8-52%) and delta[Ca(2+)](i) (76-169 nM). Gastrin (1 microM) also(More)
In myenteric neurons two different receptor subtypes govern the intracellular Ca(2+) stores: the inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R) and the ryanodine receptor (RyR). Their degree of functional overlap was determined by examining Ca(2+) release in these cells through both superfusion techniques and intracellular microinjection.(More)
Sphingosine-1-phosphate (S1P) caused dose-dependent and time-dependent increases in c-fos mRNA. Pretreatment with pertussis toxin (PTX; 100 ng/mlx24 h) reduced c-fos activation by S1P (100 microM-187+/-6% vs. 411+/-27%) and lysophosphatidic acid (LPA; 100 microM-90+/-34% vs. 188+/-41%), but not by sphingosylphosphorylcholine (SPC; 100 microM-390+/-47% vs.(More)
Capacitative calcium entry (CCE) is the process by which intracellular calcium is replenished from the external milieu upon depletion of intracellular stores. CCE is thought to participate in chemotaxis, proliferation and cell signalling. A physical interaction between intracellular stores and the plasma membrane is postulated to regulate CCE. We(More)
The enteric nervous system plays an integral role in the gastrointestinal tract. Within this intricate network, enteric glia are crucial in the maintenance of normal bowel function, yet their signaling mechanisms are poorly understood. Enteric glia, and not enteric neurons, selectively responded to lysophosphatidic acid (LPA), a product of(More)
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