| 11874555 |
Vanden Berghe P, Missiaen L, Janssens J, Tack J: Calcium signalling and removal mechanisms in myenteric neurones. Neurogastroenterol Motil. 2002 Feb;14(1):63-73.
To characterize further the Ca2+ signalling mechanisms of myenteric neurones, we studied the effect of thapsigargin, a blocker of the Ca2+-store ATPase, and the mechanisms involved in restoring the intracellular Ca2+ concentration ([Ca2+] i) after activation. Thapsigargin (5 x 10 (-6) mol L (-1)) induced an oscillatory [Ca2+] i response in 86.6% of the neurones (n=276), which was blocked by the removal of extracellular Ca2+ and by omega-conotoxin MVIIA (5 x 10 (-7) mol L (-1)). The IP3-blocker, 2-aminoethyl-diphenyl-borate (75 x 10 (-6) mol L (-1)), blocked or reduced the responses in 74.5% of the neurones. The oscillatory responses induced by the depletion of Ca2+ stores suggest that myenteric neurones might recruite N-type Ca2+ channels as a refill mechanism. Thapsigargin pretreatment increased the amplitude, the upstroke and duration of the K+-induced [Ca2+] i responses. Mitochondrial blockers (rotenone and antimycin/oligomycin) also prolonged the responses, but without affecting the amplitude. Furthermore, it was found that for high [Ca2+] i, the thapsigargin-sensitive Ca2+ uptake was crucial, while mitochondrial blockade affected the Ca2+ uptake over a wide range of concentrations. The Ca2+-sequestering components might also have been compensating for each other, as most drugs only delayed and not inhibited Ca2+ removal. |
1(0,0,0,1) |