Mobilization of intracellular calcium by substance p in a human astrocytoma cell line (U-373 MG)

✍ Scribed by A. Bordey; P. Feltz; J. Trouslard

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 629 KB
• Volume: 11
• Category: Article
• ISSN: 0894-1491
• DOI: 10.1002/glia.440110309

✦ Synopsis

Variations in intracellular free calcium concentration (A1Cazfli) were measured in intact and isolated human astrocytoma cells (U373 MG) loaded with fura-2 acetoxymethylester. Microperfusion of 50 nM substance P (SP), applied for 1 s, increased [Ca" ' Ii by 351 nM from a stable basal level of [Ca2+li of 26 nM. The peak A[Ca2'li induced by SP was dose dependent with a threshold of nM, an ED,, of 1.3 nM and a maximal effect for concentrations of SP greater than 100 nM. The NK1 receptor agonist, [Sar9Met(02)11]SP, mimicked the effect of SP, while the NK2 and NK3 selective receptor agonists, [N110]NKA(4-10) and senktide, respectively, had no effect. The h[Ca2+Ii induced by SP was unaffected by 100 pM cadmium or by removal of extracellular calcium ions. Caffeine up to 30 mM had no effect on [Ca" ' Ji. In contrast, thapsigargin increased resting [Ca2+Ii by 92 nM and reduced the A[Ca2'Ii induced by SP. A pertussis treatment (500 ng/ml-24 h) did not modify the A[Ca2+], induced by SP.

We conclude that SP, acting on a NK1 receptor, mobilizes cytosolic calcium from an intracellular calcium pool which can be partially depleted by thapsigargin.