| Author/Editor | Komori, Yoko; Tanaka, Megumi; Kuba, Motoko; Ishii, Masahiro; Abe, Maiko; Kitamura, Naoki; Verkhratsky, Alexei; Shibuya, Izumi; Dayanithi, Govindan | |
| Title | Ca[sup]2+ homeostasis, Ca[sup]2+ signalling and somatodendritic vasopressin release in adult rat supraoptic nucleus neurones | |
| Type | članek | |
| Vol. and No. | Letnik 48, št. 6 | |
| Publication year | 2010 | |
| Volume | str. 324-332 | |
| ISSN | 0143-4160 - Cell calcium | |
| Language | eng | |
| Abstract | Multiple mechanisms that maintain Ca 2+ homeostasis and provide for Ca 2+ signalling operate in the somatas and neurohypophysial nerve terminals of supraoptic nucleus (SON) neurones. Here, we exam- ined the Ca 2+ clearance mechanisms of SON neurones from adult rats by monitoring the effects of the selective inhibition of different Ca 2+ homeostatic molecules on cytosolic Ca 2+ ([Ca 2+ ] i ) transients in iso- latedSONneurones. Inaddition,wemeasuredsomatodendriticvasopressin(AVP)releasefromintactSON tissueinanattempttocorrelateitwith[Ca 2+ ] i dynamics. WhenbathingthecellsinaNa + -freeextracellular solution, thapsigargin, cyclopiazonic acid (CPA), carbonyl cyanide 3-chlorophenylhydrazone (CCCP), and the inhibitor of plasma membrane Ca 2+ -ATPase (PMCA), La 3+ , all significantly slowed down the recovery of depolarisation (50mM KCl)-induced [Ca 2+ ] i transients. The release of AVP was stimulated by 50mM KCl, and the decline in the peptide release was slowed by Ca 2+ transport inhibitors. In contrast to previous reports, our results show that in the fully mature adult rats: (i) all four Ca 2+ homeostatic pathways, the Na + /Ca 2+ exchanger, the endoplasmic reticulum Ca 2+ pump, the plasmalemmal Ca 2+ pump and mitochon- dria, are complementary in actively clearing Ca 2+ from SON neurones; (ii) somatodendritic AVP release closely correlates with intracellular [Ca 2+ ] i dynamics; (iii) there is (are) Ca 2+ clearance mechanism(s) dis- tinct from the four outlined above; and (iv) Ca 2+ homeostatic systems in the somatas of SON neurones differ from those expressed in their terminals. | |
| Keywords | hypothalamus cell bodies nerve terminals neuropeptides Ca2+ signalling Ca2+ clearance Ca2+ stores mitochondria Na + /Ca 2+ exchangers plasma membrane endoplasmic reticulum calcium pumps transgenic rats stimulus-secretion coupling |