PMID- 9083261
OWN - NLM
STAT- MEDLINE
DCOM- 19970416
LR  - 20200930
IS  - 0037-9727 (Print)
IS  - 0037-9727 (Linking)
VI  - 214
IP  - 3
DP  - 1997 Mar
TI  - Differences in intracellular CA2+ stores of submandibular cells of adult and 
      newborn rats.
PG  - 271-9
AB  - The intracellular Ca2+ stores of submandibular acinar cells of adult and newborn 
      rats were compared by measuring changes in cytosolic Ca2+ ([Ca2+]i) with the 
      Ca2+-sensitive fluorescent probe, fura-2, in intact cells and 45Ca2+ release in 
      permeabilized cells. In cells of adult rats, acetylcholine (ACh) and thapsigargin 
      (TG) elicited, respectively, a 105% and 125% net increase in [Ca2+]i in Ca2+-free 
      medium. In cells of newborn animals, the ACh-induced [Ca2+]i increase (218%) was 
      larger; but the TG-induced increase was significantly smaller (77%), suggesting 
      that the TG-sensitive Ca2+ pump of the store is less developed, abundant, or 
      responsive in these cells. After ACh or TG, ionomycin elicited a further Ca2+ 
      release. Ionomycin by itself completely discharged the ACh- and TG-sensitive 
      store in cells of mature glands but not in cells of immature glands, suggesting a 
      further difference in the distribution of the agonist and ionomycin sensitivities 
      in the two types of cells. After exposure to ACh + ionomycin or TG + ionomycin, 
      collapsing the intracellular pH gradient with monensin caused a third and large 
      Ca2+ release (262% and 289%, respectively) in cells of adult rats, but a 
      significantly smaller release (96%, P < 0.001, and 57%, P < 0.001, respectively) 
      in cells of newborn rats, suggesting that a third, IP3-insensitive acidic store 
      is significantly smaller in cells of immature glands. In permeabilized and 
      45Ca2+-loaded cells, inositol-1,4,5-trisphosphate (IP3, 5 microM) induced an 
      identical 45Ca2+ release (34% and 33%, respectively) in both types of cells, but 
      TG induced a significant smaller 45Ca2+ release in cells of immature glands (15%) 
      than in cells of mature glands (33%). Monensin discharged <10% of loaded 45Ca2+ 
      in both types of cells, indicating that the radiotracer was not loaded into the 
      monensin-sensitive store. These results suggest that in cells of immature glands: 
      (1) the TG-sensitive Ca2+ pump of the IP3-sensitive store is not well developed; 
      (ii) the IP3-sensitive store is not completely discharged by ionomycin; and (iii) 
      an acidic store likely to be associated with secretory granules is also 
      underdeveloped and of a smaller size than in cells of mature glands.
FAU - Martinez, J R
AU  - Martinez JR
AD  - Department of Pediatrics, University of Texas Health Science Center at San 
      Antonio, 78284, USA.
FAU - Wells, J
AU  - Wells J
FAU - Puente, S
AU  - Puente S
FAU - Willis, S
AU  - Willis S
FAU - Zhang, G H
AU  - Zhang GH
LA  - eng
GR  - DE04847/DE/NIDCR NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Proc Soc Exp Biol Med
JT  - Proceedings of the Society for Experimental Biology and Medicine. Society for 
      Experimental Biology and Medicine (New York, N.Y.)
JID - 7505892
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (Ionophores)
RN  - 56092-81-0 (Ionomycin)
RN  - 67526-95-8 (Thapsigargin)
RN  - 85166-31-0 (Inositol 1,4,5-Trisphosphate)
RN  - 906O0YJ6ZP (Monensin)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - N9YNS0M02X (Acetylcholine)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Acetylcholine/pharmacology
MH  - Age Factors
MH  - Animals
MH  - Animals, Newborn
MH  - Calcium/*metabolism
MH  - Calcium-Transporting ATPases/antagonists & inhibitors
MH  - Cells, Cultured
MH  - Enzyme Inhibitors/pharmacology
MH  - Inositol 1,4,5-Trisphosphate/pharmacology
MH  - Ionomycin/pharmacology
MH  - Ionophores/pharmacology
MH  - Male
MH  - Monensin/pharmacology
MH  - Rats
MH  - Submandibular Gland/*metabolism
MH  - Thapsigargin/pharmacology
EDAT- 1997/03/01 00:00
MHDA- 1997/03/01 00:01
CRDT- 1997/03/01 00:00
PHST- 1997/03/01 00:00 [pubmed]
PHST- 1997/03/01 00:01 [medline]
PHST- 1997/03/01 00:00 [entrez]
AID - 10.3181/00379727-214-44096 [doi]
PST - ppublish
SO  - Proc Soc Exp Biol Med. 1997 Mar;214(3):271-9. doi: 10.3181/00379727-214-44096.