PMID- 8072853
OWN - NLM
STAT- MEDLINE
DCOM- 19940926
LR  - 20191210
IS  - 0031-6768 (Print)
IS  - 0031-6768 (Linking)
VI  - 427
IP  - 3-4
DP  - 1994 Jun
TI  - The thapsigargin-evoked increase in [Ca2+]i involves an InsP3-dependent Ca2+ 
      release process in pancreatic acinar cells.
PG  - 325-31
AB  - In pancreatic acinar cells, as in many other cell types, the tumour promoter 
      thapsigargin (TG) evokes a significant increase of intracellular free Ca2+ 
      ([Ca2+]i). The increases of [Ca2+]i evoked by TG was associated with significant 
      changes of plasma membrane Ca2+ permeability, with [Ca2+]i values following 
      changes in extracellular [Ca2+]. Plasma membrane Ca2+ extrusion is activated 
      rapidly as a consequence of the rise in [Ca2+]i evoked by TG and the rate of 
      extrusion is linearly dependent on [Ca2+]i up to 1 microM Ca2+. In contrast, the 
      activation of the Ca2+ entry pathway is delayed and the apparent rate of Ca2+ 
      entry is independent of [Ca2+]i. In the presence of 20 mM caffeine, which reduces 
      the resting levels of inositol trisphosphate (InsP3), the increase of [Ca2+]i 
      evoked by TG was significantly reduced. The reduction was manifest both as a 
      decrease of the amplitude of the [Ca2+]i peak (30% reduction) and, more 
      importantly, as a reduction of the apparent maximal rate of [Ca2+]i increase 
      (from 12.3 +/- 1.0 to 6.1 +/- 0.6 nM Ca2+/s). The inhibition evoked by caffeine 
      was reversible and the removal of caffeine in the continuous presence of TG 
      evoked a further increase of [Ca2+]i. The amplitude of the [Ca2+]i increase upon 
      caffeine removal was reduced as a function of the time of TG exposure. Addition 
      of TG in the presence of 1 mM La3+, which is known to inhibit the plasma membrane 
      Ca(2+)-activated adenosine triphosphatase, induced a much higher peak of [Ca2+]i. 
      This increase was associated with an augmentation of the apparent rate of [Ca2+]i 
      increase (from 12.3 +/- 1.2 to 16.1 +/- 1.9 nM Ca2+/s).(ABSTRACT TRUNCATED AT 250 
      WORDS)
FAU - Toescu, E C
AU  - Toescu EC
AD  - Physiological Laboratory, Liverpool University, Merseyside, UK.
FAU - Petersen, O H
AU  - Petersen OH
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Germany
TA  - Pflugers Arch
JT  - Pflugers Archiv : European journal of physiology
JID - 0154720
RN  - 0 (Terpenes)
RN  - 3G6A5W338E (Caffeine)
RN  - 67526-95-8 (Thapsigargin)
RN  - 6I3K30563S (Lanthanum)
RN  - 85166-31-0 (Inositol 1,4,5-Trisphosphate)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Caffeine/pharmacology
MH  - Calcium/*metabolism
MH  - Calcium-Transporting ATPases/antagonists & inhibitors
MH  - Cell Membrane/metabolism
MH  - In Vitro Techniques
MH  - Inositol 1,4,5-Trisphosphate/*physiology
MH  - Ion Transport/drug effects
MH  - Lanthanum/physiology
MH  - Mice
MH  - Pancreas/cytology/*metabolism
MH  - Terpenes/*pharmacology
MH  - Thapsigargin
EDAT- 1994/06/01 00:00
MHDA- 1994/06/01 00:01
CRDT- 1994/06/01 00:00
PHST- 1994/06/01 00:00 [pubmed]
PHST- 1994/06/01 00:01 [medline]
PHST- 1994/06/01 00:00 [entrez]
AID - 10.1007/BF00374541 [doi]
PST - ppublish
SO  - Pflugers Arch. 1994 Jun;427(3-4):325-31. doi: 10.1007/BF00374541.