PMID- 7623773
OWN - NLM
STAT- MEDLINE
DCOM- 19950830
LR  - 20131121
IS  - 0026-895X (Print)
IS  - 0026-895X (Linking)
VI  - 48
IP  - 1
DP  - 1995 Jul
TI  - Role of protein kinase C subtypes alpha and delta in the regulation of 
      bradykinin-stimulated phosphoinositide breakdown in astrocytes.
PG  - 39-47
AB  - Cultured astrocytes express bradykinin (BK) receptors coupled to phospholipase C 
      (PLC)-mediated phosphoinositide (PI) hydrolysis. Short term (10- or 90-min) 
      treatment of cells with 1 microM 12-O-tetradecanoylphorbol-13-acetate (TPA) 
      decreased BK-induced PI breakdown, but this inhibitory action was lost after 3-hr 
      TPA treatment. Extended (6- or 24-hr) pretreatment resulted in marked 
      potentiation of the BK response. Western blot analysis using protein kinase C 
      (PKC) isozyme-specific antibodies indicated that astrocytes express PKC-alpha, 
      PKC-delta, and PKC-zeta. With TPA treatment of the cells for various times (10 
      min, 90 min, 3 hr, 6 hr, or 24 hr), translocation of PKC-alpha and PKC-delta from 
      the cytosol to the membrane was seen after 10- or 90-min treatment and 
      restoration to basal levels in the membrane fraction was seen after 3-hr 
      treatment. However, partial or complete down-regulation of PKC-alpha and 
      PKC-delta was seen after 6- or 24-hr treatment, respectively. No translocation or 
      down-regulation of PKC-zeta was seen after either short term or long term TPA 
      treatment. The inactive phorbol ester alpha-TPA had no effect on BK-induced PI 
      hydrolysis or on the translocation or down-regulation of PKC-alpha and PKC-delta. 
      These results suggest that, in unstimulated astrocytes, both PKC-alpha and 
      PKC-delta, but not PKC-zeta, may exert tonic inhibition of BK-mediated PI 
      turnover. After 10- or 90-min TPA treatment, AIF4(-)--but not Ca2+ 
      ionophore-induced PI hydrolysis was inhibited, whereas [3H]BK binding was 
      unaffected, indicating that the site of action of PKC-alpha and PKC-delta in the 
      BK receptor/G protein/PLC pathway is after the receptor and before PLC, i.e., the 
      G protein. After down-regulation of PKC-alpha and -delta, increases in both 
      AIF4(-)-induced inositol phosphate formation and [3H]BK binding contributed to 
      marked potentiation of BK-induced PI responses. Scatchard plot analysis showed an 
      increase in both the maximal number of binding sites and the binding affinity. 
      Both the up-regulation of [3H]BK binding and the subsequent BK-induced PI 
      turnover were blocked by 0.5 microM cycloheximide, a protein synthesis inhibitor. 
      The increase in AIF4(-)-induced PI hydrolysis after 24-hr TPA treatment was also 
      inhibited by cycloheximide, indicating that new synthesis of BK receptors and G 
      proteins was required after down-regulation of PKC-alpha and PKC-delta.(ABSTRACT 
      TRUNCATED AT 400 WORDS)
FAU - Chen, C C
AU  - Chen CC
AD  - Institute of Pharmacology, College of Medicine, National Taiwan University, 
      Taipei.
FAU - Chang, J
AU  - Chang J
FAU - Chen, W C
AU  - Chen WC
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Mol Pharmacol
JT  - Molecular pharmacology
JID - 0035623
RN  - 0 (Isoenzymes)
RN  - 0 (Phosphatidylinositols)
RN  - 10028-17-8 (Tritium)
RN  - EC 2.7.1.- (Prkcd protein, rat)
RN  - EC 2.7.11.13 (Protein Kinase C)
RN  - EC 2.7.11.13 (Protein Kinase C-alpha)
RN  - EC 2.7.11.13 (Protein Kinase C-delta)
RN  - NI40JAQ945 (Tetradecanoylphorbol Acetate)
RN  - S8TIM42R2W (Bradykinin)
SB  - IM
MH  - Animals
MH  - Astrocytes/*drug effects/enzymology/metabolism
MH  - Bradykinin/metabolism/*pharmacology
MH  - Cells, Cultured
MH  - Enzyme Activation
MH  - Hydrolysis
MH  - Immunohistochemistry
MH  - Isoenzymes/*metabolism
MH  - Phosphatidylinositols/*metabolism
MH  - Protein Kinase C/*metabolism
MH  - Protein Kinase C-alpha
MH  - Protein Kinase C-delta
MH  - Radioligand Assay
MH  - Rats
MH  - Rats, Wistar
MH  - Tetradecanoylphorbol Acetate/pharmacology
MH  - Tritium
EDAT- 1995/07/01 00:00
MHDA- 1995/07/01 00:01
CRDT- 1995/07/01 00:00
PHST- 1995/07/01 00:00 [pubmed]
PHST- 1995/07/01 00:01 [medline]
PHST- 1995/07/01 00:00 [entrez]
PST - ppublish
SO  - Mol Pharmacol. 1995 Jul;48(1):39-47.