Involvement of intracellular Ca2+ elevation but not cyclic AMP in PACAP-induced p38 MAP kinase activation in PC12 cells

Regul Pept. 2002 Nov 15;109(1-3):149-53. doi: 10.1016/s0167-0115(02)00198-2.


We have recently shown that in PC12 cells, pituitary adenylate cyclase-activating polypeptide (PACAP) and NGF synergistically stimulate PACAP mRNA expression primarily via a mechanism involving a p38 mitogen-activated protein kinase (MAPK)-dependent pathway. Here we have analyzed p38 MAPK activation by PACAP and the mechanism underlying this action of PACAP in PC12 cells. PACAP increased phosphorylation of p38 MAPK with a bell-shaped dose-response relationship and a maximal effect was obtained at 10(-8) M. PACAP (10(-8) M)-induced p38 MAPK phosphorylation was already evident at 2.5 min, maximal at 5 min, and rapidly declined thereafter. PACAP-induced p38 MAPK phosphorylation was potently inhibited by depletion of Ca(2+) stores with thapsigargin and partially inhibited by the phospholipase C inhibitor U-73122, L-type voltage-dependent calcium channel inhibitors nifedipine and nimodipine, and the Ca(2+) chelator EGTA, whereas the protein kinase C inhibitor calphostin C, the protein kinase A inhibitor H-89, the cAMP antagonist Rp-cAMP, and the nonselective cation channel blocker SKF96365 had no effect. These results indicate that PACAP activates p38 MAPK in PC12 cells through activation of a phospholipase C, mobilization of intracellular Ca(2+) stores, and Ca(2+) influx through voltage-dependent Ca(2+) channels, but not cyclic AMP-dependent mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology
  • Cyclic AMP / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Enzyme Activation / drug effects
  • Intracellular Fluid / drug effects*
  • Intracellular Fluid / metabolism*
  • Mitogen-Activated Protein Kinases / metabolism*
  • Naphthalenes / pharmacology
  • Neuropeptides / pharmacology*
  • PC12 Cells
  • Phosphorylation / drug effects
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • Rats
  • Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
  • Receptors, Pituitary Hormone / metabolism
  • Signal Transduction / drug effects*
  • Tumor Cells, Cultured
  • Type C Phospholipases / metabolism
  • p38 Mitogen-Activated Protein Kinases


  • Adcyap1 protein, rat
  • Calcium Channel Blockers
  • Naphthalenes
  • Neuropeptides
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
  • Receptors, Pituitary Hormone
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • Type C Phospholipases
  • calphostin C
  • Calcium