In this study we report that substance P stimulated [H-3]glycogen brea
kdown and elevation of intracellular Ca2+ concentration in the human a
strocytoma cell line UC-11MG. Both effects were dose dependent, and co
mpletely blocked by CP-96,345 suggesting the involvement of an NK1 rec
eptor. Our previous studies indicated that norepinephrine and histamin
e stimulate glycogenolysis via cAMP and Ca2+ respectively. Combined st
imulation with substance P and norepinephrine or histamine resulted in
additive effects suggesting that there is no interaction between thes
e neurotransmitters in regulating glycogenolysis in these cells. These
results confirm that UC-11MG cells are a useful model system to inves
tigate the functional role of neurotransmitter receptors in astroglial
cells.