Guanine nucleotide-dependent, pertussis toxin-insensitive, stimulation of inositol phosphate formation by carbachol in a membrane preparation from astrocytoma cells

Journal Article · Tue Mar 04 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

DOI:https://doi.org/10.1042/bj2390141· OSTI ID:6846349

Hepler, J R; Harden, T K

Formation of the inositol phosphates (InsP), InsP/sub 3/, InsP/sub 2/, and InsP/sub 1/ was increased in a concentration dependent manner (K/sub 0.5/ approx. 5 ..mu..M) by GTP..sigma..S in washed membranes prepared from /sup 3/H-inositol-prelabelled 1321N1 human astrocytoma cells. Both GTP..gamma..S and GppNHp stimulated InsP formation by 2-3 fold over control; GTP and GDP were much less efficacious and GMP had no effect. Although the muscarinic cholinergic receptor agonist carbachol had no effect in the absence of guanine nucleotide, in the presence of 10 ..mu..M GTP..gamma..S, carbachol stimulated (K/sub 0.5/ approx. 10 ..mu.. M) the formation of InsP above the level achieved with GTP..gamma..S alone. The effect of carbachol was completely blocked by atropine. The order of potency for a series of nucleotides for stimulation of InsP formation in the presence of 500 ..mu..M carbachol was GTP..gamma..S > GppNHp > GTP = GDP. Pertussis toxin, at concentrations that fully ADP-ribosylate and functionally inactivate G/sub i/, had no effect on InsP formation in the presence of GTP..gamma..S or GTP..gamma..S plus carbachol. Histamine and bradykinin also stimulated InsP formation in the presence of GTP..gamma..S in washed membranes from 1321N1 cells. These data are consistent with the idea that a guanine nucleotide regulatory protein that is not G/sub i/ is involved in receptor-mediated stimulation of InsP formation in 1321N1 human astrocytoma cells.

• Research Organization: Univ. of North Carolina School of Medicine, Chapel Hill
• OSTI ID: 6846349
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
ANTIGENS
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BIOSYNTHESIS
CARBOHYDRATES
CELL CONSTITUENTS
CELL MEMBRANES
CHEMISTRY
ESTERS
HORMONES
INOSITOL
INOSITOLS
ISOTOPE APPLICATIONS
KINETICS
MAMMALS
MAN
MATERIALS
MEMBRANES
MONOSACCHARIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHORIC ACID ESTERS
PRIMATES
REACTION KINETICS
SACCHARIDES
SYNTHESIS
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES
TUMOR CELLS
VERTEBRATES