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

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 proteinmore » that is not G/sub i/ is involved in receptor-mediated stimulation of InsP formation in 1321N1 human astrocytoma cells.« less
Authors:
;
Publication Date:
OSTI Identifier:
6846349
Report Number(s):
CONF-8604222-
Journal ID: CODEN: FEPRA; TRN: 87-008623
Resource Type:
Journal Article
Resource Relation:
Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States); Journal Volume: 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
Research Org:
Univ. of North Carolina School of Medicine, Chapel Hill
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; HORMONES; BIOCHEMICAL REACTION KINETICS; PHOSPHORIC ACID ESTERS; BIOSYNTHESIS; TUMOR CELLS; BIOCHEMISTRY; CELL MEMBRANES; INOSITOL; MAN; NUCLEOTIDES; TOXINS; TRACER TECHNIQUES; ANIMAL CELLS; ANIMALS; ANTIGENS; CARBOHYDRATES; CELL CONSTITUENTS; CHEMISTRY; ESTERS; INOSITOLS; ISOTOPE APPLICATIONS; KINETICS; MAMMALS; MATERIALS; MEMBRANES; MONOSACCHARIDES; ORGANIC COMPOUNDS; ORGANIC PHOSPHORUS COMPOUNDS; PRIMATES; REACTION KINETICS; SACCHARIDES; SYNTHESIS; TOXIC MATERIALS; VERTEBRATES 550201* -- Biochemistry-- Tracer Techniques; 550901 -- Pathology-- Tracer Techniques