Tetrodotoxin-insensitive Na+ channel activator palytoxin inhibits tyrosine uptake into cultured bovine adrenal chromaffin cells

Journal Article · Mon Jul 01 00:00:00 EDT 1991 · Molecular Pharmacology; (United States)

OSTI ID:5463882

Morita, K; Teraoka, K; Azuma, M; Oka, M; Hamano, S ^[1]

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1. Department of Pharmacology, Tokushima University School of Medicine (Japan)

The effects of the tetrodotoxin-insensitive Na+ channel activator palytoxin on both the secretion of endogenous catecholamines and the formation of 14C-catecholamines from (14C)tyrosine were examined using cultured bovine adrenal chromaffin cells. Palytoxin was shown to cause the stimulation of catecholamine secretion in a concentration-dependent manner. However, this toxin caused the reduction rather than the stimulation of 14C-catecholamine formation at the same concentrations. Palytoxin failed to cause any alteration in the activity of tyrosine hydroxylase prepared from bovine adrenal medulla. Furthermore, the uptake of (14C)tyrosine into the cells was shown to be inhibited by this toxin under the conditions in which the suppression of 14C-catecholamine formation was observed, and this inhibitory action on tyrosine uptake was closely correlated with that on catecholamine formation. The inhibitory action of palytoxin on tyrosine uptake into the cells was observed to be noncompetitive, and this effect was not altered by the removal of Na+ from the incubation mixture. These results suggest that palytoxin may be able to inhibit the uptake of (14C)tyrosine into the cells, resulting in the suppression of 14C-catecholamine formation, probably through its direct action on the plasma membranes of bovine adrenal chromaffin cells.

• OSTI ID: 5463882
• Journal Information: Molecular Pharmacology; (United States), Vol. 40:1; ISSN 0026-895X
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CATECHOLAMINES
BIOSYNTHESIS
TOXINS
BIOCHEMICAL REACTION KINETICS
TYROSINE
UPTAKE
ADRENAL GLANDS
ANIMAL CELLS
CARBON 14 COMPOUNDS
CATTLE
CELL CULTURES
DOSE-RESPONSE RELATIONSHIPS
INHIBITION
PHARMACOLOGY
SODIUM COMPOUNDS
TRACER TECHNIQUES
ALKALI METAL COMPOUNDS
AMINES
AMINO ACIDS
ANIMALS
ANTIGENS
AROMATICS
BODY
CARBON COMPOUNDS
CARBOXYLIC ACIDS
DOMESTIC ANIMALS
ENDOCRINE GLANDS
GLANDS
HYDROXY ACIDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MATERIALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PHENOLS
POLYPHENOLS
REACTION KINETICS
RUMINANTS
SYNTHESIS
TOXIC MATERIALS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques