Effects of mercuric chloride on (/sup 3/H)dopamine release from rat brain striatal synaptosomes

Journal Article · Thu Jun 15 04:00:00 EDT 1989 · Toxicol. Appl. Pharmacol.; (United States)

DOI:https://doi.org/10.1016/0041-008X(89)90009-4· OSTI ID:5764209

Hare, M F; Minnema, D J; Cooper, G P; Michaelson, I A

Electrophysiological studies employing amphibian neuromuscular preparations have shown that mercuric chloride (HgCl2) in vitro increases both spontaneous and evoked neurotransmitter release. The present study examines the effect of HgCl2 on the release of (/sup 3/H)dopamine from synaptosomes prepared from mammalian brain tissue. Mercuric chloride (3-10 microM) produces a concentration-dependent increase in spontaneous (/sup 3/H)dopamine release from ''purified'' rat striatal synaptosomes, in both the presence and absence of extra-synaptosomal calcium. The effects of HgCl2 on transmitter release from amphibian neuromuscular junction preparations resemble those produced by the Na+, K+-ATPase inhibitor ouabain. Experiments were performed to determine whether the HgCl2 effects on mammalian synaptosomal dopamine release are a consequence of Na+, K+-ATPase inhibition. Na+, K+-ATPase activity in lysed synaptosomal membranes is inhibited by HgCl2 (IC50 = 160 nM). However, mercuric chloride in the presence of 1 mM ouabain still increased (3H)dopamine release. The specific inhibitor of Na+-dependent, high-affinity dopamine transport, RMI81,182 inhibited ouabain-induced (3H)dopamine release whereas it had no effect on HgCl2-induced (/sup 3/H)dopamine release. These data suggest that augmentation of spontaneous (/sup 3/H)dopamine release by HgCl2 probably is not mediated by an inhibition of Na+, K+-ATPase and HgCl2 does not act directly on the dopamine transporter.

• Research Organization: Univ. of Cincinnati College of Medicine, OH (USA)
• OSTI ID: 5764209
• Journal Information: Toxicol. Appl. Pharmacol.; (United States), Journal Name: Toxicol. Appl. Pharmacol.; (United States) Vol. 99:2; ISSN TXAPA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID ANHYDRASES
AMINES
ANIMAL CELLS
ANIMALS
AROMATICS
ATP-ASE
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL EFFECTS
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CELL MEMBRANES
CHLORIDES
CHLORINE COMPOUNDS
DOPAMINE
DRUGS
ELECTROPHYSIOLOGY
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
GLYCOSIDES
HALIDES
HALOGEN COMPOUNDS
HYDROLASES
HYDROXY COMPOUNDS
IN VITRO
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE TRANSPORT
MEMBRANES
MERCURY CHLORIDES
MERCURY COMPOUNDS
MERCURY HALIDES
NERVE CELLS
NEUROREGULATORS
ORGANIC COMPOUNDS
OUABAIN
PHENOLS
PHOSPHOHYDROLASES
PHYSIOLOGY
POLYPHENOLS
RATS
RODENTS
SECRETION
SOMATIC CELLS
STROPHANTHINS
SYMPATHOMIMETICS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES