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

Journal Article · Thu Jun 15 00:00:00 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), Vol. 99:2
• Country of Publication: United States
• Language: English

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ENZYME ACTIVITY
DOPAMINE
SECRETION
MERCURY CHLORIDES
BIOLOGICAL EFFECTS
CELL MEMBRANES
ELECTROPHYSIOLOGY
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OUABAIN
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ACID ANHYDRASES
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AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CHLORIDES
CHLORINE COMPOUNDS
DRUGS
ENZYMES
GLYCOSIDES
HALIDES
HALOGEN COMPOUNDS
HYDROLASES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
MERCURY COMPOUNDS
MERCURY HALIDES
NEUROREGULATORS
ORGANIC COMPOUNDS
PHENOLS
PHOSPHOHYDROLASES
PHYSIOLOGY
POLYPHENOLS
RODENTS
SOMATIC CELLS
STROPHANTHINS
SYMPATHOMIMETICS
VERTEBRATES
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