Amitriptyline inhibits striatal efflux of neurotransmitters via blockade of voltage-dependent Na+ channels.
Amitriptyline, a tricyclic antidepressant, almost completely inhibited veratridine- or scorpion toxin-evoked efflux of endogenous dopamine (DA) and gamma-aminobutyric acid (GABA) from rat striatal slices without any effects of 30 mM K+ or 4-aminopyridine on basal and evoked efflux. The effects of amitriptyline on glutamate efflux were comparable to those on DA or GABA efflux. These effects of amitriptyline can be well explained by its blockade of voltage-dependent Na+ channels and may be independent of other activities of this drug such as re-uptake inhibition of monoamines and blockade of K+ channels.
Department of Psychopharmacology, Tokyo Institute of Psychiatry, Japan.
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Ishii
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Sumi
D000639:Amitriptyline / Q000494:pharmacology*; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005971:Glutamates; D015222:Sodium Channels; D000639:Amitriptyline; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D004298:Dopamine