title: Effects of gabapentin and pregabalin on K+-evoked 3H-GABA and 3H-glutamate release from human neocortical synaptosomes.
abstract: One site of action of the anticonvulsant, analgesic, and anxiolytic drugs gabapentin and pregabalin is the alpha(2)delta-subunit of voltage-sensitive Ca(2+) channels (VSCC). We therefore analyzed the effects of gabapentin and pregabalin on K(+)-evoked release of (3)H-gamma-aminobutyric acid (GABA) and (3)H-glutamate from superfused human neocortical synaptosomes. These neurotransmitters are released by Ca(2+)-dependent exocytosis and by Ca(2+)-independent uptake reversal. When a GABA transport inhibitor was present throughout superfusion to isolate exocytotic conditions, gabapentin and pregabalin (100 microM each) reduced K(+)-evoked (3)H-GABA release by 39% and 47%, respectively. These effects were antagonized by the alpha(2)delta-ligand L: -isoleucine (1 microM) suggesting the alpha(2)delta-subunit of terminal VSCC to mediate the reduction of exocytosis. Both drugs had no effect on exocytotic (3)H-glutamate release and also failed to modulate the release of (3)H-GABA and (3)H-glutamate caused by reversed uptake in the absence of external Ca(2+). Thus, an inhibition of glutamate release by gabapentin and pregabalin as main anticonvulsant principle is not supported by our experiments. An anticonvulsant mode of action of both drugs may be the reduction of a proconvulsant exocytotic GABA release.
authors.affiliation: Section of Clinical Neuropharmacology, Neurozentrum, University of Freiburg, 79106, Freiburg, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Brawek
authors.forename: M
authors.initials: M
authors.lastname: Löffler
authors.forename: A
authors.initials: A
authors.lastname: Weyerbrock
authors.forename: T J
authors.initials: TJ
authors.lastname: Feuerstein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000588:Amines / Q000494:pharmacology*; D000598:Amino Acids, Cyclic / Q000494:pharmacology; D000927:Anticonvulsants / Q000494:pharmacology; D001224:Aspartic Acid / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology*; D005089:Exocytosis / Q000187:drug effects; D005260:Female; D000077206:Gabapentin; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007532:Isoleucine / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D019579:Neocortex / Q000378:metabolism*; D014179:Neurotransmitter Uptake Inhibitors / Q000494:pharmacology; D009557:Nipecotic Acids / Q000494:pharmacology; D010091:Oximes / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D000069583:Pregabalin; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D016559:Tacrolimus / Q000031:analogs & derivatives / Q000494:pharmacology; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology
chemical_list: C112418:32-ascomycinyloxyacetic acid; D000588:Amines; D000598:Amino Acids, Cyclic; D000927:Anticonvulsants; D002121:Calcium Channel Blockers; D003509:Cyclohexanecarboxylic Acids; D014179:Neurotransmitter Uptake Inhibitors; D009557:Nipecotic Acids; D010091:Oximes; C120673:benzyloxyaspartate; D007532:Isoleucine; C078793:NNC 711; C006504:2-aminobicyclo(2,2,1)heptane-2-carboxylic acid; D001224:Aspartic Acid; D018698:Glutamic Acid; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D011188:Potassium; D016559:Tacrolimus