Differential regulation by N-methyl-D-aspartate and non-N-methyl-D-aspartate receptors of acetylcholine release from the rat striatum in vivo.
The modulation of striatal cholinergic neurons by glutamatergic inputs was studied by monitoring the output of acetylcholine collected via a transversal microdialysis probe implanted into the striatum of freely moving rats. A transversal microdialysis membrane was inserted in the striatum and acetylcholine or GABA levels in the dialysate were measured. Acetylcholine levels in the dialysate were quantified by a high-performance liquid chromatography method with an electrochemical detector, while GABA levels were measured by a high-performance liquid chromatography method with a fluorescence detector. The dialysis membrane was perfused with Ringer solution containing 7 microM physostigmine sulphate and drugs, dissolved in the perfusion solution, were administered locally via the dialysis membrane. Local administration of the N-methyl-D-aspartate antagonist 3-[(RS)-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid (25-100 microM) brought about a decrease in striatal acetylcholine output which was dose-dependent, reversible and partially antagonized by 100 microM N-methyl-D-aspartate. On the other hand, local administration of the non-N-methyl-D-aspartate antagonist 2,3-dihydroxy-6-nitro-7-sulfamoil-benzo(F)quinoxaline was followed by an increase in acetylcholine output which reached a maximum of about +55% at 12.8 microM 2,3-dihydroxy-6-nitro-7-sulfamoil-benzo(F)quinoxaline and was readily reversed when the drug was withdrawn from the perfusion solution. Local administration of the non-N-methyl-D-aspartate receptor agonist (S)-alfa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (50 and 200 microM) decreased acetylcholine output and this effect was reversed by simultaneous perfusion with the GABA antagonist bicuculline (50 microM).(ABSTRACT TRUNCATED AT 250 WORDS)
Giovannini
M G
MG
Department of Preclinical and Clinical Pharmacology, University of Florence, Italy.
Camilli
F
F
Mundula
A
A
Bianchi
L
L
Colivicchi
M A
MA
Pepeu
G
G
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D008297:Male; D017551:Microdialysis; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors; D017470:Receptors, Glutamate / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D010879:Piperazines; D011810:Quinoxalines; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D005680:gamma-Aminobutyric Acid; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; C050592:3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid; D000109:Acetylcholine