GABAA and GABAB antagonists prevent the opioid inhibition of endogenous acetylcholine release evoked by glutamate from rat neostriatal slices.
We have examined the role of the GABAergic system in the opioid inhibition of endogenous acetylcholine (ACh) release from rat neostriatal slices by blocking either gamma-aminobutyric acid-A (GABAA) or GABAB receptors. GABAergic antagonists (bicuculline or phaclofen) completely blocked mu- (morphine or DAGO) and delta-opioid (DPDPE) inhibition of glutamate-evoked endogenous ACh release in a concentration-dependent manner. However, GABA antagonists were ineffective in blocking the opioid inhibition of potassium-evoked endogenous ACh release. These findings point to the important role of the GABAergic system in the regulation of mu- and delta-opioid inhibition of cholinergic neurons stimulated by glutamate.
Arenas
E
E
Departament de Biologia Cellular i Anatomia Patològica, Facultat de Medicina, Universitat de Barcelona, Spain.
Marsal
J
J
Alberch
J
J
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001418:Baclofen / Q000031:analogs & derivatives* / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000494:pharmacology; D018756:GABA Antagonists; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D066298:In Vitro Techniques; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D004745:Enkephalins; D018756:GABA Antagonists; D005971:Glutamates; D009294:Narcotics; D011963:Receptors, GABA-A; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; C052329:phaclofen; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D009020:Morphine; D020881:Enkephalin, D-Penicillamine (2,5)-; D001418:Baclofen; D000109:Acetylcholine; D001640:Bicuculline