Effect of opioids on acetylcholine release evoked by K+ or glutamic acid from rat neostriatal slices.
Endogenous acetylcholine (ACh) release from rat striatal slices was measured by a chemiluminescent method. Several opiate agents were tested for their ability to modulate ACh release evoked by potassium ions (K+) or glutamic acid (GLU). Morphine, [D-Ala2,Gly(0l)5]-enkephalin (DAGO), [D-Ala2,D-Leu5]-enkephalin (DADLE) and [D-Pen2-D-Pen5]-enkephalin (DPDPE) were found to have an inhibitory effect on K(+)- or GLU-evoked ACh release. This effect was completely blocked by naloxone, but this antagonist by itself had no effect on ACh release. The action of mu-opiate agonists (morphine and DAGO) on ACh release evoked by K+ was sensitive to tetrodotoxin (TTX), but that of delta-opiate agonists (DADLE and DPDPE) was insensitive. The release evoked by GLU was abolished in the presence of TTX. The activation of kappa-opiate receptor by dynorphin-(1-13) had no effect on K(+)- or GLU-evoked ACh release. It is concluded that mu- and delta-opiate agonists, but not kappa, exert an inhibitory control on striatal cholinergic interneurons, but with a different mechanism of action of localization of the receptors. Corticostriatal glutamatergic neurons have an important role in the interaction of the ACh-opioid systems.
Arenas
E
E
Departament de Biologia Cellular i Anatomia Patològica, Facultat de Medicina, Universitat de Barcelona, Spain.
Alberch
J
J
Sanchez Arroyos
R
R
Marsal
J
J
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D013779:Tetrodotoxin / Q000494:pharmacology
D004745:Enkephalins; D005971:Glutamates; D009294:Narcotics; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D009270:Naloxone; D018698:Glutamic Acid; D013779:Tetrodotoxin; D009020:Morphine; D020881:Enkephalin, D-Penicillamine (2,5)-; D000109:Acetylcholine; D011188:Potassium