caa a22 4500 469079134 CHVBK 20180323132944.0 cr unu---uuuuu 170328e19920601xx s 000 0 eng 10.1007/BF00164575 doi (NATIONALLICENCE)springer-10.1007/BF00164575 Opioid receptor-mediated inhibition of 3H-dopamine and 14C-acetylcholine release from rat nucleus accumbens slices [Elektronische Daten] A study on the possible involvement of K+ channels and adenylate cyclase [Menno Heijna, François Hogenboom, Arie Mulder, Anton Schoffelmeer] Summary: The release of 14C-ACh from rat nucleus accumbens slices, induced by 15 mM [K+], was inhibited by the µ- and δ-opioid agonists DAMGO and DPDPE, respectively, whereas only the κ agonist U50,488 reduced the release of 3H-DA. The opioid receptors involved appear to be localized on nerve terminals, since blockade of action potential propagation by 1 μM TTX did not diminish the inhibitory effects of DAMGO, DPDPE or U50,488. Enhancement of the potassium concentration in the superfusion medium to 56 mM with simultaneous reduction of the Ca2+ concentration from 1.2 mM to 0.12 mM induced a release similar to that caused by 15 mM K+ and 1.2 mM Ca+. Under this conditions, the inhibitory effects of both DAMGO and DPDPE on stimulated 14C-ACh release were reduced, whereas the inhibition of evoked 3H-DA release caused by U50,488 was not affected. Activation of µ- as well as δ-opioid receptors by DAMGO and DPDPE, respectively, inhibited forskolin-stimulated adenylate cyclase activity. However, increasing the intracellular cAMP levels with 0.3 mM 8-bromo-CAMP affected neither the depolarization-induced release of 14C-ACh or 3H-DA from accumbens slices nor the inhibitory effects of opioid receptor activation thereon. The results indicate that the mechanism by which functional µ- and δ receptors presynaptically inhibit the depolarization-induced 14C-ACh release from nucleus accumbens slices is likely to involve an increase of potassium channel conductance. In contrast, activation of κ-opioid receptors, which inhibits depolarization-evoked 3H-DA release, apparently does not result in a hyperpolarization of (dopaminergic) nerve terminals. In none of these inhibitory effects presynaptic adenylate cyclase appears to be involved. Springer-Verlag, 1992 Opioid receptor types nationallicence Dopamine release nationallicence Acetylcholine release nationallicence Potassium channels nationallicence Adenylate cyclase nationallicence Heijna Menno Department of Pharmacology, Free University, Medical Faculty, Van den Boechorststraat 7, NL-1081, BT Amsterdam, The Netherlands aut Hogenboom François Department of Pharmacology, Free University, Medical Faculty, Van den Boechorststraat 7, NL-1081, BT Amsterdam, The Netherlands aut Mulder Arie Department of Pharmacology, Free University, Medical Faculty, Van den Boechorststraat 7, NL-1081, BT Amsterdam, The Netherlands aut Schoffelmeer Anton Department of Pharmacology, Free University, Medical Faculty, Van den Boechorststraat 7, NL-1081, BT Amsterdam, The Netherlands aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/6(1992-06-01), 627-632 0028-1298 345:6<627 1992 345 210 https://doi.org/10.1007/BF00164575 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00164575 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Heijna Menno Department of Pharmacology, Free University, Medical Faculty, Van den Boechorststraat 7, NL-1081, BT Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Hogenboom François Department of Pharmacology, Free University, Medical Faculty, Van den Boechorststraat 7, NL-1081, BT Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Mulder Arie Department of Pharmacology, Free University, Medical Faculty, Van den Boechorststraat 7, NL-1081, BT Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Schoffelmeer Anton Department of Pharmacology, Free University, Medical Faculty, Van den Boechorststraat 7, NL-1081, BT Amsterdam, The Netherlands aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/6(1992-06-01), 627-632 0028-1298 345:6<627 1992 345 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer