title: Role of D2 dopamine receptors of the ventral pallidum in inhibitory avoidance learning.
abstract: In our present experiments, the role of D2 dopamine (DA) receptors of the ventral pallidum (VP) was investigated in one trial step-through inhibitory avoidance paradigm. Animals were shocked 3 times in the conditioning trial, with 0.5mA current for 1s. Subsequently bilateral microinjection of the D2 DA receptor agonist quinpirole was administered into the VP in three doses (0.1μg, 1.0μg or 5.0μg in 0.4μl saline). We also applied the D2 DA receptor antagonist sulpiride (0.4μg in 0.4μl saline) alone or 15min prior to the agonist treatment to elucidate whether the agonist effect was specific for the D2 DA receptors. Control animals received saline. In a supplementary experiment, it was also investigated whether application of the same conditioning method leads to the formation of short-term memory in the experimental animals. In the experiment with the D2 DA receptor agonist, only the 0.1μg quinpirole increased significantly the step-through latency during the test trials: retention was significant compared to the controls even 2 weeks after conditioning. The D2 DA receptor antagonist sulpiride pretreatment proved that the effect was due to the agonist induced activation of the D2 DA receptors of the VP. The supplementary experiment demonstrated that short-term memory is formed after conditioning in the experimental animals, supporting that the agonist enhanced memory consolidation in the first two experiments. Our results show that the activation of the D2 DA receptors in the VP facilitates memory consolidation as well as memory-retention in inhibitory avoidance paradigm.
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary; Molecular Neuroendocrinology and Neurophysiology Research Group, Pécs University, Szentágothai Research Center, Pécs, Hungary. Electronic address: laszlo.lenard@aok.pte.hu.
authors.forename: László
authors.initials: L
authors.lastname: Lénárd
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Ollmann
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: Kristóf
authors.initials: K
authors.lastname: László
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: Anita
authors.initials: A
authors.lastname: Kovács
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: Rita
authors.initials: R
authors.lastname: Gálosi
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: Veronika
authors.initials: V
authors.lastname: Kállai
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: Tóth
authors.initials: T
authors.lastname: Attila
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: Erika
authors.initials: E
authors.lastname: Kertes
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: Olga
authors.initials: O
authors.lastname: Zagoracz
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary; Molecular Neuroendocrinology and Neurophysiology Research Group, Pécs University, Szentágothai Research Center, Pécs, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Karádi
authors.affiliation: Institute of Physiology, Pécs University, Medical School, Pécs, Hungary.
authors.forename: László
authors.initials: L
authors.lastname: Péczely
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D066187:Basal Forebrain / Q000187:drug effects / Q000378:metabolism*; D002408:Catheters, Indwelling; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004597:Electroshock; D007266:Inhibition, Psychological; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects / Q000502:physiology; D008845:Microinjections; D011581:Psychological Tests; D019257:Quinpirole / Q000494:pharmacology; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000378:metabolism*; D013469:Sulpiride / Q000494:pharmacology
chemical_list: C000607792:DRD2 protein, rat; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D017448:Receptors, Dopamine D2; D019257:Quinpirole; D013469:Sulpiride
keywords: D2 dopamine receptors; Inhibitory avoidance learning; Memory consolidation; Quinpirole; Sulpiride; Ventral pallidum