Okayama University Medical SchoolActa Medica Okayama0386-300X6852014Characteristics of the Runway Model of Intracranial Self-stimulation Behavior and Comparison with Other Motivated Behaviors255262ENSatoruEsumiYoichiKawasakiYutakaGomitaYoshihisaKitamuraToshiakiSendoReview10.18926/AMO/52893Motivation incorporates several psychological aspects that produce reward-related and learning behaviors. Although reward-related behavior is reported to be mediated by the dopaminergic reward pathway, the involvement of dopaminergic systems in motivated behavior has not been fully clarified. Several experimental methodologies for motivational behavior have been reported, but pharmacological characteristics seem to vary among these methodologies. In this review, we attempt to summarize three main concepts:(1) the relationship of dopamine neuron physiology with motivated behavior, (2) the pharmacological characteristics of the runway intracranial self-stimulation model, and (3) the behavioral distinction of disparate motivated behaviors.No potential conflict of interest relevant to this article was reported.Acta Medica Okayama0918-615835102012Quantitation and Human Monocyte Cytotoxicity of the Polymerization Agent 1-Hydroxycyclohexyl Phenyl Ketone (Irgacure 184) from Three Brands of Aqueous Injection Solution18211825ENKazuhikoYamajiYoichiKawasakiKeiYoshitomeHisashiMatsunagaToshiakiSendoIn this study, levels of the photoinitiator 1-hydroxycyclohexyl phenyl ketone (1-HCHPK) in aqueous injection solutions were analyzed by GC-MS. In our previous studies, photoinitiators such as 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MTMP) were detected in intravenous (i.v.) injection bag solution, and they were found to be cytotoxic to human monocytes. Therefore, we hypothesized that 1-HCHPK might display similarly cytotoxicity. The purpose of this study was to quantitate the amount of contaminants from plastic containers such as those used for peripheral parenteral nutrition and to determine the cytotoxicity of such extracts on human monocytes. The sample extraction procedure for GC-MS analysis involved a liquid-phase extraction. The solvent was evaporated under a stream of nitrogen at 50 degrees C to yield a residue, which was dissolved in n-hexane and injected into a GC-MS. Normal human peripheral blood mononuclear cells (PBMC), isolated from the buffy coat by centrifugation, were suspended in RPMI 1640 medium supplemented with 10% (v/v) heat-inactivated fetal calf serum. In the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay, cells (1x10(4)) were treated with 1-HCHPK for 24h or 48h at 37 degrees C. From the GC-MS analysis, 6.13-8.32 mu g/mL of 1-HCHPK was found in 20 mL vials of water for injection solution. In the MTT assay, 1-HCHPK decreased cell viability for both the 24h and 48h incubation periods. In conclusion, our findings suggest that 1-HCHPK could promote adverse events in patients. Future studies will clarify the possible health risks of photoinitiator accumulation in human cells.No potential conflict of interest relevant to this article was reported.岡山医学会Acta Medica Okayama0030-155812532013薬物相互作用 (28―過活動膀胱治療薬の薬物相互作用）259262ENYusukeHarutaYoichiKawasakiYoshihisaKitamuraToshiakiSendoNo potential conflict of interest relevant to this article was reported.岡山医学会Acta Medica Okayama0030-155812532013GBR12909の情動行動への影響：脳内自己刺激行動の Runway法を用いた動機付け行動と，抗うつ様行動および依存様行動の区別205209ENSatoruEsumiHidenoriSagaraAkihikoNakamotoYoichiKawasakiYutakaGomitaToshiakiSendoNo potential conflict of interest relevant to this article was reported.Acta Medica Okayama0166-43282432013Effect of GBR12909 on affective behavior: Distinguishing motivational behavior from antidepressant-like and addiction-like behavior using the runway model of intracranial self-stimulation313321ENSatoruEsumiHidenoriSagaraAkihikoNakamotoYoichiKawasakiYutakaGomitaToshiakiSendoRationale: It was recently demonstrated that the priming stimulation effect (PSE) in the runway model of intracranial self-stimulation (ICSS) can be used as a model system to study the motivational effects of drugs. However, the characteristics of this navel experimental model have not been fully clarified.
Objective: To elucidate the involvement of dopamine uptake inhibition in motivated behavior and the difference in experimental characteristics between closely related experimental models, we investigated the effects of the dopamine uptake inhibitor GBR12909 in the runway ICSS model, in the forced swimming test (FST), and on conditioned place preference (CPP). In addition, the role of dopamine receptor signaling in the runway model was evaluated using dopamine receptor agonists and antagonists.
Results: GBR12909 dose-dependently increased running speed on the runway and decreased immobility time in the FST without affecting the time spent in the drug-associated compartment in CPP tests. The effect of GBR12909 in the runway model was inhibited by pre-treatment with the dopamine receptor antagonists haloperidol and raclopride. The dopamine receptor agonists SKF38393 and quinpirole dose-dependently decreased running speed.
Conclusions: These results demonstrate that GBR12909 displays motivation-enhancing and antidepressant-like effects without place conditioning effects. In addition, the mechanisms of PSE enhancement in the runway ICSS model are different from those underlying closely associated experimental models and are mediated by increases in dopamine signaling.No potential conflict of interest relevant to this article was reported.