Effect of evodiamine on catecholamine secretion from bovine adrenal medulla

The effect of evodiamine on catecholamine secretion from bovine adrenal medulla was investigated. Evodiamine, a bioactive component isolated from dry unripened fruit of Evodia rutaecarpa Bentham, was found to stimulate the secretion of catecholamine from perfused bovine adrenal medulla at a concentration of 10 μM and its effect persisted for at least 30 min. This stimulatory effect of evodiamine was abolished by omission of Ca2+ from the perfusion fluid. Evodiamine (0.1-10 μM) markedly enhanced the secretion of catecholamine from the adrenal medulla induced by acetylcholine (100 μM) or high K+(56 mM). The secretion of catecholamine was promptly enhanced by acetylcholine or high K+, but returned to the control level on treatment for 20 min. However, when evodiamine was added to the perfusion fluid after acetylcholine or high K+ stimulation for 10 min, the secretion of catecholamine again increased greatly. These results indicate that evodiamine not only stimulated the secretion of catecholamine from bovine adrenal medulla but also reversed insensitivity of these cells to acetylcholine or high K+ stimulation

Chronic coadministration of carbamazepine together with imipramine produces antidepressant-like effects in an ACTH-induced animal model of treatment–resistant depression: Involvement of 5-HT 2A receptors?

The use of carbamazepine has been reported to be an effective treatment for severe depression. We have already shown that the antidepressant-like effects of tricyclic antidepressants in the rat forced swim test (FST) are blocked by chronic treatment with adrenocorticotropic hormone (ACTH). In the present study, we examined the effect of the chronic administration of carbamazepine on the FST and the wet-dog shakes induced by (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aiminopropane (DOI), a 5-HT2A receptor agonist, in ACTH-treated rats. Chronic administration of carbamazepine did not affect the duration of immobility in saline-treated and ACTH-treated rats. The reduction of immobility, induced by chronic administration of imipramine, was blocked by treatment with ACTH. When carbamazepine was administered concurrently with imipramine, we observed a significant decrease in immobility in rats treated with ACTH. Chronic ACTH treatment increased the number of the wet-dog shakes induced by DOI. This effect of ACTH was significantly increased by the coadministration of carbamazepine and imipramine. These results suggest that the use of carbamazepine together with tricyclic antidepressants had the effect of reducing immobility time in the FST in a tricyclic antidepressant-treatment-resistant depressive model induced by chronic ACTH treatment. </p

Efficient overall water splitting in acid with anisotropic metal nanosheets

超高効率な水の電気分解を実現するナノシート状合金触媒を開発 --再生可能エネルギーによる水素社会実現へ大きく貢献--. 京都大学プレスリリース. 2021-02-17.Water is the only available fossil-free source of hydrogen. Splitting water electrochemically is among the most used techniques, however, it accounts for only 4% of global hydrogen production. One of the reasons is the high cost and low performance of catalysts promoting the oxygen evolution reaction (OER). Here, we report a highly efficient catalyst in acid, that is, solid-solution Ru‒Ir nanosized-coral (RuIr-NC) consisting of 3 nm-thick sheets with only 6 at.% Ir. Among OER catalysts, RuIr-NC shows the highest intrinsic activity and stability. A home-made overall water splitting cell using RuIr-NC as both electrodes can reach 10 mA cm−2geo at 1.485 V for 120 h without noticeable degradation, which outperforms known cells. Operando spectroscopy and atomic-resolution electron microscopy indicate that the high-performance results from the ability of the preferentially exposed {0001} facets to resist the formation of dissolvable metal oxides and to transform ephemeral Ru into a long-lived catalyst

Effect of GBR12909 on affective behavior: Distinguishing motivational behavior from antidepressant-like and addiction-like behavior using the runway model of intracranial self-stimulation

Rationale: 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