Isosteric replacement of the phenolic hydroxyl group in potent vanilloid receptor (VR1) agonists with the alkylsulfonamido group provides a series of compounds which are effective antagonists to the action of the capsaicin on rat VR1 heterologously expressed in Chinese hamster ovary (CHO) cells. In particular, compound 61, N-[2-(3,4-dimethylbenzyl)-3-pivaloyloxypropyl]-N'-[3-fluoro-4-(methylsulfonylamino)benzyl]thiourea was a full antagonist against capsaicin, displayed a K(i) value of 7.8 nM (compared to 520 nM for capsazepine and 4 nM for 5-iodoRTX), and showed excellent analgesic activity in mice. Structure-activity analysis of the influence of modifications in the A- and C-regions of 4-methylsulfonamide ligands on VR1 agonism/antagonism indicated that 3-fluoro substitution in the A-region and a 4-tert-butylbenzyl moiety in the C-region favored antagonism, whereas a 3-methoxy group in the A-region and 3-acyloxy-2-benzylpropyl moieties in the C-region favored agonism.

Genes are attractive candidates as therapeutic agents, and the development of safe and effective gene carriers is essential for the success of human gene therapy. To develop a gene delivery vector that shows low cytotoxicity and high efficiency, we synthesized poly-L-lysine-g-pluronic by conjugating poly-L-lysine (PLL) to pluronic, which is partially functionalized with para-nitrophenyl carbonate groups, and evaluated for its efficiency as a possible nonviral gene carrier candidate. Structural analysis of synthesized polymer was performed by using 1H-NMR. Gel retardation assay, zeta potential and size measurement confirmed that the new gene carrier made a compact complex with plasmid DNA. pCMV-beta-gal was used as a reporter gene, and the in vitro transfection efficiency was measured in HeLa cells by using the o-nitrophenyl-beta-D-galactopyranoside assay. The highest transfection efficiency among those tested was achieved at the 1:1 weight ratio of polymer:DNA, and a 3-fold increase in transfection efficiency was achieved by treatment of a lysosomotropic agent, chloroquine. Compared with unmodified PLL, PLL-g-pluronic showed about 2-fold increase in transfection efficiency with similar cytotoxicity specifically at the 1:1 weight ratio of polymer:DNA.

We previously reported that p-synephrine has antidepressant-like activity in the murine models of forced swimming and tail suspension. In the present study, we characterized antidepressant-like effects of p-synephrine stereoisomers in both in vivo and in vitro systems. In the tail suspension test, S-(+)-p-synephrine (3 mg/kg, p.o.) reduced the duration of immobility, while R-(-)-p-synephrine (0.3-3 mg/kg, p.o.) had no effect. S-(+)-p-synephrine (0.3, 1 and 3 mg/kg, p.o.) and R-(-)-p-synephrine (1 mg/ kg and 3 mg/kg, p.o.) significantly reversed the reserpine (2.5 mg/kg, i.p.)-induced hypothermia. S-(+)-p-synephrine was more effective than R-(-)-p-synephrine in inhibition of both [3H]noradrenaline uptake in rat cerebral cortical slices (maximal inhibition 85.7 +/- 7.8% vs. 59.8 +/- 4.3%; EC50 5.8 +/- 0.7 microM vs. 13.5 +/- 1.2 microM) and [3H]nisoxetine binding (Ki 4.5 +/- 0.5 microM vs. 8.2 +/- 0.7 microM). In contrast, R-(-)-p-synephrine was more effective than S-(+)-p-synephrine in stimulation of [3H]noradrenaline release from rat cerebral cortical slices (maximal stimulation 23.9 +/- 1.8% vs. 20.1 +/- 1.7%; EC50 8.2 +/- 0.6 microM vs. EC50 12.3 +/- 0.9 microM). The stimulatory effect of R-(-)-p-synephrine on [3H]noradrenaline release was inhibited by nisoxetine (100 nM), but tetrodotoxin (1 microM) and elimination of extracellular calcium had no effect. It is suggested that S-(+)-p-synephrine has more effective antidepressant-like activity than R-(-)-p-synephrine.

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