• Biomedical Science Letters
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• v.23 no.1
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• pp.17-24
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• 2017

Estrogens are effective neuroprotectants in vivo and in vitro. To obtain a better insight into the molecular mechanisms of action of neuroprotection by $17{\beta}-estradiol$ (E2), we examined the differential effects of E2 on the fluidity of synaptosomal plasma membrane vesicles (SPMV) isolated from rat cerebral cortex. Intramolecular excimerization of 1,3-di(1-pyrenyl)-propane (Py-3-Py) was used to investigate the effects of E2 on the bulk and annular lateral diffusion of the SPMV. In addition, we examined the effects of E2 on the rotational diffusion of individual leaflet of SPMV exploiting selective quenching of outer monolayer 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence by trinitrophenyl groups. The $F{\ddot{o}}rster$ distance $R_0$ value for the tryptophan-Py-3-Py donor-acceptor pair was $26.9{\AA}$. E2 increased the lateral mobility of both bulk and annular lipids in SPMV in a dose-dependent manner, but a larger effect on bulk lipids was observed. Although E2 decreased the anisotropy of DPH in SPMV, E2 had a greater fluidizing effect on the outer leaflet compared to the inner leaflet. These results suggest that E2 selectively fluidizes the more fluid regions within SPMV. It is highly probable that E2 mostly fluidizes the bulk lipids, away from either annular lipids or lipid rafts, in the outer leaflet of SPMV. This selective fluidization may be one of the nongenomic mechanisms of neuroprotection by E2.

• Archives of Pharmacal Research
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• v.15 no.2
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• pp.152-161
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• 1992

Selective quenching of 1, 6-diphenyl-1, 3, 5-hexatriene (DPH) by trinitrophenyl groups was utilized to examine the transbilayer fluidity asymmetry of model membranes of phospholipids (SPMVPL) extracted from synaptosomal plasma membrane vesicles (SPMV). The polarization (P), anisotropy (r), limiting anisotropy $(r_\infty$), and order parameter (S) of DPH in the inner monolayer were 0.019, 0.014, 0.018, and 0.047, respectively, greater than calculated for the outer monolayer of SPMVPL. Selective quenching of DPH by trinitrophenyl groups was also utilized to examine the effects of n-alkanols on the individual monolayer structure of SPMVPL. n-Alkanols fluidized the hydrocarbon region of bulk SPMVPL and the potencies of n-alkanols up to 1-nonanon increased with carbon chain length. It appears that the potencies in bilayer fluidization increase by 1 order of magnitude as the carbon chain length increases by two carbon atoms. The cut-off phenomenon was reached at 1-decanol, where further increase in hydrocarbon length resulted in a decrease in pharmacological activity. The n-alkanols had greater fluidizing effects on the outer monolayer as compared to the inner monolayer of SPMVPL, even though these selective effects tended to become weaker as the carbon chain length increased. Thus, it has been proven that n-alkanols exhibit selective rather than nonselective fludizing effects within transbilayer domains of SPMVPL.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.337-343
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• 2009

To apply to novel two-interconnected fluidized beds system for selective solid circulation, a solid separator and a solid circulation system were developed. The solid separation rate increased as the gas velocity through the solid injection nozzle, solid height, and diameter of solid injection nozzle increased. However, the effect of the fluidization velocity was negligible. Coarse($212{\sim}300{\mu}m$) and fine($63{\sim}106{\mu}m$) particles were separated using the solid separator and the solid separation rate was ranged from 66 to 453 g/min. The solid circulation rate increased as the gas velocity through the solid injection nozzle, solid height, and the number of solid intake holes increased. However, the effect of the fluidization velocity was negligible. Fine particle was circulated using the solid circulation system and the solid circulation rate was ranged from 65 to 390 g/min. We also proposed two interconnenced fluidized beds system for selective solid circulation equipped with the developed solid separator and the solid circulation system. Long-term operation of continuous solid circulation up to 20 hours has been performed to check feasibility of stable operation. The pressure drop profiles in two beds and the solid separation rate were maintained steadily, and therefore, we could conclude that solid circulation was smooth and stable.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.355-361
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• 2009

Effects of operating variables on solid separation rate in two-interconnected fluidized beds system for selective solid circulation have been investigated. Coarse(212~300 or $425{\sim}600{\mu}m$) and fine($63{\sim}106{\mu}m$) particles were separated using the solid separator and the solid separation rate was ranged from 66 to 987 g/min. The solid separation rate increased as the gas velocity through the solid injection nozzle, solid height, diameter of solid injection nozzle, particle size of coarse particles, aperture of the solid separator, and weight fraction of fines in the solid mixture increased. However, the effect of the fluidization velocity was negligible.

• The Korean Journal of Pharmacology
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• v.28 no.2
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• pp.191-199
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• 1992

Selective quenching of 1,6-diphenyl-1,3,5-hexatriene (DPH) by trinitrophenyl groups was utilized to examine the transbilayer fluidity asymmetry of model membranes of total lipids (SPMVTL) extracted from synaptosomal plasma membrane vesicles (SPMV). The polarization (P), anisotropy (r), limiting anisotropy $(r_{\infty})$, and order parameter (S) of DPH in the inner monolayer were 0.031, 0.025, 0.033, and 0.070, respectively, greater than calculated for the outer monolayer of SPMVTL. Selective quenching of DPH by trinitrophenyl groups was also utilized to examine the effects of n-alkanols on the individual monolayer structure of SPMVTL. n-Alkanols fluidized the hydrocarbon region of bulk SPMVTL, and the potencies of n-alkanols up to 1-nonanol increased with carbon chain length. It appears that the potencies in bilayer fluidization increase by 1 order of magnitude as the carbon chain length increases by two carbon atoms. The cut-off phenomenon was reached at 1-decanol, where further increase in hydrocarbon length resulted in a decrease in pharmacological activity. The n-alkanols had greater fluidizing effects on the outer monolayer as compared to the inner monolayer of SPMVTL, even though these selective effects tended to become weaker as carbon chain length increased. Thus, it has been proven that n-alkanols exhibit selective rather than nonselective fluidizing effects within transbilayer domains of SPMVTL.