| 1. |
- Ploj, Karolina, et al.
(författare)
-
Effects of melanocortin receptor ligands on ethanol intake and opioid peptide levels in alcohol-preferring AA rats
- 2002
-
Ingår i: Brain Research Bulletin. - 0361-9230 .- 1873-2747. ; 59:2, s. 97-104
-
Tidskriftsartikel (refereegranskat)abstract
- Melanocortin (MC) peptides are suggested to play a role in opiate dependence, where they antagonise the addictive properties of opiates. To further study the involvement of the MCs in drug dependence, we analysed the effects of the MC(4)-receptor antagonist HS014 (1 nmol/rat), and the non-selective MC-receptor agonist MTII (1 nmol/rat), using i.c.v. administration, on ethanol intake in alcohol-preferring AA rats. The rats had access to ethanol during 40 days, resulting in a mean ethanol intake of 6.6 g/kg/day, before treatment. One group received only artificial cerebrospinal fluid solution. MTII caused a reduction in ethanol intake and ethanol preference, whereas HS014 was without effect. No effect on water intake was observed. A decrease in food intake was detected after MTII, whereas HS014 induced an increase in food intake. Analysis of dynorphin B and Met-enkephalin-Arg(6)Phe(7) immunoreactive levels revealed that MTII and HS014 altered opioid peptide levels in several brain areas and the pituitary gland of the rats with an established ethanol intake. This is the first report showing that manipulation of the MC-receptor system changes ethanol intake in chronically ethanol-drinking AA rats. In addition, manipulation of the MC system modulates ethanol-induced changes in opioid peptide levels.
|
|
| 2. |
- Wikberg, Erika, et al.
(författare)
-
A 2H nuclear magnetic resonance study of the state of water in neat silica and zwitterionic stationary phases and its influence on the chromatographic retention characteristics in hydrophilic interaction high-performance liquid chromatography
- 2011
-
Ingår i: Journal of Chromatography A. - : Elsevier. - 0021-9673 .- 1873-3778. ; 1218:38, s. 6630-6638
-
Tidskriftsartikel (refereegranskat)abstract
- (2)H NMR has been used as a tool for probing the state of water in hydrophilic stationary phases for liquid chromatography at temperatures between -80 and +4°C. The fraction of water that remained unfrozen in four different neat silicas with nominal pore sizes between 60 and 300Å, and in silicas with polymeric sulfobetaine zwitterionic functionalities prepared in different ways, could be determined by measurements of the line widths and temperature-corrected integrals of the (2)H signals. The phase transitions detected during thawing made it possible to estimate the amount of non-freezable water in each phase. A distinct difference was seen between the neat and modified silicas tested. For the neat silicas, the relationship between the freezing point depression and their pore size followed the expected Gibbs-Thomson relationship. The polymeric stationary phases were found to contain considerably higher amounts of non-freezable water compared to the neat silica, which is attributed to the structural effect that the sulfobetaine polymers have on the water layer close to the stationary phase surface. The sulfobetaine stationary phases were used alongside the 100Å silica to separate a number of polar compounds in hydrophilic interaction (HILIC) mode, and the retention characteristics could be explained in terms of the surface water structure, as well as by the porous properties of the stationary phases. This provides solid evidence supporting a partitioning mechanism, or at least of the existence of an immobilized layer of water into which partitioning could be occurring.
|
|
| 3. |
|
|
| 4. |
- Wikberg, Erika, et al.
(författare)
-
Grafting of silica with sulfobetaine polymers via aqueous reversible addition fragmentation chain transfer polymerization and its use as a stationary phase in HILIC
- 2009
-
Ingår i: Journal of Separation Science. - Weinheim : WILEY-VCH Verlag GmbH & Co. KGaA. - 1615-9306 .- 1615-9314. ; 32:12, s. 2008-2016
-
Tidskriftsartikel (refereegranskat)abstract
- Porous silica particles of 3 mum diameter and 100 A nominal pore size were first activated for vinylic polymerization by functionalization with 3-methacryloyloxypropyl trimethoxysilane (MAPTMS) and thereafter dressed with zwitterionic grafts of the sulfoalkylbetaine type in the "grafting through" fashion by polymerizing 3-(2-(N-methacryloyloxyethyl)-N,N-dimethylammonio)propane sulfonate (SPE), using either free radical polymerization or controlled reversible addition fragmentation chain transfer polymerization (RAFT). Particles polymerized using RAFT had a lower overall coating which seemed to be more evenly distributed in the pore volume. Both approaches resulted in columns with similar separation properties in HILIC mode.
|
|
| 5. |
|
|
