0000000000860663
AUTHOR
I. Weber
Effects of Different Opioid Receptor Antagonists on the Electrically-Evoked Release of Endogenous Dopamine from the Isolated Neural Lobe of the Rat Pituitary Gland in vitro.
Abstract Isolated neural lobes of the rat pituitary gland were incubated in Krebs-HEPES solution which contained the dopamine uptake inhibitor GBR 12921 and in some experiments additionally pargyline. The release of endogenous dopamine evoked by electrical stimulation of the pituitary stalk was determined by high-performance liquid chromatography with electrochemical detection. (+/-)- Naloxone increased the evoked dopamine release maximally by 440% (EC(50) 209 nM). The (+)-enantiomer of naloxone (up to 10 muM) did not affect the release of dopamine. The preferential kappa-opioid receptor antagonist MR 2266 increased the evoked dopamine release maximally by 135% (EC(50) 7 nM). MR 2267, the i…
Crystallizing polystyrene microgel colloids
Spherical microgel particles of sufficiently high degree of internal cross-linking and swollen in a good solvent in many respects behave quite similarly to hard-sphere colloids. Due to solvent uptake they can be refractive-index-matched and density-matched in suitable organic solvents. We present preliminary measurements of the crystallization kinetics of 1:10 cross-linked polystyrene microgel particles. We measured Bragg and small-angle light scattering of the solidifying shear melt. Two different scattering patterns, a set of Debye-Scherrer rings and a second ring pattern at small angles could be observed. We check for similarities and differences compared to previously investigated collo…