Multiple binding sites for I-125 RTI-121 and other cocaine analogs in rat frontal cerebral cortex
Neurosciences & Neurology; localization; h-3 gbr-12935 binding; transporter; membranes; dopamine transporter; cocaine; nucleus-accumbens; norepinephrine transporter; medial prefrontal cortex; brain synaptosomes; glycosylation; human dopamine; reinforcing properties; RTI-121; self-stimulation; serotonin transporter; striatal
In an effort to identify novel binding sites for cocaine and its analogs, we carried out binding studies with the high-affinity and selective ligand [I-125]RTI-121 in rat frontal cortical tissue. Very low densities of binding sites were found. Saturation analysis revealed that the binding was to both high- and low-affinity sites. Pharmacological competition studies were carried out with inhibitors of the dopamine, norepinephrine, and serotonin transporters. The various transporter inhibitors inhibited the binding of 15 pM [I-125]RTI-121 in a biphasic fashion following a two-site binding model. The resultant data were complex and did not suggest a simple association with any single transporter. Correlational analysis supported the following hypothesis: [I-125] RTI-121 binds to known transporters and not to novel sites; these include dopamine, norepinephrine, and serotonin transporters. Immunoprecipitation of transporters photoaffinity labeled with [(125)] RTI-82 and subsequent analysis of SDS-page gels revealed the presence of authentic dopamine transporters in these samples; displacement of the photoaffinity label occurred with a typical dopamine transporter pharmacology. These data are compatible with the binding properties of RTI-181 and the presence of several known transporters in the tissue studied. Synapse 30:9-17, 1998. (C) 1998 Wiley-Liss, Inc.dagger
Boja J W; Carroll F I; Vaughan R A; Kopajtic T; Kuhar M J
Synapse
1998
1998-09
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1002/(sici)1098-2396(199809)30:1%3C9::aid-syn2%3E3.3.co;2-p" target="_blank" rel="noreferrer noopener">10.1002/(sici)1098-2396(199809)30:1%3C9::aid-syn2%3E3.3.co;2-p</a>
Castration differentially alters H-3 nisoxetine binding to norepinephrine uptake sites in olfactory bulb and frontal cortex of male rats
androgens; cerebral-cortex; chemical cues; conspecific odors; depression; dopamine; h-3 nisoxetine; hormone-releasing hormone; induced plasticity; locus-coeruleus; memory/recognition; Neurosciences & Neurology; norepinephrine transporter; olfaction; transporter; transporter messenger-rna; tyrosine-hydroxylase
In the present study, [H-3]nisoxetine binding to norepinephrine (NE) uptake sites and [H-3]norepinephrine uptake were investigated within olfactory bulb (OB) and frontal cortex homogenates from intact and castrated male rats. Statistically significant reductions in the number of [H-3] nisoxetine binding sites (B-max) were found in OB from the castrates, while significantly increased B-max values were obtained in the frontal cortex. Castration also significantly altered the affinity (K-d) of [H-3]nisoxetine binding in the frontal cortex, but not in the OB. Assessment of [H-3]norepinephrine uptake showed that in neither brain regions were there any statistically significant differences in K-m nor V-max between the castrated and intact male rats, indicating that the basal uptake process is not changed following castration in either of these brain areas. These results demonstrate the differential effects of castration upon [H-3]nisoxetine binding sites between the OB and frontal cortex. Such findings provide new evidence for one of the mechanisms by which androgens may modulate central noradrenergic activity. Synapse 31:250-255, 1999. (C) 1999 Wiley-Liss, Inc.
Shang Y L; Boja J W; Dluzen D E
Synapse
1999
1999-03
Journal Article
<a href="http://doi.org/10.1002/(sici)1098-2396(19990315)31:4%3C250::aid-syn2%3E3.3.co;2-q" target="_blank" rel="noreferrer noopener">10.1002/(sici)1098-2396(19990315)31:4%3C250::aid-syn2%3E3.3.co;2-q</a>