NMDA receptor antibodies predict adverse neurological outcome after cardiac surgery in high-risk patients.

Background And Purpose: The goal of this study was to compare the predictive ability of S100B, N-methyl-D-aspartate (NMDA) receptor antibodies (NR2Ab) and C-reactive protein (CRP) for neurological deficits after cardiac surgery with cardiopulmonary bypass (CPB).

Methods: We investigated 557 high-risk adult patients who underwent coronary artery or valve replacement surgery using CPB as a substudy of a prospective, blinded, multicenter clinical trial. Serum concentrations of S100B (n=513 patients), NR2Ab (n=398) and CRP (n=510) were measured preoperatively, 24 and 48 hours after CPB.

Radioiodinated azide and isothiocyanate derivatives of cocaine for irreversible labeling of dopamine transporters: synthesis and covalent binding studies.

Two novel N-substituted-3beta-phenyltropane alkaloids have been labeled with iodine-125 for use as irreversible probes of dopamine transporter (DAT) binding sites. One contains an iodoaryl azide moiety for photolabeling, while the other bears an iodoaryl isothiocyanate for direct conjugation. Both radioligands were prepared in a one-flask procedure by electrophilic radioiodination of the corresponding aniline under no-carrier-added conditions, followed either by diazotization and treatment with sodium azide, or by addition of thiophosgene under basic conditions.

Affinity labeling the dopamine transporter ligand binding site.

Photoaffinity labeling is a positive function approach that has been used in an effort to identify the cocaine-binding site on the dopamine transporter (DAT). Radioactive and non-radioactive analogs of cocaine and other dopamine uptake blockers are used to irreversibly label the DAT ligand-binding site and the protein is subjected to chemical or enzymatic treatments that cleave at specific amino acid residues. Analysis of cleavage products from radioactively photolabeled DAT using epitope-specific immunoprecipitation, gel electrophoresis, and autoradiography has identified the site of origin in the primary sequence of labeled fragments as small as 4 kDa.

Novel azido and isothiocyanato analogues of [3-(4-phenylalkylpiperazin-1-yl)propyl]bis(4-fluorophenyl)amines as potential irreversible ligands for the dopamine transporter.

Potential irreversible ligands were prepared, based on a series of 3-(1-piperazinyl)propyl-N,N-bis(4-fluorophenyl)amines, as molecular probes for the dopamine transporter (DAT). Both azido- and isothiocyanato-substituted phenylalkyl analogues were synthesized and evaluated for displacement of [(3)H]WIN 35 428 in rat caudate putamen tissue. All of the analogues showed moderate binding potencies at the DAT.

Microdialysis of dopamine interpreted with quantitative model incorporating probe implantation trauma.

Although microdialysis is widely used to sample endogenous and exogenous substances in vivo, interpretation of the results obtained by this technique remains controversial. The goal of the present study was to examine recent criticism of microdialysis in the specific case of dopamine (DA) measurements in the brain extracellular microenvironment. The apparent steady-state basal extracellular concentration and extraction fraction of DA were determined in anesthetized rat striatum by the concentration difference (no-net-flux) microdialysis technique.

Dual-electrode voltammetry of catecholamine transport: simultaneous monitoring of uptake and efflux.

Dual-electrode voltammetry is used to characterize induced efflux of dopamine by m-tyramine via the norepinephrine transporter, stably expressed in a LLC-PK(1) cell line. A rotating disk electrode measures solely the dopamine oxidation current, while a stationary electrode held at a higher potential measures both the dopamine and m-tyramine concentrations. The ratio of the rate of dopamine efflux to the rate of m-tyramine uptake exhibits a hyperbolic dependence on initial dopamine concentration (half-maximal initial concentration of 4 microM) and is independent of the concentration of m-tyramine used to induce efflux for the two concentrations of tyramine tested (3 and 10 microM).

Increase in accumbal dopaminergic transmission correlates with response cost not reward of hypothalamic stimulation.

Rats were trained to lever-press for intracranial self-stimulation (ICSS) of the lateral hypothalamus on either a fixed ratio (FR) 1 or 10 schedule. Their brains were removed after a 20 min session and tissue punches taken from the nucleus accumbens, olfactory tubercle, anterior striatum, or central striatum. These punches were assayed for content of dopamine (DA) and the major DA metabolite DOPAC.

Endogenous opioids in dopaminergic cell body regions modulate amphetamine-induced increases in extracellular dopamine levels in the terminal regions.

Opioid antagonists attenuate behavioral effects of amphetamine and amphetamine-induced increases in extracellular dopamine levels in nucleus accumbens and striatum of rats but do not alter those effects of cocaine. This study was performed to determine 1) if the effect of opioid antagonists on the dopamine response to amphetamine is mediated in either the terminal or cell body region of the nigrostriatal and mesolimbic pathways, and 2) if the enkephalinase inhibitor thiorphan, which slows degradation of endogenous opioid peptides, increases the dopamine response to amphetamine but not to cocaine. Microdialysis probes were placed either into a dopaminergic terminal region or into both a terminal and cell body region of rats.