1.
Botros, Milad, et al.
(författare)
Endomorphins interact with the substance P (SP) aminoterminal SP (1-7) binding in the ventral tegmental area of the rat brain
2008
Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 29:10, s. 1820-1824
Tidskriftsartikel (refereegranskat) abstract
We have recently identified a specific binding site for the tachykinin peptide substance P (SP) fragment SP1-7 in the rat spinal cord. This site appeared very specific for SP1-7 as the binding affinity of this compound highly exceeded those of other SP fragments. We also observed that endomorphin-2 (EM-2) exhibited high potency in displacing SP1-7 from this site. In the present work using a [H-3]-labeled derivative of the heptapeptide we have identified and characterized [H-3]-SP1-7 binding in the rat ventral tegmental area (VTA). Similarly to the [H-3]-SP1-7 binding in the spinal cord the affinity of unlabeled SP1-7 to the specific site in VTA was significantly higher than those of other SP fragments. Further, the tachykinin receptor NK-1, NK-2 and NK-3 ligands showed no or negligible binding to the identified site. However, the mu-opioid peptide (MOP) receptor agonists DAMGO, EM-1 and EM-2 did, and significant difference was observed in the binding affinity between the two endomorphins. As recorded from displacement curves the affinity of EM-2 for the SP1-7 site was 4-5 times weaker than that for SP1-7 but about 5 times higher than that of EM-1. The opioid receptor antagonists naloxone and naloxonazine showed weak or negligible binding. it was concluded that the specific site identified for SP1-7 binding in the rat VTA is distinct from the MOP receptor although it exhibits high affinity for EM-2.
2.
Elfverson, Martin, et al.
(författare)
Neurosteroids allosterically modulate the ion pore of the NMDA receptor consisting of NR1/NR2B but not NR1/NR2A
2008
Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 372:2, s. 305-308
Tidskriftsartikel (refereegranskat) abstract
Neurosteroids are endogenously derived compounds, mediating rapid effects in the central nervous system. They participate in vital processes, including memory and learning, neuroplasticity, and neuroprotection in Alzheimer's disease. However, the mechanisms behind those effects remain to be elucidated. The neurosteroids pregnenolone sulphate (PS) and pregnanolone sulphate (3alpha5betaS) have recently been shown to allosterically alter the NMDA receptor in nanomolar concentrations. Those studies featured ifenprodil, which is a dirty drug, with affinity to many targets. In this study we compare the NMDA receptors in the hippocampus to recombinant NMDA receptors, using [3H]-MK-801 as radioligand. The results show that neurosteroids modulate the ifenprodil binding kinetics in a narrow concentration interval, addressing it to the NR2B subunit, since no effects were recorded at recombinant NR1/NR2A receptors. The effects were also seen as changes in the manner ifenprodil displaced or induced the dissociation of [3H]-MK-801. It indicates that the neurosteroidal effects indeed alter the ion pore of the NMDA receptor, why it is reasonable to believe that these findings have physiological relevance.
3.
Fransson, Rebecca, et al.
(författare)
Small peptides mimicking substance P (1-7) and encompassing a C-terminal amide functionality
2008
Ingår i: Neuropeptides. - : Elsevier BV. - 0143-4179 .- 1532-2785. ; 42:1, s. 31-37
Tidskriftsartikel (refereegranskat) abstract
Some of the biological effects demonstrated after administration of substance P (SP) in vivo can indirectly be attributed to the fragmentation of the undecapeptide to its N-terminal bioactive fragment SP1–7. This heptapeptide (H-Arg-Pro-Lys-Pro-Gln-Gln-Phe-OH) is a major bioactive metabolite from SP that frequently exerts similar biological effects as the parent peptide but also, in several cases, completely opposite actions. Specific binding sites for the heptapeptide SP1–7 that are separate from the SP preferred NK receptors have been identified. In this study we demonstrate that (a) the C-terminal part of the SP metabolite SP1–7 is most important for binding as deduced from an Ala scan and that a replacement of Phe7 for Ala is deleterious, (b) truncation of the N-terminal amino acid residues of SP1–7 delivers peptides with retained binding activity, although with somewhat lower binding affinities than SP1–7 and (c) a C-terminal amide group as a replacement for the terminal carboxy group of SP1–7 and for all of the truncated ligands synthesized affords approximately 5–10-fold improvements of the binding affinities.
4.
Ghasemzadeh, Nasim, et al.
(författare)
Highly selective artificial gel antibodies for detection and quantification of biomarkers in clinical samples : I. Spectrophotometric approach to design the calibration curve for the quantification
2008
Ingår i: Journal of Separation Science. - : Wiley. - 1615-9306 .- 1615-9314. ; 31:22, s. 3945-3953
Tidskriftsartikel (refereegranskat) abstract
High selectivity of a biomarker is a basic requirement when it is used for diagnosis, prognosis and treatment of a disease. The artificial gel antibodies, which we synthesise by a molecular imprinting method, have this property not only for proteins, but also for bioparticles, such as viruses and bacteria. However, diagnosis of a disease requires not only that the biomarker can be "fished out" from a body fluid with high selectivity, but also that its concentration in the sample can rapidly be determined and preferably by a simple technique. This paper deals primarily with the development of a spectrophotometric method, which is so simple and fast that it can be used with advantage in a Doctor's Office. The development of this method was not straight-forward. However, by modifications of the performance of these measurements we can now design standard curves in the form of a straight line, when we plot the true (not the recorded "apparent" absorption) against known protein concentrations. In an additional publication (see the following paper in this issue of JSS) we show an application of such a plot: determination of the concentration of albumin in serum and cerebrospinal fluid from patients with neurological disorders to investigate whether albumin is a biomarker for these diseases.
5.
Ghasemzadeh, Nasim, et al.
(författare)
Highly selective artificial gel antibodies for detection and quantification of biomarkers in clinical samples : II. Albumin in body fluids of patients with neurological disorders
2008
Ingår i: Journal of Separation Science. - : Wiley. - 1615-9306 .- 1615-9314. ; 31:22, s. 3954-3958
Tidskriftsartikel (refereegranskat) abstract
We have previously used the molecular-imprinting method for the synthesis of artificial gel antibodies, highly selective for various proteins. In the present work, we have synthesized artificial gel antibodies against human albumin with the aim to develop a simple and rapid procedure to measure the concentration of this protein in samples of clinical interest. The procedure, based on the design of a standard curve (see the preceding paper), was applied on a quantitative analysis of albumin in human plasma and cerebrospinal fluid (CSF). We found that our technique permitted detection of albumin in these body fluids with high precision and that the concentration of this protein was significantly enhanced in CSF from patients with amyotrophic lateral sclerosis (ALS), compared to control samples. This finding is in agreement with results from earlier studies, which confirms the validity of our analysis technique and suggests that the barrier permeability may be affected in ALS, perhaps also for other proteins. No enhancement in plasma levels of albumin was seen in patients with ALS, but rather a decrease. The results further indicate that our approach might also apply well to other biomarkers for the actual neurological disease and other disorders.
6.
Johansson, Tobias, et al.
(författare)
Molecular mechanisms for nanomolar concentrations of neurosteroids at NR1/NR2B receptors
2008
Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 324:2, s. 759-768
Tidskriftsartikel (refereegranskat) abstract
Neurosteroids are endogenous steroids acting in the central nervous system. They participate in synaptic plasticity, memory and learning, Alzheimer's disease, and certain drug reward. Some mechanisms behind these effects are thought to be nongenomic, e. g., they modulate the function of the N-methyl-D-aspartate (NMDA) receptor complex. In this study, we used a Chinese hamster ovary cell line stably transfected with NMDA receptor constituents NR1/NR2B, to investigate the effects of nanomolar concentrations of the neurosteroids pregnenolone sulfate (PS) and pregnanolone sulfate (3 alpha 5 beta S) on binding of the radioligand [H-3] ifenprodil. Neither of the steroids displaced [H-3] ifenprodil, but both induced a shift in its fit from one to two binding sites. The effects of the neurosteroids were also measured as changes in intracellular calcium ([Ca2+](i)) after glutamate stimulation. Although the steroids did not alter the response to glutamate, they influenced the extent of ifenprodil blockade of the receptor: PS increased and 3 alpha 5 beta S decreased this effect. The coincubation of several NMDA receptor ligands in the assay indicated that PS and 3 alpha 5 beta S act via different binding sites from those for glutamate, glycine, and dithiothreitol. Combining the two steroids revealed that they do not share a common binding site. In conclusion, these results substantiate previous evidence of the allosteric modulatory effect induced by PS and 3 alpha 5 beta S on NMDA receptors at nanomolar concentrations. The neurosteroid-mediated modulation of the receptor is also reflected in an altered glutamate stimulated [Ca2+](i), in response to ifenprodil.
7.
Skårberg, Kurt, et al.
(författare)
The development of multiple drug use among anabolic-androgenic steroid users : six subjective case reports
2008
Ingår i: Substance Abuse Treatment, Prevention, and Policy. - London : BioMed Central. - 1747-597X. ; 3, s. 24-
Tidskriftsartikel (refereegranskat) abstract
BACKGROUND: The inappropriate use of anabolic androgenic steroids (AAS) was originally a problem among athletes but AAS are now often used in nonsport situations and by patients attending regular addiction clinics. The aim of this study was to improve understanding of the development of multiple drug use in patients seeking treatment at an addiction clinic for AAS-related problems. METHODS: We interviewed six patients (four men and two women) with experience of AAS use who were attending an addiction clinic for what they believed were AAS-related problems. The patients were interviewed in-depth about their life stories, with special emphasis on social background, substance use, the development of total drug use and subjective experienced psychological and physical side effects. RESULTS: There was significant variation in the development of drug use in relation to social background, onset of drug use, relationship to AAS use and experience of AAS effects. All patients had initially experienced positive effects from AAS but, over time, the negative experiences had outweighed the positive effects. All patients were dedicated to excess training and took AAS in combination with gym training, indicating that the use of these drugs is closely related to this form of training. Use of multiple drugs was common either in parallel with AAS use or serially. CONCLUSIONS: The study shows the importance of understanding how AAS use can develop either with or without the concomitant use of other drugs of abuse. The use of AAS can, however, progress to the use of other drugs. The study also indicates the importance of obtaining accurate, comprehensive information about the development of AAS use in designing treatment programmes and prevention strategies in this area.
8.
Svensson, Anne-Lie, et al.
(författare)
Reversal of opiate-induced apoptosis by human recombinant growth hormone in murine foetus primary hippocampal neuronal cell cultures
2008
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 105:20, s. 7304-7308
Tidskriftsartikel (refereegranskat) abstract
Previous studies have shown that chronic opiates may inhibit cell growth and trigger apoptosis leading to impaired cognitive capabilities in both humans and other mammals. In contrast, growth hormone (GH) has been demonstrated to stimulate cell growth and counteract apoptosis. GH has also been shown to improve learning and memory in both human and rodents. In this work, we demonstrate that GH may reverse opiate-induced apoptosis in cells derived from prenatal mouse hippocampus. Primary hippocampal cell cultures derived from 16-day-old fetal mouse neurons were treated with morphine for 7 days during growth in the absence or presence of recombinant human GH (rhGH). The release of lactate dehydrogenase (LDH) into the culture media and the level of cleaved caspase-3 were measured. Results indicate that morphine (15 mu M) decreased the cell content in a concentration-dependent manner and increased LDH release and caspase-3 activity. Thus, fetal mouse neurons treated with morphine showed less viability compared with controls. Interestingly, the addition of rhGH (11 mu M) counteracted the morphine-induced effect on the cell density. Furthermore, the hormone attenuated the effects on LHD release and caspase-3 activity elicited by morphine. These results suggest that the hormone is capable of preventing or even repairing morphine-induced damage to hippocampal cells.
9.
Wallinder, Charlotta, et al.
(författare)
Selective angiotensin II AT2 receptor agonists : Benzamide structure–activity relationships
2008
Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 16:14, s. 6841-6849
Tidskriftsartikel (refereegranskat) abstract
In the investigation of the structure–activity relationship of nonpeptide AT2 receptor agonists, a series of substituted benzamide analogues of the selective nonpeptide AT2 receptor agonist M024 have been synthesised. In a second series, the biphenyl scaffold was compared to the thienylphenyl scaffold and the impact of the isobutyl substituent and its position on AT1/AT2 receptor selectivity was also investigated. Both series included several compounds with high affinity and selectivity for the AT2 receptor. Three of the compounds were also proven to function as agonists at the AT2 receptor, as deduced from a neurite outgrowth assay, conducted in NG108-15 cells.
