bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of 5‐HT receptors on human pulmonary artery and vein: functional and binding studies
Authors: Cortijo Julio , Martí‐Cabrera Miguel , Bernabeu Eva , Domènech Teresa , Bou Josep , Fernández Andrés G. , Beleta Jorge , Palacios José M. , Morcillo Esteban J. 
Published: January 2005

This study aimed to investigate the 5‐hydroxytryptamine (5‐HT) receptors mediating contraction of ring preparations isolated from human pulmonary arteries and veins. In functional studies, the responses to 5‐HT, sumatriptan, ergotamine, serotonin‐O‐carboxymethyl‐glycyl‐tyrosinamide (SCMGT), α‐methyl 5‐HT (α‐Me) and 2‐methyl 5‐HT (2‐Me) were studied with WAY100635, GR127935, ritanserin, zacopride and SB204070 as antagonists.
All agonists produced concentration‐dependent contractions of human pulmonary artery and vein preparations. The order of potency (−log EC50 values) was ergotamine (6.88)>5‐HT (6.41)SCMGT (6.20)=sumatriptan (6.19) α‐Me (6.04) in the artery, and ergotamine (7.84)>5‐HT (6.96)>sumatriptan (6.60)=α‐Me (6.56)>SCMGT (6.09) in the vein. The potency of each agonist, except for SCMGT, was greater in vein than in artery preparations. Contractile responses to 5‐HT were similar in intact and endothelium‐denuded preparations but responses to sumatriptan were enhanced in artery rings without endothelium.
GR127935 (1 nM to 0.5 μM) produced an unsurmountable antagonism of the response to 5‐HT, sumatriptan, ergotamine and SCMGT. Ritanserin (1 nM to 1 μM) also reduced the maximum contractile responses to 5‐HT, ergotamine and α‐Me in artery and vein preparations without affecting those to sumatriptan and SCMGT. In endothelium‐denuded preparations, surmountable antagonism of sumatriptan by GR127935 (in the presence of ritanserin) and of α‐Me by ritanserin (in the presence of GR127935) allowed for the calculation of the apparent pKB values of GR127935 (9.17±0.11 in artery and 9.11±0.05 in vein) and ritanserin (8.82±0.09 in artery and 8.98±0.12 in vein).
WAY100635 (1 nM to 1 μM), zacopride (1 nM to 1 μM), or SB204070 (1 nM) did not significantly alter the concentration‐response curves for 5‐HT, sumatriptan, ergotamine, SCMGT or 2‐Me in human pulmonary artery or vein thus indicating that 5‐HT1A, 5‐HT3 and 5‐HT4 receptors are presumably not involved in the contractile response to these agonists.
Binding studies using selective radioligands for different 5‐HT receptors could not detect the presence of 5‐HT1A receptor binding in human pulmonary blood vessels whereas the 5‐HT1B/1D radioligand [3H]‐5‐CT significantly labelled a population of specific binding sites in both vessel types. The presence of 5‐HT2A receptors could also be inferred from the level of binding of [3H]‐ketanserin to membranes obtained from human pulmonary vessels, although significance could not be reached for arteries. 5‐HT4 specific receptor binding was scarce in veins and absent in the case of arteries.
These findings indicate that the human pulmonary artery and vein have a mixed functional population of 5‐HT1B/1D and 5‐HT2A receptors mediating the contractile response to 5‐HT which is consistent with results of the binding studies.
Tumour necrosis factor‐α expression and cell recruitment in Sephadex particle‐induced lung inflammation: effects of dexamethasone and cyclosporin A
Authors: Williams Cara M. M. , Smith Lance , Flanagan Brian F. , Steve Clegg L. , Coleman John W. 
Published: January 2005

Tumour necrosis factor‐α (TNF‐α) is a cytokine with diverse properties consistent with a possible role in inflammatory disease. We investigated whether TNF‐α is induced during the progression of lung inflammation elicited by a particulate non‐antigenic stimulus, and whether pharmacological control of TNF‐α expression influences recruitment of specific inflammatory cell types.
A single intravenous injection of Sephadex particles into rats led to extensive granulomatous inflammation in lung alveolar and bronchial tissue that peaked in intensity after 24–72 h. Mononuclear cells were the principal component of granulomas, but neutrophils and eosinophils were also abundant. Numbers of mononuclear cells, neutrophils and eosinophils recovered by bronchoalveolar lavage (BAL) peaked at 72 h, 48 h and 72 h, respectively.
Messenger RNA encoding TNF‐α was induced in lung epithelial cells, lung granulomas and BAL cells 6 h after Sephadex administration and remained elevated for 72 h before declining to baseline by 7 days. In BAL cell populations TNF‐α protein was localized to mononuclear cells at all times points pre‐ and post‐Sephadex administration.
Treatment of rats with dexamethasone significantly reduced the Sephadex‐induced recruitment of mononuclear cells, neutrophils and eosinophils into the bronchoalveolar cavity, and significantly reduced TNF‐α mRNA expression by BAL cells.
Treatment of rats with cyclosporin A was without effect on Sephadex‐induced elevations of mononuclear cell numbers and expression of TNF‐α, but did reduce significantly recruitment of neutrophils and eosinophils to BAL cell populations.
These results show that a sequential asthma‐like recruitment of neutrophils, eosinophils and mononuclear cells into lung tissue can be induced by single exposure to a non‐antigenic stimulus. Pharmacological and histological studies reveal that mononuclear cell mobilization relates closely to induced TNF‐α expression, whereas mobilization of neutrophils and eosinophils appears secondary to expression of the cytokine.

British Journal of Pharmacology (1997) 122, 1127–1134; doi:10.1038/sj.bjp.0701515
Effect of mycophenolic acid on TNFα‐induced expression of cell adhesion molecules in human venous endothelial cells in vitro
Authors: Hauser Ingeborg A. , Johnson David R. , Thévenod Frank , Goppelt‐Strübe Margarete 
Published: January 2005

Mycophenolic acid (MPA) is an inhibitor of inosine‐5′‐monophosphate dehydrogenase and therefore interferes with cellular GTP biosynthesis. Recently, MPA has been used as an antiproliferative and immunosuppressive agent. In the present study, the effect of MPA on the expression of the endothelial cell adhesion molecules (CAMs), intercellular (I) CAM‐1, vascular (V) CAM‐1 and endothelial (E)‐selectin, was investigated in tumour necrosis factor‐α (TNFα)‐activated cultured human venous endothelial cells (EC).
Surface expression of CAMs was measured by flow cytometry and mRNA expression by Northern blot analysis. Transcriptional activation of CAMs by the nuclear factor NF‐κB was determined by an electromobility shift assay. The function of CAMs was studied by a static adhesion assay with human monocyte‐like undifferentiated U937 cells.
Pretreatment of TNFα‐ (5  ng ml−1, 12 h) activated EC with MPA (10 μM, 24 h) increased the binding of U937 cells, which had not been treated with MPA, by ∼amp;2 fold. MPA‐pretreatment of EC did not affect TNFα‐induced surface expression of ICAM‐1. However, VCAM‐1 and E‐selectin were increased 2–3 fold and remained elevated up to 24 h, by which time TNFα‐activated control EC had returned to baseline levels of expression. The effect of MPA on the surface expression of CAMs was half‐maximal at ∼amp;1 μM and required 12 h of pretreatment. Guanosine (0.3 mM), a precursor of GTP, did not prevent the effect of MPA on the expression of CAMs in TNFα‐activated EC.
Kinetics of mRNA expression of CAMs mirrored protein expression: mRNA for ICAM‐1 was unaffected, whereas TNFα‐induced mRNA expression for E‐selectin and VCAM‐1 was prolonged and increased by MPA. This effect was not due to increased transcription mediated by the nuclear transcription factor NF‐κB. However, half‐life for E‐selectin mRNA was increased 10 fold by MPA, whereas ICAM‐1 mRNA half‐life was unchanged.
The data demonstrate that apart from its antiproliferative effects on lymphocytes, MPA enhances TNFα‐induced VCAM‐1 and E‐selectin surface expression on EC by selectively increasing the mRNA‐stability of these cell adhesion molecules. This effect of MPA on EC appears to be independent from inhibition of inosine‐5′‐monophosphate dehydrogenase.
The regulation of mitogenesis and apoptosis in response to the persistent stimulation of α1‐adrenoceptors: a possible role of 15‐lipoxygenase
Authors: Nishio Eisuke , Watanabe Yasuhiro 
Published: January 2005

Activation of α1‐adrenoceptor stimulation regulates eicosanoid metabolism and growth in vascular smooth muscle cells (VSMCs). The purpose of this study was to investigate the functional implications of lipoxygenase pathway in α1‐adrenoceptor‐stimulated VSMCs growth through mutually exclusive biological functions, that is cell proliferation and cell death.
Phenylephrine (10 μM), a specific α1‐adrenoceptor agonist, enhanced [3H]‐thymidine incorporation by 300% above basal. Nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, caused 36 and 50% decrease in phenylephrine (10 μM)‐stimulated [3H]‐thymidine incorporation at concentrations of 1 μM and 10 μM respectively.
Inversely, treatment of phenylephrine (10 μM)‐stimulated VSMCs with NDGA induced DNA fragmentation in a dose‐dependent fashion. The level of induction of DNA fragmentation by NDGA was 225, 319 and 406% above the phenylephrine (10 μM)‐level at concentrations of 0.1 μM, 1 μM and 10 μM, respectively. This induction of DNA fragmentation was partially prevented by exogenous 15‐hydroxyeicosatetraenoic acid (15‐HETE). The inhibition of apoptosis was 53 and 63% at concentrations of 5 μM and 10 μM of 15HETE, respectively, as compared with phenylephrine (10 μM) in the presence of NDGA (10 μM).
Furthermore, we performed the time‐course analysis of Bcl‐2 protein expression in phenylephrine (10 μM)‐stimulated VSMCs. The expression of Bcl‐2 protein disappeared after a 2 h incubation in the presence of NDGA (10 μM), but remained stable after a 2 h incubation period in the absence of NDGA (10 μM).
These results suggest that the lipoxygenase pathway is involved in cell proliferation by preventing apoptosis through the level of Bcl‐2 protein expression.
Influence of olfactory bulbectomy and subsequent imipramine treatment on 5‐hydroxytryptaminergic presynapses in the rat frontal cortex: behavioural correlates
Authors: Grecksch Gisela , Zhou Dan , Franke Christian , Schröder Ulrike , Sabel Bernhard , Becker Axel , Huether Gerald 
Published: January 2005

Alterations of 5‐hydroxytryptaminergic mechanisms are thought to play a special role in the pathogenesis of depression and antidepressant treatments are assumed to restore these changes.
We have used one of the most reliable models of depression, the olfactory bulbectomized rat to study the long term consequences of this manipulation and of subchronic imipramine treatment on two parameters of 5‐hydroxytryptaminergic presynapses, 5‐hydroxytryptamine (5‐HT) transporter density and tryptophan hydroxylase apoenzyme concentration, in the frontal cortex as well as on active avoidance learning several weeks after bulbectomy.
The Bmax value of [3H]‐paroxetine binding and the concentration of the 5‐HT synthesizing enzyme were both significantly elevated in the frontal cortex of bulbectomized rats compared to sham‐operated controls.
Imipramine treatment, either by daily injections or by subcutaneous implantation of slow release imipramine‐containing polymers reduced the elevated tryptophan hydroxylase apoenzyme levels in the frontal cortex of bulbectomized, but not of sham‐operated control rats and restored the deficient learning performance of bulbectomized rats.
Both effects were more pronounced after continuous drug administration by imipramine‐releasing polymers compared to daily i.p. injections.
These findings indicate that bulbectomy leads to a compensatory 5‐hydroxytryptaminergic hyperinnervation of the frontal cortex. Chronic antidepressant treatment seems to attenuate the increased output of the 5‐hydroxytryptaminergic projections in the frontal cortex through the destabilization of the rate limiting enzyme of 5‐HT synthesis of the 5‐hydroxytryptaminergic nerve endings in this brain region.
Analogues of γ‐aminobutyric acid (GABA) and trans‐4‐aminocrotonic acid (TACA) substituted in the 2 position as GABAC receptor antagonists
Authors: Chebib Mary , Vandenberg Robert J. , Johnston Graham A. R. 
Published: January 2005

γ‐Aminobutyric acid (GABA) and trans‐4‐aminocrotonic acid (TACA) have been shown to activate GABAC receptors. In this study, a range of C2, C3, C4 and N‐substituted GABA and TACA analogues were examined for activity at GABAC receptors.
The effects of these compounds were examined by use of electrophysiological recording from Xenopus oocytes expressing the human ρ1 subunit of GABAC receptors with the two‐electrode voltage‐clamp method.
trans‐4‐Amino‐2‐fluorobut‐2‐enoic acid was found to be a potent agonist (KD=2.43 μm). In contrast, trans‐4‐amino‐2‐methylbut‐2‐enoic acid was found to be a moderately potent antagonist (IC50=31.0 μm and KB=45.5 μm). These observations highlight the possibility that subtle structural substitutions may change an agonist into an antagonist.
4‐Amino‐2‐methylbutanoic acid (KD=189 μm), 4‐amino‐2‐methylenebutanoic acid (KD=182 μm) and 4‐amino‐2‐chlorobutanoic acid (KD=285 μm) were weak partial agonists. The intrinsic activities of these compounds were 12.1%, 4.4% and 5.2% of the maximal response of GABA, respectively. These compounds more effectively blocked the effects of the agonist, GABA, giving rise to KB values of 53 μm and 101 μm, respectively.
The sulphinic acid analogue of GABA, homohypotaurine, was found to be a potent partial agonist (KD=4.59 μm, intrinsic activity 69%).
It was concluded that substitution of a methyl or a halo group in the C2 position of GABA or TACA is tolerated at GABAC receptors. However, there was dramatic loss of activity when these groups were substituted at the C3, C4 and nitrogen positions of GABA and TACA.
Molecular modelling studies on a range of active and inactive compounds indicated that the agonist/competitive antagonist binding site of the GABAC receptor may be smaller than that of the GABAA and GABAB receptors. It is suggested that only compounds that can attain relatively flat conformations may bind to the GABAC receptor agonist/competitive antagonist binding site.
Human vascular kinin receptors of the B2 type characterized by radioligand binding
Authors: Gessi S. , Rizzi A. , Calò G. , Agnello G. , Jorizzo G. , Mollica G. , Borea P. A. , Regoli D. 
Published: January 2005

The human umbilical vein responds to bradykinin (BK) with contractions that are mediated by B2 receptors. In the present study, the corresponding vascular smooth muscle B2 binding sites have been investigated.
[3H]‐BK, a full agonist labelled ligand, was used to demonstrate a single binding site giving a Kd value of 0.51±0.02 nM and a Bmax of 24±1 fmol mg−1 protein. Scatchard plots were linear (r=0.98) in the 0.05–5 nM range of concentrations. Non‐specific binding was found to be 30% of total binding.
Competition binding curves gave the following order of potency for various B2 receptor agonists: BK‐[Hyp3]‐BKLys‐BK>>[Aib7]‐BK>>>[desArg9]‐BK, which is typical of B2 receptors. There was no binding to B1 receptors since the selective B1 receptor ligand, Lys‐[desArg9]BK was inactive up to 10 μM (n=4).
Characterization of the binding site with antagonists, performed with three chemically distinct series of peptide and non‐peptide compounds, revealed a high affinity of Hoe 140 (D‐Arg‐[Hyp3,Thi5,D‐Tic7,Oic8]‐BK) (Ki 0.17 nM; n=4) which was more potent that FR 173657 ([(E)‐3‐(6‐acetamido‐3‐pyridyl)‐N‐[N‐[2,4‐dichloro‐3‐[(2‐methyl‐8‐quinolinyl)oxymethyl]phenyl]‐N‐methylaminocarbonylmethyl] acrylamide]) (Ki 1.94 nM; n=4), D‐Arg‐[Hyp3,D‐Phe7,Leu8]‐BK (Ki 256 nM; n=4) and Win 64338 (phosphonium, [[4[[2[[bis(cyclohexylamino)methylene]amino]‐3‐(2‐naphthalenyl)‐1‐oxopropyl]amino]phenyl]methyl]tributyl, chloride, monohydrochloride) (Ki 1,450 nM; n=4).
The present study describes and characterises B2 receptor binding sites in the vascular smooth muscle of the human umbilical vein. The binding assay appears to be suitable for studying new agonists or antagonists designed to activate or block the B2 receptor class that mediate the majority of the physiopathological effects of kinins in man.
Glucose‐lowering effect of BTS 67 582
Authors: Page T. , Bailey C. J. 
Published: January 2005

The hypoglycaemic effect of BTS 67 582 (1,1‐dimethyl‐2(2‐morpholinophenyl) guanidine fumarate) was studied in normal rats.
BTS 67 582 (100 mg kg−1, p.o.) acutely lowered basal plasma glucose concentrations: onset within 1 h, maximum decrease of >40% at 2–3 h, and partial return to euglycaemia by 5 h. Plasma insulin concentrations were increased: onset within 30 min, maximum increase 3 fold at 1–2 h; returning to normal by 5 h.
BTS 67 582 (100 mg kg−1) increased (by 56%) the rate of disappearance of plasma glucose during an intravenous glucose tolerance test, accompanied by a 51% increase in insulin concentrations.
During hyperglycaemic clamp studies BTS 67 582 (100 mg kg−1) increased glucose utilization 3 fold. This was associated with a 3 fold increase in insulin concentrations, even in the presence of adrenaline at a dosage which inhibits glucose‐induced insulin release.
When the insulin‐releasing effect of BTS 67 582 (100 mg kg−1) was inhibited by infusion of somatostatin, there was no effect on glycaemia.
Insulin‐dependent diabetic BB/S rats, which do not produce endogenous insulin, showed no effect of BTS 67 582 (100 mg kg−1) on plasma glucose concentrations in the presence or absence of exogenous insulin.
The results demonstrate an acute hypoglycaemic effect of BTS 67 582 which appears to result mainly from its potent insulin‐releasing action.
Spinal pharmacology of tactile allodynia in diabetic rats
Authors: Calcutt Nigel A. , Chaplan Sandra R. 
Published: January 2005

Rats develop tactile allodynia to stimulation of the plantar surface of the hindpaw with von Frey filaments within days of the onset of streptozotocin‐induced diabetes. This is prevented by insulin and alleviated by systemic lignocaine, but the aetiology is unknown.
Using indwelling lumbar intrathecal catheters to deliver pharmacological agents, we have investigated whether tactile allodynia in streptozotocin‐diabetic rats is dependent on mechanisms associated with spinal sensitization, by assessing the efficacy of agents that inhibit specific components of spinal nociceptive processing.
Dose‐dependent inhibition of tactile allodynia in diabetic rats was noted with the N‐type calcium channel antagonist SNX 239, the α2‐adrenoceptor agonist dexmedetomidine, the μ‐opioid receptor agonist morphine, the N‐methyl‐D‐aspartate (NMDA) receptor antagonist AP5 and the non‐NMDA receptor antagonist NBQX.
No effect on tactile allodynia was noted after intrathecal administration of the nitric oxide synthase inhibitor NG‐nitro‐L‐arginine methyl ester (L‐NAME), the cyclo‐oxygenase inhibitor ketorolac, the L‐type calcium channel inhibitor diltiazem or any vehicle.
These data suggest that the tactile allodynia of diabetic rats involves spinal glutamatergic pathways but is not associated with spinal release of nitric oxide or prostaglandins.
Cortistatin increase of a potassium conductance in rat locus coeruleus in vitro
Authors: Connor Mark , Ingram Susan L. , Christie MacDonald J. 
Published: January 2005

In this study we examined the effects of cortistatin, a putative endogenous ligand for somatostatin (SRIF) receptors, on the membrane properties of rat locus coeruleus (LC) neurones in vitro, by use of intracellular and whole cell patch clamp recording. We have compared the actions of cortistatin with those of SRIF and the SRIF analogue d‐Phe‐Cys‐Tyr‐d‐Trp‐Orn‐Thr‐Pen‐Thr‐NH2 (CTOP).
When LC neurones were voltage clamped to −60 mV, application of cortistatin caused an outward current in all cells examined (n=44), with a pEC50 of 6.62. SRIF also caused an outward current in all cells examined (n=43), with a pEC50 of 6.93.
The outward currents caused by cortistatin in 2.5 mm extracellular K+ reversed polarity at −106 mV, very close to the predicted K+ reversal potential of −105 mV. Increasing extracellular K+ to 10.5 mm resulted in a shift of the reversal potential of +38 mV, a shift consistent with a K+ conductance. The conductance activated by cortistatin showed mild inward rectification.
Continuous application of a high concentration of SRIF (1 μm) resulted in a decrease of the outward current to a steady level of 49% of the maximum response, with a t1/2 of 131 s. Application of a high concentration of cortistatin (3 μm) during the desensitized portion of the SRIF response did not result in any further outward current. Continuous application of a high concentration of cortistatin (10 μm) resulted in a decrease of the outward current to a steady level of 42% of the maximum response with a t1/2 of 114 s. Application of a high concentration of SRIF (3 μm) during the desensitized portion of the cortistatin response produced only a small outward current.
Continuous application of cortistatin (3 μm) also resulted in a decrease of the outward current (by 43%, t1/2 of 136 s) and application of a high concentration of CTOP (10 μm) during the desensitized portion of the cortistatin response did not produce any outward current. Continuous application of a high concentration of CTOP (10 μm) resulted in a decrease of the outward current to a steady level of 70% of the maximum response with a t1/2 of 143 s. Application of a high concentration of cortistatin (3 μm) during the desensitized portion of the CTOP response did not result in any further outward current.
The actions of cortistatin (300 nm–10 μm) were not affected by the opioid antagonist naloxone (10 μm). Application of met‐enkephalin during the desensitized portion of the response to a high concentration of cortistatin (3 μm) produced an outward current similar to that produced by met‐enkephalin application alone.
Thus cortistatin efficaciously activates an inwardly rectifying K+ conductance in LC neurones. These actions appear to be mediated by a population of SRIF receptors, at which CTOP is also an agonist. Cortistatin does not appear to be a ligand for μ‐opioid receptors in rat LC neurons.