bluuebunny/crossref_metadata_2025_split huggingface dataset:
5‐HT2B receptors play a key role in mediating the excitatory effects of 5‐HT in human colon in vitro
Authors: Borman R A , Tilford N S , Harmer D W , Day N , Ellis E S , Sheldrick R L G , Carey J , Coleman R A , Baxter G S 
Published: January 2005

5‐Hydroxytryptamine (5‐HT) is known to produce a number of different effects in the gastrointestinal tract of various species, and has been proposed to play a key role in a number of intestinal disorders in man, including irritable bowel syndrome (IBS), although the receptors involved have yet to be established. The aim of the present study was to investigate the distribution and function of 5‐HT2B receptors in human colon, and to establish their possible role in the aetiology of IBS.
The distribution of 5‐HT2B receptor mRNA and protein were investigated by quantitative RT – PCR, Western analysis and immunocytochemistry. High levels of both mRNA and protein for 5‐HT2B receptors were found throughout the human gastrointestinal tract, and in particular in colon, where 5‐HT2B receptors were found predominantly in the longitudinal and circular smooth muscle layers within the muscularis externa, and in the myenteric nerve plexus lying between these two layers.
Electrical field stimulation of longitudinal muscle preparations of human colon mounted in organ baths resulted in neuronally‐mediated contractile responses, that were significantly potentiated by application of 5‐HT (up to 10−7 M), with a pEC50 of 8.2±0.1 (n=49 donors). The response to 5‐HT was inhibited by a number of selective 5‐HT2B receptor antagonists.
This study has shown for the first time that, in contrast to animal studies, the excitatory effects of 5‐HT in human colon are mediated by 5‐HT2B receptors. It is proposed that these receptors contribute to the putative 5‐HT‐induced colonic smooth muscle hypersensitivity associated with IBS.

British Journal of Pharmacology (2002) 135, 1144–1151; doi:10.1038/sj.bjp.0704571
Effect of SEA0400, a novel inhibitor of sodium‐calcium exchanger, on myocardial ionic currents
Authors: Tanaka Hikaru , Nishimaru Kazuhide , Aikawa Tokiko , Hirayama Wataru , Tanaka Yoshio , Shigenobu Koki 
Published: January 2005

The effects of 2‐[4‐[(2,5‐difluorophenyl) methoxy]phenoxy]‐5‐ethoxyaniline (SEA0400), a newly synthesized Na+‐Ca2+ exchanger (NCX) inhibitor, on the NCX current and other membrane currents were examined in isolated guinea‐pig ventricular myocytes and compared with those of 2‐[2‐[4‐(4‐nitrobenzyloxy) phenyl]ethyl]isothiourea (KB‐R7943). SEA0400 concentration‐dependently inhibited the NCX current with a 10 fold higher potency than that of KB‐R7943; 1 μM SEA0400 and 10 μM KB‐R7943 inhibited the NCX current by more than 80%. KB‐R7943, at 10 μM, inhibited the sodium current, L‐type calcium current, delayed rectifier potassium current and inwardly rectifying potassium current by more than 50%, but SEA0400 (1 μM) had no significant effect on these currents. These results indicate that SEA0400 is a potent and highly selective inhibitor of NCX, and would be a powerful tool for further studies on the role of NCX in the heart and the therapeutic potential of its inhibition.British Journal of Pharmacology (2002) 135, 1096–1100; doi:10.1038/sj.bjp.0704574
Naloxone prevents cell‐mediated immune alterations in adult mice following repeated mild stress in the neonatal period
Authors: Loizzo Alberto , Loizzo Stefano , Lopez Luisa , D'Amore Antonio , Renzi Paolo , Spampinato Santi , Di Carlo Simonetta , Bacosi Antonella , Zuccaro Piergiorgio , Pacifici Roberta 
Published: January 2005

Mild stress plus mild pain (solvent injection) applied daily to neonatal mice induces hormonal, behavioural and metabolic changes perduring in the adult life.
We investigated whether daily mild stress to neonatal mice induces also long‐term defined changes of immune response, and whether immune changes are prevented through repeated administration of the opioid antagonist naloxone.
Mild stress plus solvent injection administered from birth to the 21st postnatal day causes not only behavioural and metabolic changes, but also long‐term (up to 110 days of life) splenocytes modifications, consisting in: increased release of the Th‐1 type cytokines interleukin‐2 (IL‐2) (from an average of 346 to 788 pg ml−1), interferon‐γ (from 1770 to 3942) and tumour necrosis factor‐α (from 760 to 1241); decreased release of the Th‐2 type cytokines IL‐4 (from 49.1 to 28.4) and IL‐10 (from 1508 to 877). Moreover, enhanced natural killer‐cell activity; enhanced proliferative splenocytes properties in resting conditions and following phytohemoagglutinin and concanavalin‐A stimulation are observed. Immunological, behavioural and metabolic changes are prevented by the opioid antagonist (−)naloxone (1 mg kg−1 per day s.c., administered instead of solvent) but not by the biologically inactive enantiomorph (+)naloxone.
In conclusion, endogenous opioid systems sensitive to naloxone are involved in long‐lasting enhancement of the Th‐1 type cytokines and cell‐mediated immunological response caused by repeated mild stress administered postnatally.

British Journal of Pharmacology (2002) 135, 1219–1226; doi:10.1038/sj.bjp.0704577
Characterization of the discriminable stimulus produced by 2‐BFI: effects of imidazoline I2‐site ligands, MAOIs, β‐carbolines, agmatine and ibogaine
Authors: MacInnes Nicholas , Handley Sheila L 
Published: January 2005

The molecular nature and functions of the I2 subtype of imidazoline binding sites are unknown but evidence suggests an association with monoamine oxidase (MAO). Rats can distinguish the selective imidazoline I2‐site ligand 2‐BFI from vehicle in drug discrimination, indicating functional consequences of occupation of these sites. We have used drug discrimination to investigate the nature of the discriminable stimulus, especially in relation to MAO inhibition.
Following training to distinguish 2‐BFI 7 mg kg−1 i.p. from saline vehicle in two‐lever operant‐chambers, male Hooded Lister rats underwent sessions where test substances were given instead and the proportion of lever presses on the 2‐BFI‐associated lever (substitution) recorded.
2‐BFI; its cogeners BU216, BU224, BU226 and LSL60101; the reversible MAO‐A inhibitors moclobemide and RO41‐1049; the β‐carbolines harmane, norharmane and harmaline which also reversibly inhibit MAO‐A, and the anti‐addictive substance ibogaine exhibited potent, dose‐dependent substitution for 2‐BFI.
Agmatine, and LSL60125 substituted at one dose only. The reversible MAO‐B inhibitors lazabemide and RO16‐1649; the σ2‐site ligand SKF10,047 and the I2A‐site ligand, amiloride, failed to substitute. The irreversible inhibitor of MAO, deprenyl, substituted for 2‐BFI while clorgyline did not.
These results suggest imidazoline I2 site ligands produce a common discriminable stimulus that appears associated with reversible inhibition of MAO‐A rather than MAO‐B, possibly through increases in extracellular concentration of one or more monoamines. Ibogaine exhibits a commonality in its subjective effects with those of I2‐site ligands.

British Journal of Pharmacology (2002) 135, 1227–1234; doi:10.1038/sj.bjp.0704579
Kainic acid‐induced neuronal cell death in cerebellar granule cells is not prevented by caspase inhibitors
Authors: Verdaguer Ester , García‐Jordà Elvira , Jiménez Andrés , Stranges Alessandra , Sureda Francesc X , Canudas Anna M , Escubedo Elena , Camarasa Jordi , Pallàs Mercè , Camins Antoni 
Published: January 2005

We examined the role of non‐NMDA receptors in kainic acid (KA)‐induced apoptosis in cultures of rat cerebellar granule cells (CGCs). KA (1 – 500 μM) induced cell death in a concentration‐dependent manner, which was prevented by NBQX and GYKI 52466, non‐NMDA receptor antagonists. Moreover, AMPA blocked KA‐induced excitotoxicity, through desensitization of AMPA receptors.
Similarly, KA raised the intracellular calcium concentration of CGCs, which was inhibited by NBQX and GYKI 52466. Again, AMPA (100 μM) abolished the KA (100 μM)‐induced increase in intracellular calcium concentration.
KA‐induced cell death in CGCs had apoptotic features, which were determined morphologically, by DNA fragmentation, and by expression of the prostate apoptosis response‐4 protein (Par‐4).
KA (500 μM) slightly (18%) increased caspase‐3 activity, which was strongly enhanced by colchicine (1 μM), an apoptotic stimulus. However, neither Z‐VAD.fmk, a pan‐caspase inhibitor, nor the more specific caspase‐3 inhibitor, Ac‐DEVD‐CHO, prevented KA‐induced cell death or apoptosis. In contrast, both drugs inhibited colchicine‐induced apoptosis.
The calpain inhibitor ALLN had no effect on KA or colchicine‐induced neurotoxicity.
Our findings indicate that colchicine‐induced apoptosis in CGCs is mediated by caspase‐3 activation, unlike KA‐induced apoptosis.

British Journal of Pharmacology (2002) 135, 1297–1307; doi:10.1038/sj.bjp.0704581
Commentary on Neostigmine Interactions with Non steroidal Anti‐inflammatory Drugs by Miranda et al.
Authors: Tallarida Ronald J 
Published: January 2005

The article by Miranda et al. presents data showing significant synergism between NEO and certain NSAIDs administered i.p. in the mouse. Their conclusions follow from isobolar analysis accompanied by statistical confidence limits that show significant differences between the additive (expected) and experimental potencies. This commentary discusses the features of the graphical method of analysis and points out other experimental designs and the methods used to analyse them.British Journal of Pharmacology (2002) 135, 1589–1590; doi:10.1038/sj.bjp.0704600
Rolipram inhibits leukocyte‐endothelial cell interactions in vivo through P‐ and E‐selectin downregulation
Authors: Sanz María‐Jesús , Alvarez Angeles , Piqueras Laura , Cerdá Miguel , Issekutz Andrew C , Lobb Roy R , Cortijo Julio , Morcillo Esteban J 
Published: January 2005

Rolipram, a selective phosphodiesterase (PDE) type 4 inhibitor, was used to characterize leukocyte recruitment mechanisms in models of acute and subacute inflammation. Intravital microscopy within the rat mesenteric microcirculation was employed.
Mesentery superfusion with PAF (0.1 μM) induced a significant increase in leukocyte rolling flux, adhesion and emigration at 60 min. Rolipram pretreatment, markedly inhibited these parameters by 100, 95 and 95% respectively.
Similar effects were observed when the mesentery was superfused with LPS (1 μg ml−1) for the same time period and these leukocyte parameters were nearly abrogated by rolipram pretreatment.
LPS exposure of the mesentery for 4 h caused a greater increase in leukocyte rolling flux, adhesion and emigration which were inhibited by rolipram administration by 51, 71 and 81% respectively.
Immunohistochemistry revealed a significant increase in P‐selectin expression after 60 min superfusion with PAF which was attenuated by rolipram.
LPS exposure of the mesentery for 4 h caused a significant increase in P‐ and E‐selectin, intercellular adhesion molecule‐1 (ICAM‐1) and vascular cell adhesion molecule‐1 (VCAM‐1) expression. Rolipram pretreatment down‐regulated both P‐ and E‐selectin expression but had no effect on ICAM‐1 and VCAM‐1 expression.
Significant increases in plasma cyclic AMP levels were detected at 4.5 h after rolipram administration.
In conclusion, we have demonstrated that rolipram is a potent in vivo inhibitor of leukocyte‐endothelial cell interactions. The effects observed are mediated through endothelial P‐ and E‐selectin downregulation. Therefore, selective PDE‐4 inhibitors may be useful in the control of different inflammatory disorders.

British Journal of Pharmacology (2002) 135, 1872–1881; doi:10.1038/sj.bjp.0704644
NCX4016 (NO‐aspirin) reduces infarct size and suppresses arrhythmias following myocardial ischaemia/reperfusion in pigs
Authors: Wainwright Cherry L , Miller Ashley M , Work Lorraine M , Soldato Piero Del 
Published: January 2005

The effect of the nitro‐derivative of aspirin, NCX4016, was assessed on ischaemic ventricular arrhythmias and myocardial infarct size in anaesthetized pigs in comparison to native aspirin.
Pigs were given aspirin (10 mg kg−1; n=6), low dose NCX4016 (18.4 mg kg−1; n=6) or high dose NCX4016 (60 mg kg−1; n=7) orally for 5 days prior to coronary occlusion and reperfusion. None of the interventions had any effect on baseline haemodynamics prior to coronary occlusion in comparison to control pigs (n=9). Aspirin and high dose NCX4016 both prevented the generation of thromboxane A2 from platelets activated ex vivo with A23187 (30 μM), whereas all three interventions markedly attenuated platelet aggregation in response to collagen in whole blood in comparison to controls.
None of the drug interventions had any effect on the incidence of ventricular fibrillation (VF) during myocardial ischaemia (100% in all groups). However, 60 mg kg−1 NCX4016 significantly attenuated the total number of premature ventricular beats (PVB's) (62±16 vs 273±40 in control pigs; P<0.05) during the first 30 min of occlusion. The higher dose of NCX4016 also significantly reduced myocardial infarct size (22.6±3.7% of area at risk vs 53.0±2.8% of area at risk in control pigs; P<0.05).
These results suggest that the nitro‐derivative of aspirin, NCX4016, is an effective antiplatelet agent, which unlike aspirin also reduces the extent of myocardial injury following ischaemia and reperfusion.

British Journal of Pharmacology (2002) 135, 1882–1888; doi:10.1038/sj.bjp.0704646
Tachykinin NK1 and NK2 receptors mediate inhibitory vs excitatory motor responses in human isolated corpus cavernosum and spongiosum
Authors: Patacchini Riccardo , Barbagli Guido , Palminteri Enzo , Lazzeri Massimo , Turini Damiano , Maggi Carlo Alberto 
Published: January 2005

Motor effects produced by tachykinins were studied in human isolated corpus spongiosum and cavernosum. In quiescent preparations neurokinin A caused potent contractions (pD2=8.3 – 7.9 respectively) prevented by the NK2 receptor‐selective antagonist nepadutant, whereas [Sar9]SP sulfone and senktide (NK1 and NK3 receptor‐selective agonists) produced no effect or spare contractions. In KCl‐precontracted corpus spongiosum septide (pD2=7.1) and [Sar9]SP sulfone (pD2=7.7) produced tetrodotoxin‐resistant relaxations, abolished by the tachykinin NK1 receptor‐selective antagonist SR 140333. [Sar9]SP sulfone (1 μM) produced similar relaxations in precontracted corpus cavernosum. Electrical field stimulation (EFS) elicited tetrodotoxin‐sensitive relaxations, which were additive to those produced by [Sar9]SP sulfone. Nω‐nitro‐L‐arginine (L‐NOARG) totally prevented both [Sar9]SP sulfone‐ and EFS‐induced relaxations. These results show that tachykinin NK1 and NK2 receptors mediate opposite motor effects in human penile tissues, suggesting a possible modulatory role of tachykinins on smooth muscle tone in these organs.British Journal of Pharmacology (2002) 135, 1351–1354; doi:10.1038/sj.bjp.0704650
The sleep hormone oleamide modulates inhibitory ionotropic receptors in mammalian CNS in vitro
Authors: Coyne Leanne , Lees George , Nicholson Russell A , Zheng Jian , Neufield Katherine D 
Published: January 2005

We examine the sensitivity of GABAA and glycine receptors (same ionotropic superfamily) to oleamide. We address subunit‐dependence/modulatory mechanisms and analogies with depressant drugs.
Oleamide modulated human GABAA currents (α1β2γ2L) in oocytes (EC50, 28.94±s.e.mean of 1.4 μM; Maximum 216%±35 of control, n=4). Modulation of human α1 glycine homo‐oligomers (significant), was less marked, with a lower EC50 (P<0.05) than GABA receptors (EC50, 22.12±1.4 μM; Maximum 171%±30, n=11).
Only the hypnogenic cis geometric isomer enhanced glycine currents (without altering slope or maximal current, it reduced the glycine EC50 from 322 to 239 μM: P<0.001). Modulation was not voltage‐dependent or associated with a shift in Er.
β1 containing GABAA receptors (insensitive to many depressant drugs) were positively modulated by oleamide. Oleamide efficacy was circa 2× greater at α1β1γ2L than α1β2γ2L (P=0.007). Splice variation in γ subunits did not alter oleamide sensitivity.
cis‐9,10‐Octadecenoamide had no effect on the equilibrium binding of [3H]‐muscimol or [3H]‐EBOB to mouse brain membranes. It does not directly mimic GABA, or operate as a neurosteroid‐, benzodiazepine‐ or barbiturate‐like modulator of GABAA‐receptors.
The transport of [3H]‐GABA into mouse brain synaptoneurosomes was unaffected by high micromolar concentrations of cis‐9,10‐octadecenoamide. Oleamide does not enhance GABA‐ergic currents or prolong IPSCs by inhibiting GABA transport.
Oleamide is a non‐selective modulator of inhibitory ionotropic receptors. The sleep lipid exerts its effects indirectly, or at a novel recognition site on the GABAA complex.

British Journal of Pharmacology (2002) 135, 1977–1987; doi:10.1038/sj.bjp.0704651
A direct inhibitory action of prostaglandins upon ACTH secretion at the late stages of the secretory pathway of AtT‐20 cells
Authors: Wilson Mary L , Guild Simon B 
Published: January 2005

The mouse AtT‐20/D16‐16 anterior pituitary tumour cell line was used as a model system for the study of the effects of prostaglandins upon the late stages of the adrenocorticotrophin (ACTH) secretory pathway.
Calcium (1 nM – 100 μM), guanosine‐5′‐O‐(3‐thiotriphosphate) (GTP‐γ‐S) (1 – 100 μM) and mastoparan (1 and 10 μM) all stimulated ACTH secretion from permeabilized AtT‐20 cells in a concentration‐dependent manner. GTP‐γ‐S and mastoparan stimulated ACTH secretion from permeabilized cells in the absence of calcium. Co‐incubation with prostaglandins E1 and E2 (PGE1, PGE2) (10 μM) but not prostaglandin F2α (PGF2α) (10 μM) significantly inhibited calcium‐, GTP‐γ‐S and mastoparan‐evoked secretion by 30 – 50%.
The effects of PGE1 and PGE2 upon GTP‐γ‐S (100 μM)‐, calcium (10 μM)‐ and mastoparan (10 μM)‐evoked secretion were concentration‐dependent. PGE1 significantly inhibited GTP‐γ‐S‐ and calcium‐evoked secretion at concentrations of PGE1 above 1 μM but mastoparan‐evoked secretion only at the highest concentration of PGE1 investigated (10 μM). PGE2 was much more potent than PGE1 and significantly inhibited GTP‐γ‐S‐ and calcium‐evoked secretion at 10 nM and above and mastoparan‐evoked secretion above 1 μM.
The inhibitory effects of PGE1 and PGE2 upon calcium‐, GTP‐γ‐S‐ and mastoparan‐stimulated ACTH secretion from permeabilized cells were pertussis toxin (PTX) sensitive.
In intact cells PGE1, PGE2 and PGF2α (1 nM – 10 μM) acting singly had little or no effect upon ACTH secretion. However, only PGE2 (1 nM – 10 μM) significantly inhibited corticotrophin‐releasing factor‐41 (CRF‐41) (100 nM)‐evoked secretion in a concentration dependent manner.
The present study finds that prostaglandins of the E series exert an inhibitory action, via a pertussis toxin‐sensitive GTP‐binding (G)‐protein, in the late stages of the ACTH secretory pathway distal to the G‐exocytosis (Ge)/calcium point of control.

British Journal of Pharmacology (2002) 135, 1851–1858; doi:10.1038/sj.bjp.0704652
Inhibition of spontaneous acetylcholine secretion by 2‐chloroadenosine as revealed by a protein kinase inhibitor at the mouse neuromuscular junction
Authors: Hirsh Jody K , Silinsky Eugene M 
Published: January 2005

Previous studies have reported discrepancies in the potencies of A1 adenosine receptor agonists at mouse motor nerve terminals. In addition, conflicting results on the role of protein kinase A (PKA) in mediating the inhibitory effects of A1 receptor agonists have been published. We thus decided to investigate the possibility of endogenous control of adenosine receptor sensitivity by protein kinases, using a variety of protein kinase inhibitors in conjunction with the adenosine receptor agonist 2‐chloroadenosine (CADO).
CADO, at the concentration employed previously to study spontaneous ACh release in the mouse (1 μM), did not inhibit spontaneous ACh release in our experiments. However, a higher concentration of CADO (10 μM) produced highly statistically‐significant reductions in spontaneous ACh release.
In the presence of the non‐selective protein kinase inhibitor, H7 (50 μM), the potency of CADO was increased such that 1 μM CADO now reduced spontaneous quantal ACh release to approximately 63% of control.
Both H7, and the selective PKA inhibitor, KT5720 (500 nM) prevented increases in ACh release produced by CPT cyclic AMP (250 μM), suggesting these kinase inhibitors were blocking PKA. In contrast to H7, however, KT5720, did not reveal an inhibitory effect of 1 μM CADO. A number of other non‐selective PKA inhibitors also failed to increase the potency of CADO.
The results suggest that an endogenous H7‐sensitive process modulates the sensitivity of the mouse A1 adenosine receptor and that the inhibitory effects of CADO are independent of cyclic AMP accumulation or PKA inhibition.

British Journal of Pharmacology (2002) 135, 1897–1902; doi:10.1038/sj.bjp.0704653
Stimulation of protein kinase B and p70 S6 kinase by the histamine H1 receptor in DDT1MF‐2 smooth muscle cells
Authors: Dickenson John M 
Published: January 2005

Previous studies have shown that the histamine H1 receptor activates p42/p44 mitogen‐activated protein kinases (MAPK) in DDT1MF‐2 smooth muscle cells via a phosphatidylinositol 3‐kinase (PI‐3K)‐dependent pathway. In this study the effect of histamine H1 receptor stimulation on protein kinase B (PKB) and p70 S6 kinase, both of which are downstream targets of PI‐3K, has been investigated. Increases in PKB and p70 S6 kinase activation were monitored by Western blotting using phospho‐specific PKB (Ser473) and p70 S6 kinase (Thr421/Ser424) antibodies.
Histamine stimulated time and concentration‐dependent increases in the phosphorylation of PKB and p70 S6 kinase in DDT1MF‐2 cells. Both responses were completely inhibited by the histamine H1 receptor antagonist mepyramine and following pre‐treatment with pertussis toxin, to block Gi/Go protein dependent pathways.
The PI‐3K inhibitors wortmannin (IC50 5.9±0.5 nM) and LY 294002 (IC50 6.9±0.8 μM) attenuated the increase in PKB phosphorylation induced by histamine (100 μM) in a concentration‐dependent manner.
Histamine‐induced increases in p70 S6 kinase phosphorylation were partially sensitive to rapamycin (20 nM; 68% inhibition) but completely blocked by wortmannin (100 nM), LY 294002 (30 μM) and the MAPK kinase inhibitor PD 98059 (50 μM).
In summary, these data demonstrate that the histamine H1 receptor stimulates PKB and p70 S6 kinase phosphorylation in DDT1MF‐2 smooth muscle cells. However, functional studies revealed that histamine does not stimulate DDT1MF‐2 cell proliferation or attenuate staurosporine‐induced caspase‐3 activity. The challenge for future research will be to link the stimulation of these kinase pathways with the physiological and pathophysiological roles of the histamine H1 receptor.

British Journal of Pharmacology (2002) 135, 1967–1976; doi:10.1038/sj.bjp.0704664