bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of alpha‐1 adrenoceptor subtypes in RNA and protein in rabbit eyes
Authors: Suzuki Fumiko , Taniguchi Takanobu , Nakamura Seigo , Akagi Yoshio , Kubota Chikara , Satoh Makoto , Muramatsu Ikunobu 
Published: January 2005

We investigated subtypes of alpha‐1 adrenoceptor (AR) in rabbit ocular tissues using reverse transcription‐polymerase chain reaction (RT – PCR), in situ hybridization (ISH) and binding studies.
Competitive RT – PCR assays specific for the subtypes of alpha‐1 AR revealed that the mRNA expression of alpha‐1a AR was dominant, and that of each alpha‐1b and alpha‐1d was less than 10% and 0.5% of total alpha‐1 ARs mRNA, respectively, in the iris, ciliary body, choroid and retina.
In alpha‐1a AR splice isoform‐specific RT – PCR assays, we found a distinct proportion of each isoform mRNA in the iris, ciliary body and choroid.
The results of the ISH assays for alpha‐1a AR subtype showed that hybridization signals were clearly observed in the iris dilator muscle and in the epithelium of the ciliary processes.
In binding studies, alpha‐1A AR was a dominant subtype in the iris, choroid and retina in contrast to the ciliary body that had more alpha‐1B than alpha‐1A AR subtype at protein level.

British Journal of Pharmacology (2002) 135, 600–608; doi:10.1038/sj.bjp.0704503
Desferrithiocin is a more potent antineoplastic agent than desferrioxamine
Authors: Kicic Anthony , Chua Anita C G , Baker Erica 
Published: January 2005

Desferrithiocin (DFT) is an orally effective Fe chelator, with a similar high affinity and selectivity for Fe to desferrioxamine (DFO), which has been shown clinically to possess antineoplastic activity. In this study, DFT was assessed for antineoplastic potential in hepatocellular carcinoma cell lines (HCC). This was done as there are few treatments for this aggressive neoplasm. The effects of DFT on cell proliferation, cell cycle progression, Fe uptake and toxicity were examined. To establish whether DFT was selective for cancer cells a comparison was made with normal (non‐proliferating) hepatocytes and non‐tumorigenic (proliferating) fibroblasts (SWISS‐3T3). DFT was a potent inhibitor of HCC proliferation (IC50∼40 μM). DFO also inhibited HCC proliferation under the same conditions, but was much less active (IC50=110 – 210 μM). When saturated with Fe, the activity of DFT, like DFO, was greatly diminished, suggesting it may act by depriving the cells of Fe or inactivating essential Fe pool(s). Indeed DFT rapidly decreased Fe uptake from Tf‐59Fe by hepatoma cells and also by normal hepatocytes. However, DFT (and DFO) had much less effect on cell survival in hepatocytes and fibroblasts than in hepatoma cells. DFT may, like DFO, inhibit the cell cycle in the S phase of DNA synthesis. Both chelators showed low toxicity. These results indicate that DFT has potent antineoplastic activity in HCC. Further investigation into the DFT class of Fe chelators seems warranted, particularly in view of its high activity in relation to DFO, a chelator which is already in clinical trial for neuroblastoma.British Journal of Pharmacology (2002) 135, 1393–1402; doi:10.1038/sj.bjp.0704507
Independent contribution of catecholamines to arrhythmogenesis during evolving infarction in the isolated rat heart
Authors: Clements‐Jewery Hugh , Hearse David J , Curtis Michael J 
Published: January 2005

Ventricular fibrillation (VF) in conscious rats with coronary artery ligation occurs in two phases, before (phase 1) and after (phase 2) 90 min of ischaemia respectively. The mechanisms of phase 2 VF are not established. Interestingly, phase 2 VF is absent in isolated (denervated) buffer‐perfused rat hearts. We investigated whether catecholamine supplementation (to mimic sympathetic drive) was sufficient to restore phase 2 VF in such hearts.
Isolated rat hearts (n=10 per group) underwent coronary ligation for 240 min. At 90 min, during a period of relative electrical stability, the perfusion solution was switched from standard (Krebs) to identical solution or Krebs containing catecholamines (313 nM noradrenaline and 75 nM adrenaline) with or without 10 μM trimazosin (an α1‐adrenoceptor antagonist) or 10 μM atenolol (a β1‐adrenoceptor antagonist).
Although in all groups the incidence of phase 1 VF was high (80 – 100%), the temporal distribution of VF was monophasic, i.e. only one heart in one group developed phase 2 VF (P=NS). Other ventricular arrhythmias (e.g., tachycardia; VT) exhibited a similar temporal distribution. Nevertheless, haemodynamic changes confirmed sympathomimetic effects of catecholamines, e.g., heart rate was increased from 278±7 beats min−1 in controls to 335±8 beats min−1 (P<0.05) by catecholamines, an effect that could be blocked by atenolol (285±7 beats min−1) but not by trimazosin (342±12 beats min−1). Coronary flow was correspondingly increased from 7.7±0.7 ml min−1 g−1 to 16.5±1.3 ml min−1 g−1 (P<0.05); this effect could be blocked by atenolol (8.1±0.6 ml min−1 g−1) and was enhanced by trimazosin (20.7±2.4 ml min−1 g−1).
In conclusion, despite evidence of adequate α‐ and β‐adrenoceptor activation, catecholamine supplementation to isolated buffer‐perfused rat hearts was insufficient to restore phase 2 VF. It therefore appears unlikely that catecholamines alone mediate phase 2 VF.

British Journal of Pharmacology (2002) 135, 807–815; doi:10.1038/sj.bjp.0704509
Differential effect of FR122047, a selective cyclo‐oxygenase‐1 inhibitor, in rat chronic models of arthritis
Authors: Ochi Takehiro , Goto Toshio 
Published: January 2005

We investigated the effects of FR122047 (1‐[(4,5‐bis(4‐methoxyphenyl)‐2‐thiazoyl)carbonyl]‐4‐methylpiperazine hydrochloride), a selective cyclo‐oxygenase (COX)‐1 inhibitor, in rat type II collagen‐induced arthritis (CIA) and adjuvant‐induced arthritis (AIA).
Using an ex vivo rat whole blood assay, FR122047 (0.032 – 3.2 mg kg−1) inhibited COX‐1‐derived thromboxane (TX) B2 production with ED50 value of 0.059 mg kg−1, indicating that it was orally active, but did not inhibit lipopolysaccharide‐induced prostaglandin (PG) E2 production derived by COX‐2.
Oral administration of FR122047 showed a dose‐dependent anti‐inflammatory effect in rat CIA with ED50 value of 0.56 mg kg−1. This drug also dose dependently suppressed the levels of PGE2 and TXB2 in CIA rat paws with ED50 values of 0.24 and 0.13 mg kg−1, respectively.
FR122047 had no effect in rat AIA model. In contrast, indomethacin, a non‐selective COX inhibitor, was anti‐inflammatory and reduced the formation of PGs in AIA rat paws.
Unlike indomethacin, chronic treatment of FR122047 did not damage the stomach mucosa in CIA rats.
These results demonstrate that COX‐1 contributes to the oedema and the formation of PGE2 and TXB2 in rat CIA model, but not in rat AIA model.
We conclude that FR122047 has an orally active and anti‐inflammatory effect mediated by inhibition of PGE2 and TXB2 produced by COX‐1 at a site of inflammation induced by type II collagen and it may be a useful tool for studying the involvement of COX‐1 in various in vivo models of inflammation.

British Journal of Pharmacology (2002) 135, 782–788; doi:10.1038/sj.bjp.0704511
Pirlindole and dehydropirlindole protect rat cultured neuronal cells against oxidative stress‐induced cell death through a mechanism unrelated to MAO‐A inhibition
Authors: Boland A , Gérardy J , Mossay D , Delapierre D , Seutin V 
Published: January 2005

It has been shown that the MAO (monoamine oxidase)‐B inhibitor deprenyl (DPR, selegiline) protects some cell types against oxidative stress. By decreasing H2O2 production, MAO‐A inhibitors could also reduce oxidative stress.
This study reports the effect of the MAO‐A inhibitors, pirlindole (PIR), dehydropirlindole (DHP), brofaromine (BRO) and moclobemide (MCL) on primary‐cultured brain cells exposed to iron‐mediated toxicity. A comparison with trolox (TRO), a hydrosoluble vitamin‐E analogue that protects against such an induced stress, was performed.
Rat hippocampal or cortical cultured cells were exposed either to 2 μM FeSO4 alone or in the presence of PIR, DHP, BRO, DPR, MCL or TRO. Cell survival (lactate‐dehydrogenase measurements, 16 h incubation), intracellular peroxide production (DCF‐fluorescence, 1 h incubation), lipoperoxidation (TBARS‐fluorescence, 6 h incubation) and mitochondrial function (MTT‐test, 16 h incubation) were assessed.
PIR, DHP and TRO significantly protected cultures (P<0.05) against Fe2+‐induced toxicity in a concentration‐dependent manner. The EC50s of these compounds were 6, 12 and 19 μM, respectively, in hippocampal cells. For cortical cell cultures incubated in the presence of iron and PIR or DHP, EC50s were 5 and 6 μM respectively. All Hill coefficients were close to unity. BRO, MCL and DPR were not protective in any type of culture. The IC50s for the inhibition of MAO‐A were 2, 2 and 0.2 μM for PIR, DHP and BRO, respectively. PIR, DHP and TRO, but not DPR, induced a significant decrease in both intracellular peroxide production and lipoperoxidation. They also improved mitochondrial function.
These experiments show that PIR and DHP can protect hippocampal and cortical neurons against oxidative stress at pharmacologically relevant concentrations. This protective effect seems unrelated to inhibition of MAO‐A, but possibly involves free radical scavenging.

British Journal of Pharmacology (2002) 135, 713–720; doi:10.1038/sj.bjp.0704519
Testosterone‐induced vasorelaxation in the rat mesenteric arterial bed is mediated predominantly via potassium channels
Authors: Tep‐areenan Patcharin , Kendall David A , Randall Michael D 
Published: January 2005

We have investigated the involvement of nitric oxide and K+ channels in the vasorelaxant responses to physiologically‐relevant concentrations of testosterone in the rat isolated mesenteric arterial bed.
Testosterone (100 pM – 10 μM) elicited concentration‐dependent relaxations in the isolated mesenteric arterial bed (pEC50=9.47 (9.22 – 9.73, 95% CI), maximal relaxation, Rmax=62.8±2.0%, n=6). A nitric oxide synthase (NOS) inhibitor, NG‐nitro‐L‐arginine methyl ester (L‐NAME, 300 μM) or removal of the endothelium significantly inhibited maximal relaxations to testosterone (L‐NAME: Rmax=51.4±1.1%, P<0.01, n=6; endothelium‐denuded: Rmax=46.9±2.8%, P<0.001, n=5).
Raising the extracellular K+ concentration to 30 and 60 mM, or pre‐treatment with 300 μM tetrabutylammonium chloride (TBA), a calcium‐activated K+ channel inhibitor, abolished vasorelaxations induced by testosterone. A selective inhibitor of ATP‐sensitive K+ (KATP) channels, glibenclamide (10 μM) and an inhibitor of voltage‐sensitive K+ (KV) channels, 4‐aminopyridine (4‐AP, 1 mM) did not affect testosterone‐induced responses. Vasorelaxation to 1 μM testosterone was significantly (P<0.05) inhibited by 100 nM charybdotoxin (ChTx), an inhibitor of large conductance calcium‐activated K+ (BKCa) channels (control: 63.3±9.9%, n=6; ChTx: 11.9±12.7%, n=3).
Neither the testosterone receptor antagonist, flutamide (10 μM) nor an aromatase inhibitor, aminoglutethimide (10 μM) inhibited testosterone‐induced responses.
In conclusion, the present findings demonstrate, in the rat isolated mesenteric arterial bed, that testosterone causes acute vasorelaxations at physiologically relevant concentrations which are, in part, mediated via NO‐ and endothelium‐dependent pathways. However, the activation of BKCa channels plays a substantial role in testosterone‐induced vasorelaxation.

British Journal of Pharmacology (2002) 135, 735–740; doi:10.1038/sj.bjp.0704522
Comparison of the ORL1 receptor‐mediated inhibition of noradrenaline release in human and rat neocortical slices
Authors: Rominger Axel , Förster Stefan , Zentner Josef , Dooley David J , McKnight Alexander T , Feuerstein Thomas J , Jackisch Rolf , Vlaskovska Mila 
Published: January 2005

The effects of nociceptin/orphanin (N/OFQ) and the selective ORL1 antagonist J‐113397 (1‐[(3R,4R)‐1‐cyclo‐octylmethyl‐3‐hydroxymethyl‐4‐piperidyl]‐3‐ethyl‐1,3‐dihydro‐2H‐benzimidazol‐2‐one) were studied on electrically‐evoked release of [3H]‐noradrenaline ([3H]‐NA) from human and rat neocortical slices. Specimens of human tissue were obtained during neurosurgery.
Slices were preincubated with 0.1 μM[3H]‐NA, superfused in the presence of desipramine, idazoxan, and naloxone (1 μM each), and stimulated electrically up to three times under conditions (4 pulses, 100 Hz, 2 ms, 60 mA) that prevent inhibition of evoked [3H]‐NA release by endogenous modulators accumulating during ongoing stimulation.
N/OFQ decreased electrically‐evoked [3H]‐NA release in both human and rat neocortical slices in a concentration‐dependent manner. The respective pEC50 values were 7.74 [CI95: 7.47, 8.04] and 7.64 [CI95: 7.48, 7.77], and the maximal inhibitions were 36.9%[CI95: 32.4%, 41.8%] and 66.4%[CI95: 61.7%, 72.7%].
N/OFQ (1 μM) inhibited K+ (15 mM)‐evoked [3H]‐NA release from neocortical slices of both species by a similar magnitude, either in the presence or absence of tetrodotoxin.
The nonpeptide ORL1 antagonist J‐113397 competitively attenuated, with similar potency, the inhibition of electrically‐evoked [3H]‐NA release by N/OFQ in both species (pA2 values: human, 8.16 [CI95: 7.64, 8.64]; rat, 8.47 [CI95: 8.27, 8.67]). J‐113397 (0.1 μM) by itself did not alter either the evoked or spontaneous [3H]‐NA release, suggesting that presynaptic ORL1 receptors are not activated by endogenous N/OFQ under the stimulation conditions employed.
This study provides the first evidence that N/OFQ modulates [3H]‐NA release in human neocortex via specific ORL1 receptors most likely located on noradrenergic axon terminals.

British Journal of Pharmacology (2002) 135, 800–806; doi:10.1038/sj.bjp.0704523
Inhibition of slow Ca2+‐activated K+ current by 4‐aminopyridine in rat hippocampal CA1 pyramidal neurones
Authors: Andreasen Mogens 
Published: January 2005

The effect of 4‐aminopyridine (4‐AP) on the slow afterhyperpolarization (sAHP) seen after high frequency dendritic or somatic firing was investigated in rat hippocampal CA1 pyramidal neurones (PC). Intracellular recordings were obtained from the distal apical dendrites and somata and suprathreshold depolarizing current pulses were used to evoke a sAHP. The sAHP was blocked by low concentrations of carbacholine (Cch) but insensitive to high concentrations of apamin.
In the presence of extracellular 4‐AP, the first dendritic sAHP evoked was reduced compared to a maximal sAHP evoked in the absence of 4‐AP. The reduction was evident at submillimolar concentration and increased to about 80% with 4 mM 4‐AP.
The stability of the 4‐AP‐induced block was affected by the type of anion used in the electrode solution. With K+ acetate (KAc) or K+ methylsulphate (KMeSO4) containing electrodes, the block was progressively removed during the initial 300 – 400 s of recordings. With KCl containing electrodes, the block remained stable and was 10% larger than that obtained with acetate. Detailed investigations showed that intracellular acetate promotes the removal of the 4‐AP‐induced block in an activity‐dependent manner.
Intracellularly applied 4‐AP also induced an acetate‐sensitive block of the dendritic sAHP.
4‐AP also blocked the somatic sAHP and the stability of the block showed the same sensitivity towards anions as the dendritic sAHP.
Thus 4‐AP appears to block the slow Ca2+‐activated K+ current underlying the sAHP in a complex manner which is sensitive to certain types of anions.

British Journal of Pharmacology (2002) 135, 1013–1025; doi:10.1038/sj.bjp.0704533
Orphanin FQ inhibits capsaicin‐induced thermal nociception in monkeys by activation of peripheral ORL1 receptors
Authors: Ko M C H , Naughton N N , Traynor J R , Song M S , Woods J H , Rice K C , McKnight A T 
Published: January 2005

Orphanin FQ (OFQ), an endogenous peptide for ORL1 receptors, has been identified. Although the actions of OFQ have much in common with those of opioid peptides at the cellular level, behavioral studies in rodents seem conflicting.
The aim of this study was to investigate the potential pronociceptive or antinociceptive function of peripheral ORL1 receptors in primates. Experiments were conducted to verify whether local administration of OFQ can attenuate capsaicin‐induced nociception and whether peripheral ORL1 receptors selectively mediate the local action of OFQ in monkeys.
Capsaicin (100 μg) was administered subcutaneously in the tail to locally evoke a nociceptive response (thermal allodynia/hyperalgesia), which was manifested as a reduced tail‐withdrawal latency in normally innocuous 46°C warm water.
Co‐administration of OFQ (1 – 30 μg) with capsaicin in the tail dose‐dependently inhibited thermal nociception. However, a locally effective dose of OFQ (30 μg), when applied in the back, did not inhibit capsaicin‐induced nociception.
OFQ‐induced local antinociception was antagonized by a small dose (10 μg) of J‐113397, a selective ORL1 receptor antagonist, in the tail. Similarly, s.c. administration of 10 μg of J‐113397 in the back did not antagonize local antinociception of OFQ.
In addition, s.c. administration of either OFQ or J‐113397 in the tail alone did not change its thermal nociceptive threshold. Local administration of opioid receptor antagonists selective for mu, kappa, and delta opioid receptors did not antagonize OFQ‐induced local antinociception. Local administration of J‐113397 also did not interfere with the local actions of mu, kappa, and delta opioid agonists in the tail.
These results provide the first functional evidence that activation of peripheral ORL1 receptors produces thermal antinociception in primates and this action is independent of antinociception produced at classical opioid receptors.

British Journal of Pharmacology (2002) 135, 943–950; doi:10.1038/sj.bjp.0704535
Inhibition of the NMDA response by pregnenolone sulphate reveals subtype selective modulation of NMDA receptors by sulphated steroids
Authors: Malayev Andrew , Gibbs Terrell T , Farb David H 
Published: January 2005

The neurosteroid pregnenolone sulphate (PS) potentiates N‐methyl‐D‐aspartate (NMDA) receptor mediated responses in various neuronal preparations. The NR1 subunit can combine with NR2A, NR2B, NR2C, or NR2D subunits to form functional receptors. Differential NR2 subunit expression in brain and during development raises the question of how the NR2 subunit influences NMDA receptor modulation by neuroactive steroids.
We examined the effects of PS on the four diheteromeric NMDA receptor subtypes generated by co‐expressing the NR1100 subunit with each of the four NR2 subunits in Xenopus oocytes. Whereas PS potentiated NMDA‐, glutamate‐, and glycine‐induced currents of NR1/NR2A and NR1/NR2B receptors, it was inhibitory at NR1/NR2C and NR1/NR2D receptors.
In contrast, pregnanolone sulphate (3α5βS), a negative modulator of the NMDA receptor that acts at a distinct site from PS, inhibited all four subtypes, but was approximately 4 fold more potent at NR1/NR2C and NR1/NR2D than at NR1/NR2A and NR1/NR2B receptors.
These findings demonstrate that residues on the NR2 subunit are key determinants of modulation by PS and 3α5βS. The modulatory effects of PS, but not 3α5βS, on dose‐response curves for NMDA, glutamate, and glycine are consistent with a two‐state model in which PS either stabilizes or destabilizes the active state of the receptor, depending upon which NR2 subunit is present.
The selectivity of sulphated steroid modulators for NMDA receptors of specific subunit composition is consistent with a neuromodulatory role for endogenous sulphated steroids. The results indicate that it may be possible to develop therapeutic agents that target steroid modulatory sites of specific NMDA receptor subtypes.

British Journal of Pharmacology (2002) 135, 901–909; doi:10.1038/sj.bjp.0704543
Constitutive activation of the neurotensin receptor 1 by mutation of Phe358 in Helix seven
Authors: Barroso Séverine , Richard Françoise , Nicolas‐Ethève Delphine , Kitabgi Patrick , Labbé‐Jullié Catherine 
Published: January 2005

The neurotensin receptor 1, NTS1, is a G protein‐coupled receptor with seven transmembrane domains (TM) that mediates most of the known effects of the neuropeptide. Our previous studies have pointed to extracellular loop 3 and adjacent TM7 as being potentially involved in agonist‐induced activation of the NTS1.
Here we investigated residues in these domains that might be involved in transconformational activation of the rat NTS1. Single amino acid mutated receptors were expressed in COS cells and inositol phosphate (IP) and cyclic AMP productions were studied.
The F358A mutation in TM7 resulted in a time‐ and receptor concentration‐dependent increase in spontaneous IP production. At expression levels of 12 pmol mg−1, agonist‐independent IP production was increased 10 fold over basal for the F358A mutant receptor whereas the wild type NTS1 exhibited virtually no spontaneous activity at expression levels of 7.5 pmol mg−1.
Neurotensin remained agonist on the F358A mutant receptor with a maximal effect that amounted to greater than twice basal IP levels. SR 48692 was inverse agonist at the mutant receptor, reversing IP production almost back to the levels measured in wild type NTS1‐transfected cells.
Cyclic AMP production was not constitutively activated with the F358A mutant receptor but was stimulated by neurotensin with the same concentration dependence as that observed with the wild type NTS1.
This is the first report, to our knowledge, of a constitutively active mutant of the NTS1. The data are consistent with TM7 being involved in the transconformational changes that lead to agonist‐induced coupling of the NTS1 to Gq.

British Journal of Pharmacology (2002) 135, 997–1002; doi:10.1038/sj.bjp.0704546
Characterization of an apamin‐sensitive small‐conductance Ca2+‐activated K+ channel in porcine coronary artery endothelium: relevance to EDHF
Authors: Burnham M P , Bychkov R , Félétou M , Richards G R , Vanhoutte P M , Weston A H , Edwards G 
Published: January 2005

The apamin‐sensitive small‐conductance Ca2+‐activated K+ channel (SKCa) was characterized in porcine coronary arteries.
In intact arteries, 100 nM substance P and 600 μM 1‐ethyl‐2‐benzimidazolinone (1‐EBIO) produced endothelial cell hyperpolarizations (27.8±0.8 mV and 24.1±1.0 mV, respectively). Charybdotoxin (100 nM) abolished the 1‐EBIO response but substance P continued to induce a hyperpolarization (25.8±0.3 mV).
In freshly‐isolated endothelial cells, outside‐out patch recordings revealed a unitary K+ conductance of 6.8±0.04 pS. The open‐probability was increased by Ca2+ and reduced by apamin (100 nM). Substance P activated an outward current under whole‐cell perforated‐patch conditions and a component of this current (38%) was inhibited by apamin. A second conductance of 2.7±0.03 pS inhibited by d‐tubocurarine was observed infrequently.
Messenger RNA encoding the SK2 and SK3, but not the SK1, subunits of SKCa was detected by RT – PCR in samples of endothelium. Western blotting indicated that SK3 protein was abundant in samples of endothelium compared to whole arteries. SK2 protein was present in whole artery nuclear fractions.
Immunofluorescent labelling confirmed that SK3 was highly expressed at the plasmalemma of endothelial cells and was not expressed in smooth muscle. SK2 was restricted to the peri‐nuclear regions of both endothelial and smooth muscle cells.
In conclusion, the porcine coronary artery endothelium expresses an apamin‐sensitive SKCa containing the SK3 subunit. These channels are likely to confer all or part of the apamin‐sensitive component of the endothelium‐derived hyperpolarizing factor (EDHF) response.

British Journal of Pharmacology (2002) 135, 1133–1143; doi:10.1038/sj.bjp.0704551