bluuebunny/crossref_metadata_2025_split huggingface dataset:
No evidence for a significant non‐nitrergic, hyperpolarising factor contribution to field stimulation‐induced relaxation of the mouse anococcygeus
Authors: Fonseca Mario , Uddin Nazim , Gibson Alan 
Published: January 2005

The aim of the study was to determine whether a nerve‐derived hyperpolarizing factor (NDHF) might contribute to non‐adrenergic, non‐cholinergic (NANC) relaxations of the mouse anococcygeus when low concentrations of contractile agent are used to raise tone and low frequencies of field stimulation applied; such a non‐nitrergic NDHF has been proposed to contribute to NANC relaxations of the rat anococcygeus and guinea‐pig taenia coli.
Phenylephrine (0.1–100 μM) produced concentration‐related contractions of the mouse isolated anococcygeus muscle; 0.2 μM phenylephrine (EC26) was used to raise tone in subsequent experiments.
Field stimulation (0.5, 1.0 and 5.0 Hz) produced frequency‐dependent relaxations of phenylephrine‐induced tone. In the presence of the nitric oxide synthase inhibitor L‐NG‐nitro‐arginine (L‐NOARG; 100 μM), the soluble guanylate cyclase inhibitor 1H‐[1,2,4]oxodiazolo[4,3‐a]quinoxalin‐1‐one (ODQ; 5 μM), or a combination of these two drugs, relaxations to field stimulation were abolished at all frequencies studied. Relaxations to sodium nitroprusside (0.01–5 μM) were unaffected by L‐NOARG but strongly inhibited by ODQ; neither enzyme inhibitor affected relaxations to 8‐Br‐cyclic GMP (10 μM).
Nifedipine (1 μM) reduced the contractile response to 0.2 μM phenylephrine by 38%; however, it had no effect on NANC relaxations.
It is concluded that NANC relaxations of the mouse anococcygeus are purely nitrergic and that there is no significant contribution from a putative NDHF.
Effect of inhibitors of Na+/H+‐exchange and gastric H+/K+ ATPase on cell volume, intracellular pH and migration of human polymorphonuclear leucocytes
Authors: Ritter M , Schratzberger P , Rossmann H , Wöll E , Seiler K , Seidler U , Reinisch N , Kähler C M , Zwierzina H , Lang H J , Lang F , Paulmichl M , Wiedermann C J 
Published: January 2005

Stimulation of chemotaxis of human polymorphonuclear leucocytes (PMNs) with the chemoattractive peptide fMLP (N‐formyl‐Met‐Leu‐Phe) is paralleled by profound morphological and metabolic alterations like changes of intracellular pH (pHi) and cell shape. The present study was performed to investigate the interrelation of cell volume (CV) regulatory ion transport, pHi and migration of fMLP stimulated PMNs.
Addition of fMLP to PMNs stimulated directed migration in Boyden chamber assays and was accompanied by rapid initial intracellular acidification and cell swelling.
Inhibition of the Na+/H+ exchanger suppressed fMLP stimulated cell migration, accelerated the intracellular acidification and inhibited the fMLP‐induced cell swelling.
Step omission of extracellular Na+ caused intracellular acidification, which was accelerated by subsequent addition of gastric H+/K+ ATPase inhibitor SCH 28080, or by omission of extracellular K+ ions. In addition Na+ removal caused cell swelling, which was further enhanced by fMLP.
H+/K+ATPase inhibitors omeprazole and SCH 28080 inhibited stimulated migration and blunted the fMLP‐induced increase in CV.
Increasing extracellular osmolarity by addition of mannitol to the extracellular solution caused cell shrinkage followed by regulatory volume increase, partially due to activation of the Na+/H+ exchanger. In fMLP‐stimulated cells the CV increase was counteracted by simultaneous addition of mannitol. Under these conditions the fMLP stimulated migration was inhibited.
The antibacterial activity of PMNs was not modified by Hoe 694 or omeprazole.
Western analysis with a monoclonal anti gastric H+/K+ATPase β‐subunit antibody detected a glycosylated 35 kD core protein in lysates of mouse and human gastric mucosa as well as in human PMNs.
The results indicate that fMLP leads to cell swelling of PMNs due to activation of the Na+/H+ exchanger and a K+‐dependent H+‐extruding mechanism, presumably an H+/K+ ATPase. Inhibition of these ion transporters suppresses the increase in CV and precludes PMNs from stimulated migration.
Species differences in the distribution of β‐adrenoceptor subtypes in bladder smooth muscle
Authors: Yamazaki Yoshinobu , Takeda Hiroo , Akahane Masuo , Igawa Yasuhiko , Nishizawa Osamu , Ajisawa Yukiyoshi 
Published: January 2005

The β‐adrenoceptor (β‐AR) subtypes mediating relaxation of the rabbit, rat and canine detrusors were subjected to functional investigation using selective β‐AR agonists and antagonists.
In all three species, isoprenaline, noradrenaline and adrenaline each produced a concentration‐dependent relaxation of the detrusor. The rank order for their relaxing potency was isoprenaline> adrenaline>noradrenaline in rabbits and rats, but isoprenaline>noradrenaline>adrenaline in dogs.
Dobutamine did not produce relaxation of the detrusors at concentrations that are selective for β1‐AR. The selective β2‐AR agonist, procaterol, had a more potent relaxing effect on rabbit and rat detrusors than on the canine detrusor. CGP‐12177A, a selective β3‐AR agonist, was more effective in the rabbit than in the other two species. On the other hand, the relaxing effect of another β3‐AR agonist, CL316243, was more pronounced in dogs and rats than in rabbits.
CGP‐20712A (10−9 to 10−7 M), a selective β1‐AR antagonist, caused a slight rightward shift of the concentration‐relaxation response curve for isoprenaline in the canine detrusor (pA2 9.41), but not in the rabbit and rat detrusors. ICI‐118,551, a selective β2‐AR antagonist, antagonized the isoprenaline‐induced relaxation in rabbits (pA2 9.45) and rats (pA2 9.05), but not in dogs. Bupranolol, a non‐selective β‐AR antagonist, caused a rightward shift of the concentration‐relaxation curve for isoprenaline in the rabbit (pA2 9.32) and rat (pA2 8.98). However, higher concentrations (3×10−8 to 10−5 M) were needed to induce a rightward shift of the curve for isoprenaline in the dog (pA2 8.19) than in the other two species.
We have confirmed that the distribution of β‐AR subtypes in the detrusor muscle varies significantly from species to species and we provide here the first evidence of the presence of β3‐AR in the detrusor. It is suggested that the relaxation induced by adrenoceptor agonists in urinary bladder smooth muscle may be mediated mainly via β2‐AR in rabbits, via both β2‐ and β3‐AR in rats, but mainly via β3‐AR in dogs.
Synergistic effects of caspase inhibitors and MK‐801 in brain injury after transient focal cerebral ischaemia in mice
Authors: Ma Jianya , Endres Matthias , Moskowitz Michael A 
Published: January 2005

Excitotoxic and apoptotic mechanisms have been implicated in the pathophysiology of cerebral ischaemia. Both MK‐801, an NMDA receptor antagonist, or peptide inhibitors of the caspase family (z‐VAD.FMK and z‐DEVD.FMK), protect mouse brain from ischaemic cell damage. In this study, we examined whether these drugs which act via distinct mechanisms, afford even greater neuroprotection when given in combination following 2 h MCA occlusion (filament model) and 18 h reperfusion.
Given alone as pretreatment, MK‐801 (1, 3 and 5 mg kg−1, but not 0.3 mg kg−1, i.p.) decreased infarct size by 34–75%. When injected 1 h after occlusion and before reperfusion, 3 mg kg−1 reduced injury but not when administered 1 h after reperfusion.
Pretreatment with a subthreshold dose of MK‐801 (0.3 mg kg−1) plus a subthreshold dose of z‐VAD.FMK (27 ng) or z‐DEVD (80 ng) significantly decreased infarct size by 29 and 30%, respectively, and enhanced neurological function.
Administering a subthreshold dose of z‐VAD.FMK (27 ng) or z‐DEVD.FMK (80 ng) as pretreatment extended the time window for MK‐801 (3 mg kg−1) by 2 h from 1 h before reperfusion to at least 1 h after reperfusion.
Pretreating with a subthreshold dose of MK‐801 (0.3 mg kg−1) extended the time window for z‐DEVD.FMK (480 ng) from 1 h after reperfusion to at least 3 h after reperfusion.
We conclude that caspase inhibitors which putatively block apoptotic cell death and inhibit cytokine production and the NMDA antagonist MK‐801 act synergistically and prolong their respective therapeutic windows in cerebral ischaemia.
KATP‐channel activation: effects on myocardial recovery from ischaemia and role in the cardioprotective response to adenosine A1‐receptor stimulation
Authors: Ford William R , Lopaschuk Gary D , Schulz Richard , Clanachan Alexander S 
Published: January 2005

Optimization of myocardial energy substrate metabolism improves the recovery of mechanical function of the post‐ischaemic heart. This study investigated the role of KATP‐channels in the regulation of the metabolic and mechanical function of the aerobic and post‐ischaemic heart by measuring the effects of the selective KATP‐channel activator, cromakalim, and the effects of the KATP‐channel antagonist, glibenclamide, in rat fatty acid perfused, working hearts in vitro. The role of KATP channels in the cardioprotective actions of the adenosine A1‐receptor agonist, N6‐cyclohexyladenosine (CHA) was also investigated.
Myocardial glucose metabolism, mechanical function and efficiency were measured simultaneously in hearts perfused with modified Krebs‐Henseleit solution containing 2.5 mM Ca2+, 11 mM glucose, 1.2 mM palmitate and 100 mu l−1 insulin, and paced at 300 beats min−1. Rates of glycolysis and glucose oxidation were measured from the quantitative production of 3H2O and 14CO2, respectively, from [5‐3H/U‐14C]‐glucose.
In hearts perfused under aerobic conditions, cromakalim (10 μM), CHA (0.5 μM) or glibenclamide (30 μM) had no effect on mechanical function. Cromakalim did not affect glycolysis or glucose oxidation, whereas glibenclamide significantly increased rates of glycolysis and proton production. CHA significantly reduced rates of glycolysis and proton production but had no effect on glucose oxidation. Glibenclamide did not alter CHA‐induced inhibition of glycolysis and proton production.
In hearts reperfused for 30 min following 30 min of ischaemia, left ventricular minute work (LV work) recovered to 24% of aerobic baseline values. Cromakalim (10 μM), administered 5 min before ischaemia, had no significant effect on mechanical recovery or glucose metabolism. CHA (0.5 μM) significantly increased the recovery of LV work to 67% of aerobic baseline values and also significantly inhibited rates of glycolysis and proton production. Glibenclamide (30 μM) significantly depressed the recovery of mechanical function to <1% of aerobic baseline values and stimulated glycolysis and proton production.
Despite the deleterious actions of glibenclamide per se in post‐ischaemic hearts, the beneficial effects of CHA (0.5 μM) on the recovery of mechanical function and proton production were not affected by glibenclamide.
The data indicate that the cardioprotective mechanism of adenosine A1‐receptor stimulation does not involve the activation of KATP‐channels. Furthermore, in rat fatty acid perfused, working hearts, stimulation of KATP‐channels is not cardioprotective and has no significant effects on myocardial glucose metabolism.
Bronchodilatationin vivoby carbon monoxide, a cyclic GMP related messenger
Authors: Cardell Lars‐Olaf , Ueki Iris F. , Stjärne Pär , Agusti Carlos , Takeyama Kiyoshi , Lindén Anders , Nadel Jay A. 
Published: January 2005

Recent studies suggest that gaseous carbon monoxide (CO) is involved in neurotransmission and that this molecule also is an important vasodilatorin vivo. In the present study we evaluated the effect of inhaled CO on guinea‐pig airway smooth muscle tone. The mechanisms involved were characterized by use of a cyclic GMP antagonist, Rp‐8Br‐cyclic GMPS, and a nitric oxide synthase inhibitor,l‐NAME.Anaesthetized, ventilated guinea‐pigs were given a bolus injection of histamine (0.12 mg kg−1, i.v.), followed by a continuous infusion of histamine (0.30 μg kg−1min−1) to increase total pulmonary resistance (RL). Subsequent exposure to 7, 15 or 30 breaths of CO (100%), resulted in a dose‐dependent inhibition of the bronchoconstriction. In the highest dose tested (30 breaths), CO inhibited 80% of the histamine‐induced increase inRL.In separate experiments, animals receiving histamine infusions followed by 30 breaths of CO, were pretreated with Rp‐8Br‐cyclic GMPS (0.05 mg kg−1). This pretreatment abolished >60% of the CO‐induced reduction inRL, but it had no effect on the bronchodilator response induced by salbutamol. In another set of experiments animals were pretreated withl‐NAME (1.60 mg kg−1). In contrast to the Rp‐8Br‐cyclic GMPS pretreatment, the pretreatment withl‐NAME did not affect the CO‐induced reduction inRL.The present findings indicate that CO causes bronchodilatationin vivovia cyclic GMP.British Journal of Pharmacology(1998)124, 1065–1068; doi:10.1038/sj.bjp.0701878
Neurogenic contraction and relaxation of human penile deep dorsal vein
Authors: Segarra Gloria , Medina Pascual , Domenech Cristina , Martínez León Juan B , Vila José M , Aldasoro Martin , Lluch Salvador 
Published: January 2005

The aim of the present study was to characterize neurogenic and pharmacological responses of human penile deep dorsal vein and to determine whether the responses are mediated by nitric oxide from neural or endothelial origin.
Ring segments of human penile deep dorsal vein were obtained from 22 multiorgan donors during procurement of organs for transplantation. The rings were suspended in organ bath chambers for isometric recording of tension. We then studied the contractile and relaxant responses to electrical field stimulation and to vasoactive agents.
Electrical field stimulation (0.5–2 Hz) and noradrenaline (3×10−10–3×10−5 M) caused frequency‐ and concentration‐dependent contractions that were of greater magnitude in veins denuded of endothelium. The inhibitor of nitric oxide synthesis NG‐nitro‐L‐arginine methyl ester hydrochloride (L‐NAME, 10−4 M) increased the adrenergic responses only in rings with endothelium.
In preparations contracted with noradrenaline in the presence of guanethidine (10−6 M) and atropine (10−6 M), electrical stimulation induced frequency‐dependent relaxations. This neurogenic relaxation was prevented by L‐NAME, methylene blue (3×10−5 M) and tetrodotoxin (10−6 M), but was unaffected by removal of endothelium.
Acetylcholine (10−8–3×10−5 M) and substance P (3×10−11–3×10−7 M) induced endothelium‐dependent relaxations. In contrast, sodium nitroprusside (10−9–3×10−5 M) and papaverine (10−8–3×10−5 M) caused endothelium‐independent relaxations.
The results provide functional evidence that the human penile deep dorsal vein is an active component of the penile vascular resistance through the release of nitric oxide from both neural and endothelial origin. Dysfunction in any of these sources of nitric oxide should be considered in some forms of impotence.
The effect of the nonpeptide neurotrophic compound SR 57746A on the progression of the disease state of the pmn mouse
Authors: Duong F , Fournier J , Keane P E , Guénet J L , Soubrié P , Warter J M , Borg J , Poindron P 
Published: January 2005

The progressive motor neuronopathy (pmn) mouse is an autosomal recessive mutant, in which the homozygotes suffer caudio‐cranial degeneration of motor axons and die several weeks after birth. This strain provides the opportunity of testing potential therapeutic strategies for the treatment of motor neurone diseases such as amyotrophic lateral sclerosis. We have performed a study of the effects on the pmn mouse of SR 57746A, an orally‐active, non‐peptide compound which has been found to exhibit neurotrophic effects in vitro and in vivo. In order to treat the affected mice from birth, the mothers were administered 2.5 mg kg−1, p.o., SR 57746A every two days until the weaning of the offspring (at day 20); then the offspring were given every two days a dose of 30 μg kg−1, p.o., until their death.
Affected mice treated with SR 57746A had a lifespan 50% longer than that of the vehicle‐treated mice (P=0.01). Compared to vehicle‐treated pmn mice, SR 57746A improved the performance of the pmn mice in three different behavioural tasks. SR 57746A also maintained the amplitude of the motor evoked response of the gastrocnemius muscle, reduced the distal motor latency, and delayed the occurrence of the spontaneous denervation activity in this muscle. Histological studies indicated that at 20 days of age the mean surface areas of the fibres of the sciatic nerve were higher in SR 57746A‐treated than in vehicle‐treated mice.
At present, SR 57746A is the only orally active, nonpeptide compound known to be capable of delaying the progression of the motor neurone degeneration in pmn mice.
Nucleotide‐evoked calcium signals and anion secretion in equine cultured epithelia that express apical P2Y2 receptors and pyrimidine nucleotide receptors
Authors: Wilson S M , Law V W Y , Pediani J D , Allen E A , Wilson G , Khan Z E , Ko W H 
Published: January 2005

Experiments with a spontaneously transformed equine epithelial cell line showed that certain nucleotides increased intracellular free calcium ([Ca2+]i) in cells plated on glass coverslips. The rank order of potency was ATP=UTP>5‐Br‐UTP, whilst UDP and ADP were ineffective. The response thus appears to be mediated by P2Y2 receptors.
Nucleotides also increased short circuit current (ISC) in cells grown into epithelial monolayers and the rank order of potency was UDP>UTP>5‐Br‐UTP>ATP>ADP. The increase in [Ca2+]i and the rise in ISC thus have different pharmacological properties. Cross‐desensitization experiments indicated that, as well as P2Y2 receptors, the monolayer cultures express at least one additional receptor population that allowed nucleotides to increase ISC.
The UDP‐evoked increase in ISC was essentially abolished in BAPTA‐loaded epithelia suggesting that this response is dependent upon increased [Ca2+]i. Moreover, experiments in which ISC and [Ca2+]i were measured simultaneously showed that the UDP‐ and ADP‐evoked increases in ISC were accompanied by increases in [Ca2+]i.
When grown under conditions which favour the development of a polarized phenotype, these epithelial cells thus appear to express [Ca2+]i‐mobilizing receptors sensitive to UDP and ADP that are not present in non‐polarized cells on coverslips.
Evidence that P2Y4 nucleotide receptors are involved in the regulation of rat aortic smooth muscle cells by UTP and ATP
Authors: Harper Simon , Webb Tania E , Charlton Steven J , Ng Leong L , Boarder Michael R 
Published: January 2005

Previous studies have shown that ATP and UTP are able to stimulate phospholipase C (PLC) and proliferation in cultured aortic smooth muscle cells. Here we set out to characterize the receptor responsible, and investigate a possible role for p42 and p44 mitogen activated protein kinase (MAPK) in the proliferative response.
The phospholipase C response of spontaneously hypertensive rat (SHR) derived aortic smooth muscle cells in culture showed that the response to ATP was partial compared to the response to UTP.
Further studies characterized the responses of the SHR derived cells. UTP was the only full agonist with the SHR cells; UDP gave a partial response while ADP, 2‐methythio‐ATP and α,β‐methylene ATP were essentially ineffective. The response to UDP was almost lost in the presence of hexokinase, consistent with this being due to extracellular conversion to UTP. These observations are inconsistent with the response being mediated by either P2Y1 or P2Y6 receptors.
When increasing concentrations of ATP were present with a maximally effective concentration of UTP, the size of the response diminished, consistent with UTP and ATP acting at a single population of receptors for which ATP was a partial agonist. This is inconsistent with a response mainly at P2Y2 receptors.
1321N1 cells transfected with human P2Y4 receptors gave a similar agonist response profile, with ATP being partial compared to UTP, loss of response to UDP with hexokinase treatment, and with the response to UTP diminishing in the presence of increasing concentrations of ATP.
Use of the reverse transcriptase‐polymerase chain reaction confirmed the presence of mRNA encoding P2Y4 receptors in SHR derived vascular smooth muscle cells. Transcripts for P2Y2, P2Y4 and P2Y6 receptors, but not P2Y1 receptors, were detected.
Stimulation of SHR derived cells with UTP enhanced the tyrosine phosphorylation of both p42 and p44 MAPK, and the incorporation of [3H]‐thymidine into DNA. Both these responses were diminished in the presence of an inhibitor of activation of MAPK.
These results lead to the conclusion that in SHR derived cultured aortic smooth muscle cells, PLC responses to extracellular UTP and ATP are predominantly at P2Y4 receptors, and suggest that these receptors are coupled to mitogenesis via p42/p44 MAPK.
Pharmacological characterization of thromboxane and prostanoid receptors in human isolated urinary bladder
Authors: Palea S , Toson G , Pietra C , Trist D G. , Artibani W , Romano O , Corsi M 
Published: January 2005

Cumulative concentration‐response curves (CRC) to prostaglandin E1 (PGE1), PGE2, PGD2 and PGF2α (0.01–30 μM) and to the thromboxane A2 (TXA2) receptor agonist U‐46619 (0.01–30 μM) were constructed in human isolated detrusor muscle strips both in basal conditions and during electrical field stimulation.
All the agonists tested contracted the detrusor muscle. The rank order of agonist potency was: PGF2α>U‐46619>PGE2 whereas weak contractile responses were obtained with PGD2 and PGE1. Any of the agonists tested was able to induce a clear plateau of response even at 30 μM.
The selective TXA2 antagonist, GR 32191B (vapiprost), antagonized U‐46619‐induced contractions with an apparent pKB value of 8.27±0.12 (n=4 for each antagonist concentration). GR 32191B (0.3 μM) did not antagonize the contractile responses to PGF2α and it was a non‐surmountable antagonist of PGE2 (apparent pKB of 7.09±0.04; n=5). The EP receptor antagonist AH 6809 at 10 μM shifted to the right the CRC to U‐46619 (apparent pKB value of 5.88±0.04; n=4).
Electrical field stimulation (20 Hz, 70 V, pulse width 0.1 ms, trains of 5 s every 60 s) elicited contractions fully sensitive to TTX (0.3 μM) and atropine (1 μM). U‐46619 (0.01–3 μM) potentiated the twitch contraction in a dose‐dependent manner and this effect was competitively antagonized by GR 32191B with an estimated pKB of 8.54±0.14 (n=4 for each antagonist concentration). PGF2α in the range 0.01–10 μM (n=7), but not PGE2 and PGE1 (n=3 for each), also potentiated the twitch contraction of detrusor muscle strips (23.5±0.3% of KCl 100 mM‐induced contraction) but this potentiation was unaffected by 0.3 μM GR 32191B (n=5).
Cumulative additions of U‐46619 (0.01–30 μM) were without effect on contractions induced by direct smooth muscle excitation (20 Hz, 40 V, 6 ms pulse width, trains of 2 s every 60 s, in the presence of TTX 1 μM; n=3). Moreover, pretreatment of the tissue with 0.3 μM U‐46619 did not potentiate the smooth muscle response to 7 μM bethanecol (n=2).
We concluded that TXA2 can induce direct contraction of human isolated urinary bladder through the classical TXA2 receptor. Prostanoid receptors, fully activated by PGE2 and PGF2α are also present. All these receptors are probably located post‐junctionally. The rank order of agonist potency and the fact that GR32191B, but not AH6809, antagonized responses to PGE2 seem to indicate the presence of a new EP receptor subtype. Moreover, we suggest the presence of prejuctional TXA2 and FP receptors, potentiating acetylcholine release from cholinergic nerve terminals.