bluuebunny/crossref_metadata_2025_split huggingface dataset:
Possible roles of protein kinases in neutrophil chemotactic factor production by leucocytes in allergic inflammation in rats
Authors: Tanabe Jun‐Ichi , Watanabe Masako , Kondoh Sachiko , Mue Suetsugu , Ohuchi Kazuo 
Published: July 2012

In an air pouch‐type allergic inflammation model in rats, leucocytes that had infiltrated into the pouch fluid collected 4 h after the antigen challenge produced proteinaceous chemotactic factors for neutrophils when they were incubated in the medium.
To clarify the mechanism of activation of the infiltrated leucocytes in producing these factors, the effects of protein kinase inhibitors on neutrophil chemotactic factor production were examined.
When the infiltrated leucocytes were incubated for 4h in medium containing the non‐selective protein kinase inhibitor K‐252a (1–100 ng ml−1, 2.14–214 nm), the tyrosine kinase inhibitor genistein (1–50 μg ml−1, 3.7–185 μm), and the more selective protein kinase C inhibitor H‐7 (5–100 μg ml−1, 13.7–274 μm); neutrophil chemotactic activity in the conditioned medium was decreased in a concentration‐dependent manner, but the adenosine 3′:5′‐cyclic monophosphate (cAMP)‐dependent protein kinase inhibitor H‐89 (1–1000 ng ml−1, 2.24–2240 nm) showed no effect.
Isoelectric focusing of the conditioned medium revealed that the leucocytes produced two neutrophil chemotactic factors, leucocyte‐derived neutrophil chemotactic factor (LDNCF) 1 and LDNCF‐2. Treatment of the leucocytes with K‐252a, genistein, and H‐7, but not H‐89, inhibited production of both LDNCF‐1 and LDNCF‐2.
These results suggest that activation of tyrosine kinase and protein kinase C., but not cAMP‐dependent protein kinase, is responsible for the production of LDNCF‐1 and LDNCF‐2.
The steroidal anti‐inflammatory drug dexamethasone and the protein synthesis inhibitor cyclohex‐imide inhibited neutrophil chemotactic factor production in a concentration‐dependent manner. Time‐course experiments showed that the inhibitory effect by dexamethasone was apparent even 30min after the incubation.
Mechanism for inhibiting the production of LDNCF‐1 and LDNCF‐2 by dexamethasone is also discussed.
A1 adenosine receptor inhibition of cyclic AMP formation and radioligand binding in the guinea‐pig cerebral cortex
Authors: Alexander Stephen P.H. , Curtis Alistair R. , Kendall David A. , Hill Stephen J. 
Published: July 2012

A1 adenosine receptors were investigated by radioligand binding and functional studies in slices and particulate preparations from guinea‐pig cerebral cortex.
Binding of the adenosine receptor antagonist radioligand, 8‐cyclopentyl‐[3H]‐1,3‐dipropylxanthine (DPCPX) to guinea‐pig cerebral cortical membranes exhibited high density (1410 ± 241 fmol mg−1 protein) and high affinity (Kd 3.8 ± 0.3 nm).
[3H]‐DPCPX binding to guinea‐pig cerebral cortical membranes was displaced in a monophasic manner by adenosine receptor antagonists with the rank order of affinity (Ki values, nm): DPCPX (6) < xanthine amine congener (XAC, 153) < PD 115,199 (308).
Agonist displacement of [3H]‐DPCPX binding was biphasic and exhibited the following rank order at the low affinity site (Ki values): 2‐chloro‐N6‐cyclopentyl‐adenosine (CCPA, 513 nm) = N6‐R‐phenyl‐isopropyladenosine (R‐PIA, 526 nm) = M6‐cyclopentyladenosine (CPA, 532 nm) < 2‐chloroadenosine (2CA, 3.2 μm) = 5′‐N‐ethylcarboxamidoadenosine (NECA, 4.6 μm) < N6‐S‐phenylisopropyladenosine (S‐PIA, 19.9 μm).
In cerebral cortical slices, [3H]‐DPCPX binding was displaced by antagonists and agonists in an apparently monophasic manner with the rank order of affinity (Ki values, nm): DPCPX (14) < XAC (45) < R‐PIA (266) < PD 115,199 (666) < S‐PIA (21000).
Cyclic AMP accumulation stimulated by 30 μm forskolin in guinea‐pig cerebral cortical slices was inhibited by R‐PIA, CCPA and CPA up to 1 μm in a concentration‐dependent fashion with IQo values of 14, 18, and 22 nm, respectively. All three analogues inhibited the forskolin response to a similar extent (82–93% inhibition). NECA, S‐PIA and 2CA failed to inhibit the forskolin response, but rather enhanced the accumulation of cyclic AMP at concentrations of 100 nm or greater, presumably through activation of A2b adenosine receptors coupled to stimulation of cyclic AMP accumulation in guinea‐pig cerebral cortical slices.
The inhibition of forskolin‐stimulated cyclic AMP accumulation by CPA was antagonized with the rank order of affinity (Ki values, nm): DPCPX (6) < XAC (52) < PD 115,199 (505).
Xanthine‐based antagonists inhibited the adenosine receptor augmentation of histamine‐induced phosphoinositide turnover in guinea‐pig cerebral cortical slices with the rank order of affinity (Ki, nm): DPCPX (12) = XAC (17) < PD 155,199 (640).
In summary, we observe a good correlation between antagonist affinity at A1 receptors defined by radioligand binding, inhibition of cyclic AMP generation or augmentation of histamine‐evoked phosphoinositide turnover in guinea‐pig cerebral cortex.
Effects of β2‐adrenoceptor agonists on anti‐IgE‐induced contraction and smooth muscle reactivity in human airways
Authors: Gorenne Isabelle , Labat Carlos , Norel Xavier , De Montpreville Vincent , Guillet Marie‐Christine , Cavero Icilio , Brink Charles 
Published: July 2012

The β2‐adrenoceptor agonists, salbutamol, salmeterol and RP 58802 relaxed basal tone of human isolated bronchial smooth muscle. Salmeterol‐ and RP 58802‐induced relaxations persisted for more than 4h when the medium was constantly renewed after treatment.
Salbutamol, salmeterol and RP 58802 reversed histamine‐induced contractions in human airways (pD2 values: 6.15 ± 0.21, 6.00 ± 0.19 and 6.56 ± 0.12, respectively).
Anti‐IgE‐induced contractions were significantly inhibited immediately after pretreatment of preparations with β2‐adrenoceptor agonists (10 μm). However, when tissues were treated with β2‐agonists and then washed for a period of 4 h, salmeterol was the only agonist which significantly inhibited the anti‐IgE response.
Histamine response curves were shifted to the right immediately after pretreatment of tissues with the β2‐adrenoceptor agonists (10 μm; 20 min), but maximal contractions were not affected. After a 4 h washing period, the histamine curves were not significantly different from controls. Concentration‐effect curves to acetylcholine (ACh) or leukotriene C4 (LTC4) were not significantly modified after β2‐agonist pretreatment.
These results suggest that β2‐adrenoceptor agonists may prevent anti‐IgE‐induced contraction by inhibition of mediator release rather than alterations of those mechanisms involved in airway smooth muscle contraction.
4, 6‐Dibromo‐3‐hydroxycarbazole (an analogue of caffeine‐like Ca2+ releaser), a novel type of inhibitor of Ca2+‐induced Ca2+ release in skeletal muscle sarcoplasmic reticulum
Authors: Takahashi Yukiko , Furukawa Ken‐Ichi , Kozutsumi Daiske , Ishibashi Masami , Kobayashi Jun'ichi , Ohizumi Yasushi 
Published: July 2012

4,6‐Dibromo‐3‐hydroxycarbazole (DBHC) was synthesized as an analogue of bromoeudistomin D (BED), a powerful Ca2+ releaser, and its pharmacological properties were examined.
In Ca2+ electrode experiments, DBHC (100 μm) markedly inhibited Ca2+ release from the heavy fraction of sarcoplasmic reticulum (HSR) induced by caffeine (1 mm) and BED (10 μm).
DBHC (0.1 to 100 μm) inhibited 45Ca2+ release induced by Ca2+ from HSR in a concentration‐dependent manner.
DBHC (100 μm) abolished 45Ca2+ release induced by caffeine (1 mm) and BED (10 μm) in HSR.
Inhibitory effects of calcium‐induced calcium release (CICR) blockers such as procaine, ruthenium red and Mg2+ on 45Ca2+ release were clearly observed at Ca2+ concentrations from pCa 7 to pCa 5.5, and were decreased at Ca2+ concentrations higher than pCa 5.5 or lower than pCa 7. However, DBHC decreased Ca2+ release induced by Ca2+ over the wide range of extravesicular Ca2+ concentrations.
[3H]‐ryanodine binding to HSR was suppressed by ruthenium red, Mg2+ and procaine, but was not affected by DBHC up to 100 μm.
[3H]‐ryanodine binding to HSR was enhanced by caffeine and BED. DBHC antagonized the enhancement in a concentration‐dependent manner.
9‐[3H]‐Methyl‐7‐bromo‐eudistomin D, an 3H‐labelled analogue of BED, specifically bound to HSR. Both DBHC and caffeine increased the KD value without affecting the Bmax value, indicating a competitive mode of inhibition.
These results suggest that DBHC binds to the caffeine binding site to block Ca2+ release from HSR. This drug is a novel type of inhibitor for the CICR channels in SR and may provide a useful tool for clarifying the Ca2+ releasing mechanisms in SR.
The role of nitric oxide in the altered vascular reactivity of pregnancy in the rat
Authors: Nathan Lauren , Cuevas Janis , Chaudhuri Gautam 
Published: July 2012

Pregnancy is characterized by a decrease in systemic vascular resistance and a blunting of the angiotensin II (AII) pressor response. We studied the role of nitric oxide (NO) and prostanoids in these vascular changes of pregnancy in anaesthesized, ganglion blocked non‐pregnant and pregnant rats.
Inhibition of NO synthesis with NG‐nitro‐l‐arginine methyl ester (l‐NAME) led to an increase in mean arterial pressure (MAP) which was of a significantly greater magnitude in pregnant rats in late gestation than in non‐pregnant rats, or rats in mid‐gestation.
The pressor response to varying doses of AII was attenuated during late pregnancy, and this attenuation was partially reversed by l‐NAME.
The pressor response to varying doses of a vasocontrictor, phenylephrine (PE), was also attenuated in late pregnancy. However, this attenuation was not reversed by l‐NAME.
Inhibition of prostanoid biosynthesis with meclofenamate did not alter basal MAP, nor the pressor response to varying doses of AII or PE in pregnant and non‐pregnant animals.
It is concluded that (a) increased NO synthesis occurs during late gestation and contributes both to the decrease in systemic vascular resistance, as well as the blunting of the pressor response to AII during pregnancy, and (b) prostaglandins are not important in the maintenance of basal vascular tone, or the blunting of the pressor response to AII during pregnancy.
Suppression by the sumatriptan analogue, CP‐122,288 of c‐fos immunoreactivity in trigeminal nucleus caudalis induced by intracisternal capsaicin
Authors: Cutrer F. Michael , Schoenfeld David , Limmroth Volker , Panahian Nariman , Moskowitz Michael A. 
Published: July 2012

The effects of an intravenously administered sumatriptan analogue were examined on c‐fos‐like immunoreactivity (c‐fos‐LI), a marker of neuronal activation, evoked within trigeminal nucleus caudalis (TNC) and other brain stem regions 2 h after intracisternal injection of the irritant, capsaicin (0.1 ml, 0.1 mm), in pentobarbitone‐anaesthetized Hartley guinea‐pigs.
C‐fos‐LI was assessed in eighteen serial sections (50 μm) using a polyclonal antiserum. A weighted average, reflecting total expression within lamina I, IIo of TNC was obtained from three representative levels (i.e., at −0.225 mm, −2.475 mm and −6.975 mm.)
Capsaicin caused significant labelling within lamina I, IIo, a region containing axonal terminations of small unmyelinated C‐fibres, as well as within the nucleus of the solitary tract, area postrema and medial reticular nucleus. A similar distribution of positive cells was reported previously after intracisternal injection of other chemical irritants such as autologous blood or carrageenin.
Pretreatment with a conformationally restricted sumatriptan analogue (with some selectivity for 5‐HT1B and 5‐HT1D receptor subtypes) CP‐122,288, reduced the weighted average by approximately 50–60% (P<0.05) in lamina I, IIo at ≥ 100 pmol kg−1, i.v., but did not decrease cell number within area postrema, nucleus of the solitary tract or medial reticular nucleus. A similar pattern was reported previously following sumatriptan, dihydroergotamine or CP‐93,129 administration after noxious meningeal stimulation.
We conclude that modifications at the amino‐ethyl side chain of sumatriptan dramatically enhance the suppression of c‐fos expression within TNC, a finding consistent with its remarkable potency against neurogenic plasma protein extravasation within dura mater. CP‐122,288 and related analogues may serve as an important prototype for drug development in migraine and related headaches.
Further investigations into adenosine A1 receptor‐mediated contraction in rat colonic muscularis mucosae and its augmentation by certain alkylxanthine antagonists
Authors: Reeves J.J. , Jarvis J.E. , Sheehan M.J. , Strong P. 
Published: July 2012

The alkylxanthine antagonists, 8‐phenyltheophylline (8‐PT), 8‐p‐sulphophenyltheophylline (8‐SPT) and 1,3,7‐trimethylxanthine (caffeine) produced rightward displacements of contractile concentration‐effect curves to 5′‐N‐ethylcarboxamidoadenosine (NECA) in rat isolated colonic muscularis mucosae (RCMM) with concentration‐ratios consistent with adenosine receptor blockade. The non‐xanthine antagonist, 9 fluro‐2‐(2‐furyl)‐5,6‐dihydro [1,2,4] triazo to [1,5‐c]‐quinazin‐imine (CGS15943A) also antagonized contractions to NECA with an affinity (pKB 8.1–8.5) consistent with adenosine A1 receptor blockade.
In addition to producing rightward shifts of the concentration‐response curves, the maximum contractions to 5′‐N‐ethylcarboxamidoadenosine (NECA) were also markedly increased in the presence of 8‐PT (by 83 ± 16% at 1 μm), 8–SPT (by 37 ± 7% at 10 μm) and caffeine (by 45 ± 5% at 100 μm) but were unaffected by CGS15943A (at 0.01 and 0.03 μm).
As with NECA, the maximum contractions to the adenosine A1 receptor agonists R‐phenylisopropyladenosine (R‐PIA) and N‐[(1S, trans)‐2‐hydroxyclopentyl] adenosine (GR79236) were both antagonized and augmented by 8‐PT. In addition, the contractions to NECA in the presence of 8–PT (1 μm) were inhibited by nanomolar concentrations of 8‐cyclopentyl‐1,3‐dipropylxanthine (DPCPX).
The non‐selective phosphodiesterase (PDE) inhibitor, 3‐isobutyl‐1‐methylxanthine (1 μm) produced a marked increase in the NECA maximum without producing a rightward shift in the NECA curve, whereas a higher concentration (10 μm) virtually abolished responses. The PDE type III inhibitor, milrinone (1 μm), the type IV inhibitor, rolipram (10 μm), and the type V PDE inhibitor, zaprinast (3 μm), were all without effect on NECA responses in RCMM.
Partial inhibitions of contractions to NECA were produced by indomethacin (at 3 or 10 μm) or piroxicam (at 3 μm). Responses to GR79236 were also partially inhibited by indomethacin. In the presence of indomethacin, 8‐PT was still able to enhance markedly the maximum contractions obtained to NECA in RCMM.
The present study has shown that certain alkylxanthine antagonists (but not the non‐xanthine CGS15943A) produced a marked augmentation of adenosine A1 receptor‐mediated contractions in RCMM. The mechanism of this augmentation is, as yet, not known but is unlikely to result from inhibition of PDE. This study has also shown that adenosine A1 receptor‐induced contractions in RCMM are mediated, in part, via products of the cyclo‐oxygenase pathway.
Pharmacological characterization of α1‐adrenoceptor subtypes in rat heart: a binding study
Authors: Noguchi Hideki , Muraoka Ryusuke , Kigoshi Shigeru , Muramatsu Ikunobu 
Published: July 2012

The α1‐adrenoceptor subtypes of rat heart were characterized in binding experiments performed with [3H]‐prazosin as the radiolabel. The specific binding to the α1‐adrenoceptors was determined with 0.3 μm prazosin, because phentolamine (10 μm) was insufficient to inhibit completely the specific binding of high concentrations of [3H]‐prazosin.
In saturation experiments, [3H]‐prazosin bound to two distinct affinity sites (pKD = 10.39 and 8.19). The proportion of the low affinity sites was approximately 84% of total specific binding. Membranes pretreated with chloroethylclonidine (CEC, 10 μm) also showed two distinct affinity sites for [3H]‐prazosin, although the maximum numbers of high and low affinity sites were reduced by 86 and 64%, respectively.
In competition experiments, [3H]‐prazosin (100 pm) binding was inhibited by WB4101 (2‐(2,6‐dimethoxy‐phenoxyethyl)aminomethyl‐1,4‐benzodioxane) and 5‐methylurapidil. The inhibition curves displayed shallow slopes which could be subdivided into high and low affinity components (pK1 = 10.43 and 8.36 for WB4101, 8.62 and 6.61 for 5‐methylurapidil). However, unlabelled prazosin or HV723 (α‐ethyl‐3,4,5‐trimethoxy‐α‐(3‐((2‐(2‐methoxyphenoxy)‐ethyl)amino)propyl)benzeneacetonitrile fumarate) competed for [3H]‐prazosin binding monophasically (pK1 = 10.34 and 8.28, respectively). In CEC‐pretreated membranes, prazosin, WB4101, 5‐methylurapidil and HV723 antagonized the [3H]‐prazosin (100 pm) binding monophasically (pKI = 9.70, 9.56, 8.60 and 8.82, for each antagonist).
On the other hand, 1000 pm [3H]‐prazosin binding was inhibited by unlabelled prazosin biphasically (pKI = 10.49 and 8.49). HV723 did not discriminate both prazosin‐high and low affinity sites (pKI = 8.18).
These results suggest the presence of at least three distinct α1‐adrenoceptor subtypes in rat hearts (two prazosin‐high affinity sites and one prazosin‐low affinity site). According to the recent α1‐adrenoceptor subclassifications, one of the former two sites corresponds to the α1B subtype with low affinities for WB4101 and 5‐methylurapidil and sensitive to CEC, while another site with relatively high affinities for WB4101 and 5‐methylurapidil may be classical α1A, cloned α1C, α1D subtypes or their mixture. The prazosin‐low affinity site corresponds to putative α1L subtype with low affinity for HV723, which may be predominantly involved in the positive inotropic response to phenylephrine.
Inhibition of morphine withdrawal by the association of RB 101, an inhibitor of enkephalin catabolism, and the CCKB antagonist PD‐134,308
Authors: Maldonado Rafael , Valverde Olga , Ducos Bertrand , Blommaert Armand G , Fournie‐Zaluski Marie‐Claude , Roques Bernard P. 
Published: July 2012

The effects induced in rats on naloxone‐precipitated morphine withdrawal syndrome by the new mixed inhibitor of enkephalin catabolism able to cross the blood‐brain barrier RB 101 (N‐{(R,S)‐2‐benzyl‐3[(S)(2‐amino‐4‐methylthio)butyl dithio]‐1‐ox‐opropyl‐l‐phenylalanine benzyl ester) given alone or associated with the selective CCKB antagonist, PD‐134,308, were investigated.
The systemic administration of RB 101 (5, 10 and 20 mg kg−1, i.v.) elicited a significant decrease in 8 of the 14 withdrawal signs evaluated. PD‐134,308 (3 mg kg−1, i.p.) did not modify the expression of morphine abstinence when given alone, but induced a strong facilitation of RB 101 responses (12 of 14 withdrawal signs were decreased). This potentiation was particularly intense in peripherally mediated withdrawal signs.
In order to clarify the biochemical mechanisms implicated in these responses, the effects induced by the association of RB 101 and PD‐134,308 on the occupation of brain opioid receptors by endogenous enkephalins were also investigated in mice. PD‐134,308, as well as RB 101, inhibited [3H]‐diprenorphine binding to opioid receptors. These results suggest that an increase in endogenous enkephalin levels induced by PD‐134,308 could participate in the facilitation of RB 101 behavioural responses.
RB 101 has a promising potential role in the management of the opiate withdrawal syndrome. CCKB antagonists, such as PD‐134,308 may be useful in potentiating this anti‐withdrawal effect.
Functional effects of long‐term activation on human β2‐ and β3‐adrenoceptor signalling
Authors: Nantel François , Bouvier Michel , Strosberg A. Donny , Marullo Stefano 
Published: July 2012

The functional effects of long‐term activation of β‐adrenoceptors were investigated by measuring adenylyl cyclase activity, cyclic AMP accumulation and cyclic AMP‐dependent protein kinase activity in CHW and L cells expressing either human β2‐ or β3‐adrenoceptors.
Pre‐incubation of CHW and L cells expressing β2‐adrenoceptors with 10 μm isoprenaline for 24 h produced a marked reduction in the total receptor number and dramatically reduced the capacity of the receptor to stimulate adenylyl cyclase maximally.
In contrast, the ability of β3‐adrenoceptors to stimulate adenylyl cyclase maximally was not affected by pre‐incubation with the agonist in either cell type. However, a significant reduction of isoprenaline potency and a sustained down‐regulation of β3‐adrenoceptor number was observed in L but not in CHW cells.
Maximal levels of intracellular cyclic AMP concentrations were reached during the first hour of receptor activation with isoprenaline in all four cell lines. In the absence of phosphodiesterase inhibitors, cyclic AMP decreased to basal levels within 24 h of continuous stimulation. This phenomenon occurred more rapidly in cells expressing the β2‐ than the β3‐adrenoceptors.
These results confirm that, at the level of adenylyl cyclase stimulation and cyclic AMP accumulation, the β3‐adrenoceptor is more resistant than the β3‐adrenoceptor to long‐term desensitization. However, when cyclic AMP‐dependent protein kinase activity was considered, a 24 h stimulation of β2‐ and β3‐adrenoceptor expressing cells led to the desensitization of the kinase in L but not in CHW cells.
In conclusion, long‐term desensitization may have distinct functional effects on cell signalling depending on the receptor subtype and the cell type considered. These findings might have practical implications for future strategies involving long‐term therapies with receptor agonists.
Comparison of the pharmacological profile of S‐nitrosothiols, nitric oxide and the nitrergic neurotransmitter in the canine ileocolonic junction
Authors: De Man Joris G. , Boeckxstaens Guy E. , De Winter Benedicte Y. , Moreels Tom G. , Misset Menno E. , Herman Arnold G. , Pelckmans Paul A. 
Published: July 2012

1 In organ bath experiments, hydroquinone (30–100 μm) and hydroxocobalamin (30–100 μm) concentration‐dependently inhibited the relaxations induced by NO (0.3–30 μm) but not those by nitroglycerin (GTN, 1 μm) in the canine ileocolonic junction (ICJ). Hydroxocobalamin reduced the relaxation to low frequency (2 Hz) stimulation of the non‐adrenergic, non‐cholinergic (NANC) nerves, whereas hydroquinone only reduced the NANC nerve‐mediated relaxations to electrical stimulation at 16 Hz, 0.5 ms.2 Relaxations to S‐nitroso‐l‐cysteine (CysNO, 1–30 μm), or S‐nitroso‐N‐acetyl‐d,l‐penicillamine (SNAP, 1–30 μm) were not inhibited by hydroquinone (30–100 μm), hydroxocobalamin (30–100 μm), pyrogallol (30–100 μm) or l‐cysteine (1–3 μm). Hydroquinone (100 μm) only reduced the relaxation to 10 μm CysNO. Hydroxocobalamin, but not hydroquinone, pyrogallol or m‐cysteine, potentiated the relaxations to the lowest concentration (1 μm) of S‐nitrosoglutathione (GSNO, 1–30 μm).3 In the superfusion bioassay, hydroquinone (100 μm) and hydroxocobalamin (1 μm) concentration‐dependently inhibited the biological activity of authentic NO (1–4pmol) to the same extent as that of the transferable nitrergic factor, released from the canine ICJ in response to NANC nerve stimulation (8–16 Hz, 2 ms). Responses to GTN (10 pmol) or adenosine 5′‐triphosphate (10 nmol) were not affected.4 In conclusion, the nitrosothiols CysNO, SNAP and GSNO relax the canine ileocolonic junction, but these relaxations, pharmacologically, behave differently from the NANC nerve‐mediated relaxations. From the bioassay experiments, we conclude that the nitrergic factor, released in response to NANC nerve stimulation of the canine ICJ, behaves pharmacologically like NO but not like a nitrosothiol. Therefore, we suggest NO, and not CysNO, SNAP or GSNO as the inhibitory NANC neurotransmitter in the canine ICJ.