bluuebunny/crossref_metadata_2025 huggingface dataset:
Prostaglandin DP receptors positively coupled to adenylyl cyclase in embryonic bovine tracheal (EBTr) cells: pharmacological characterization using agonists and antagonists
Authors: Crider J Y , Griffin B W , Sharif N A
Published: January 2005

Various prostaglandin agonists representing various classes of receptor subtypes were evaluated for their ability to stimulate adenylyl cyclase via the endogenous DP receptor in embryonic bovine tracheal (EBTr) cells. Two antagonists were used to block the agonist‐induced cyclic AMP production.

ZK118182 (EC50=16±4 nM), RS‐93520 (EC50=23±4 nM), SQ27986 (EC50=33±9 nM), ZK110841 (EC50=33±5 nM), BW245C (EC50=59±19 nM) and PGD2 (EC50=101±10 nM) (n=4–70) were the most potent agonists. Whilst most compounds were full agonists (Emax=100% relative to PGD2), BW245C was significantly more efficacious than PGD2 (Emax=121±3%; P<0.001) and RS‐93520 appeared to be a partial agonist (Emax=64±9%; P<0.001).

Agonists from the EP (e.g. enprostil; misoprostol; butaprost), FP (e.g. cloprostenol; fluprostenol; PHXA85), IP (iloprost; PGI2) and TP (U46619) prostanoid receptor classes were weak agonists or inactive in the EBTr cell assay system.

The DP‐receptor antagonist, BWA868C, showed a competitive antagonist profile with pA2 values of 8.00±0.02 and 8.14±0.13 in Schild analyses with two structurally different agonists, BW245C and ZK118182, respectively (n=3). AH6809, another purported DP‐receptor antagonist, weakly inhibited PGD2‐ and ZK118182‐induced cyclic AMP production (Kis=808±193 nM and 782±178 nM, respectively).

The current studies have characterized the DP receptor positively coupled to adenylyl cyclase in EBTr cells using a wide range of agonist and antagonist prostaglandins. These data support the utility of the EBTr cell line as a useful tool for the evaluation of DP receptor agonists and antagonists and for profiling other classes of prostaglandins.

British Journal of Pharmacology (1999) 127, 204–210; doi:10.1038/sj.bjp.0702490
AMP is a partial agonist at the sheep cardiac ryanodine receptor
Authors: Ching Li Lien , Williams Alan J , Sitsapesan Rebecca
Published: January 2005

We have investigated the ability of AMP to modulate the native sheep cardiac ryanodine receptor (RyR) channel at various cytosolic [Ca2+]. Channels were incorporated into planar phospholipid bilayers and current fluctuations through the bilayer were monitored under voltage clamp conditions.

We demonstrate that AMP only exhibits agonist activity if the cytosolic [Ca2+] is sufficiently high. Even in the presence of a high cytosolic [Ca2+] (65 μM), AMP cannot fully open the channel and the maximum open probability (Po) observed is approximately 0.3 at 2 mM AMP.

Concentrations of AMP above the maximally activating level cause inactivation of the channel.

Our experiments indicate that AMP is an agonist with such low efficacy at the ATP sites on the cardiac RyR that it is effectively an antagonist of ATP‐induced increases in Po. Our study demonstrates that the number of phosphates attached to the 5′‐carbon of the ribose ring of adenine‐based compounds determines the efficacy of the ligand to increase the Po of the cardiac RyR. Substitution of groups at this position may lead to the identification of potent antagonists at ATP sites on RyR.

British Journal of Pharmacology (1999) 127, 161–171; doi:10.1038/sj.bjp.0702491
Potassium ions and endothelium‐derived hyperpolarizing factor in guinea‐pig carotid and porcine coronary arteries
Authors: Quignard Jean‐François , Félétou Michel , Thollon Catherine , Vilaine Jean‐Paul , Duhault Jacques , Vanhoutte Paul M
Published: January 2005

Experiments were designed to determine in two arteries (the guinea‐pig carotid and the porcine coronary arteries) whether or not the endothelium‐derived hyperpolarizing factor (EDHF) can be identified as potassium ions, and to determine whether or not the inwardly rectifying potassium current and the Na+/K+ pump are involved in the hyperpolarization mediated by EDHF.

The membrane potential of vascular smooth muscle cells was recorded with intracellular microelectrodes in the presence of Nω‐L‐nitro‐arginine (L‐NA) and indomethacin.

In vascular smooth muscle cells of guinea‐pig carotid and porcine coronary arteries, acetylcholine and bradykinin induced endothelium‐dependent hyperpolarizations (−18±1 mV, n=39 and −19±1 mV, n=7, respectively). The hyperpolarizations were not affected significantly by ouabain (1 μM), barium chloride (up to 100 μM) or the combination of ouabain plus barium.

In both arteries, increasing extracellular potassium concentration by 5 or 10 mM induced either depolarization or in a very few cases small hyperpolarizations which never exceeded 2 mV.

In isolated smooth muscle cells of the guinea‐pig carotid artery, patch‐clamp experiments shows that only 20% of the vascular smooth muscle cells expressed inwardly rectifying potassium channels. The current density recorded was low (0.5±0.1 pA pF−1, n=8).

These results indicate that, in two different vascular preparations, barium sensitive‐inwardly rectifying potassium conductance and the ouabain sensitive‐Na+/K+ pump are not involved in the EDHF‐mediated hyperpolarization. Furthermore, potassium did not mimic the effect of EDHF pointing out that potassium and EDHF are not the same entity in those arteries.

British Journal of Pharmacology (1999) 127, 27–34; doi:10.1038/sj.bjp.0702493
The effect of moxonidine on feeding and body fat in obese Zucker rats: role of hypothalamic NPY neurones
Authors: Bing Chen , King Peter , Pickavance Lucy , Brown Michael , Ziegler Dieter , Kaan Elbert , Williams Gareth
Published: January 2005

The antihypertensive agent moxonidine, an imidazoline Ii‐receptor agonist, also induces hypophagia and lowers body weight in the obese spontaneously hypertensive rat, but the central mediation of this action and the neuronal pathways that moxonidine may interact with are not known. We studied whether moxonidine has anti‐obesity effects in the genetically‐obese and insulin‐resistant fa/fa Zucker rat, and whether these are mediated through inhibition of the hypothalamic neuropeptide Y (NPY) neurones.

Lean and obese Zucker rats were given moxonidine (3 mg kg−1 day−1) or saline by gavage for 21 days.

Moxonidine decreased food intake throughout by 20% in obese rats (P<0.001) and by 8% in lean rats (P<0.001), and reduced weight gain that final body weight was 15% lower in obese (P<0.001) and 7% lower in lean (P<0.01) rats than their untreated controls. Plasma insulin and leptin levels were decreased in moxonidine‐treated obese rats (P<0.01 and P<0.05), but unchanged in treated lean rats. Uncoupling protein‐1 gene expression in brown adipose tissue was stimulated by 40–50% (P0.05) in both obese and lean animals given moxonidine. Obese animals given moxonidine showed a 37% reduction in hypothalamic NPY mRNA levels (P=0.01), together with significantly increased NPY concentrations in the paraventricular nucleus (P<0.05), but no changes in the arcuate nucleus or other nuclei; this is consistent with reduced NPY synthesis in the arcuate nucleus and blocked release of NPY in the paraventricular nucleus. In lean animals, moxonidine did not affect NPY levels or NPY mRNA.

The hypophagic, thermogenic and anti‐obesity effects of moxonidine in obese Zucker rats may be partly due to inhibition of the NPY neurones, whose inappropriate overactivity may underlie obesity in this model.

British Journal of Pharmacology (1999) 127, 35–42; doi:10.1038/sj.bjp.0702494
Effects of the soluble guanylyl cyclase activator, YC‐1, on vascular tone, cyclic GMP levels and phosphodiesterase activity
Authors: Galle Jan , Zabel Ulrike , Hübner Ulrich , Hatzelmann Armin , Wagner Birgit , Wanner Christoph , Schmidt Harald H H W
Published: January 2005

The vasomotor and cyclic GMP‐elevating activity of YC‐1, a novel NO‐independent activator of soluble guanylyl cyclase (sGC), was studied in isolated rabbit aortic rings and compared to that of the NO donor compounds sodium nitroprusside (SNP) and NOC 18.

Similarly to SNP and NOC 18, YC‐1 (0.3–300 μM) caused a concentration‐dependent, endothelium‐independent relaxation that was greatly reduced by the sGC inhibitor 1‐H‐[1,2,4]oxadiazole[4,3‐a]quinoxalin‐1‐one (ODQ 10 μM; 59% inhibition of dilation induced by 100 μM YC‐1) suggesting the activation of sGC as one mechanism of action.

Preincubation with YC‐1 (3 and 30 μM) significantly increased the maximal dilator responses mediated by endogenous NO in aortic rings that was released upon exposure to acetylcholine, and enhanced the dilator response to the exogenous NO‐donors, SNP and NOC 18, by almost two orders of magnitude.

Vasoactivity induced by SNP and YC‐1 displayed different kinetics as evidenced by a long‐lasting inhibition by YC‐1 (300 μM) on the phenylephrine (PE)‐induced contractile response, which was not fully reversible even after extensive washout (150 min) of YC‐1, and was accompanied by a long‐lasting elevation of intracellular cyclic GMP content. In contrast, SNP (30 μM) had no effect on the vasoconstrictor potency of PE, and increases in intravascular cyclic GMP levels were readily reversed after washout of this NO donor compound.

Surprisingly, YC‐1 not only activated sGC, but also affected cyclic GMP metabolism, as it inhibited both cyclic GMP break down in aortic extracts and the activity of phosphodiesterase isoforms 1–5 in vitro.

In conclusion, YC‐1 caused persistent elevation of intravascular cyclic GMP levels in vivo by activating sGC and inhibiting cyclic GMP break down. Thus, YC‐1 is a highly effective vasodilator compound with a prolonged duration of action, and mechanisms that are unprecedented for any previously known sGC activator.

British Journal of Pharmacology (1999) 127, 195–203; doi:10.1038/sj.bjp.0702495
Inhibition of HERG channels stably expressed in a mammalian cell line by the antianginal agent perhexiline maleate
Authors: Walker B D , Valenzuela S M , Singleton C B , Tie H , Bursill J A , Wyse K R , Qiu M R , Breit S N , Campbell T J
Published: January 2005

Perhexiline has been used as an anti‐anginal agent for over 25 years, and is known to cause QT prolongation and torsades de pointes. We hypothesized that the cellular basis for these effects was blockade of IKr.

A stable transfection of HERG into a CHO‐K1 cell line produced a delayed rectifier, potassium channel with similar properties to those reported for transient expression in Xenopus oocytes.

Perhexiline caused voltage‐ and frequency‐dependent block of HERG (IC50 7.8 μM).

The rate of inactivation was increased and there was a 10 mV hyperpolarizing shift in the voltage‐dependence of steady‐state inactivation, suggestive of binding to the inactivated state.

In conclusion, perhexiline potently inhibits transfected HERG channels and this is the probable mechanism for QT prolongation and torsades de pointes. Channel blockade shows greatest affinity for the inactivated state.

British Journal of Pharmacology (1999) 127, 243–251; doi:10.1038/sj.bjp.0702502
Antagonistic action of pitrazepin on human and rat GABAA receptors
Authors: Demuro Angelo , Martinez‐Torres Ataulfo , Francesconi Walter , Miledi Ricardo
Published: January 2005

Pitrazepin, 3‐(piperazinyl‐1)‐9H‐dibenz(c,f) triazolo(4,5‐a)azepin is a piperazine antagonist of GABA in a variety of electrophysiological and in vitro binding studies involving GABA and glycine receptors. In the present study we have investigated the effects of pitrazepin, and the GABAA antagonist bicuculline, on membrane currents elicited by GABA in Xenopus oocytes injected with rat cerebral cortex mRNA or cDNAs encoding α1β2 or α1β2γ2S human GABAA receptor subunits.

The three types of GABAA receptors expressed were reversibly antagonized by bicuculline and pitrazepin in a concentration‐dependent manner. GABA dose‐current response curves for the three types of receptors were shifted to the right, in a parallel manner, by increasing concentrations of pitrazepin.

Schild analyses gave pA2 values of 6.42±0.62, n=4, 6.41±1.2, n=5 and 6.21±1.24, n=6, in oocytes expressing rat cerebral cortex, α1β2 or α1β2γ2S human GABAA receptors respectively (values are given as means±s.e.mean), and the Hill coefficients were all close to unity. All this is consistent with the notion that pitrazepin acts as a competitive antagonist of these GABAA receptors; and that their antagonism by pitrazepin is not strongly dependent on the subunit composition of the receptors here studied.

Since pitrazepin has been reported to act also at the benzodiazepine binding site, we studied the effect of the benzodiazepine antagonist Ro 15–1788 (flumazenil) on the inhibition of α1β2γ2S receptors by pitrazepin. Co‐application of Ro 15–1788 did not alter the inhibiting effect of pitrazepin. Moreover, pitrazepin did not antagonize the potentiation of GABA‐currents by flunitrazepam. All this suggests that pitrazepin does not affect the GABA receptor‐chloride channel by interacting with the benzodiazepine receptor site.

British Journal of Pharmacology (1999) 127, 57–64; doi:10.1038/sj.bjp.0702504
Characterization of the cyclic nucleotide phosphodiesterase subtypes involved in the regulation of the L‐type Ca2+ current in rat ventricular myocytes
Authors: Verde Ignacio , Vandecasteele Grégoire , Lezoualc'h Frank , Fischmeister Rodolphe
Published: January 2005

The effects of several phosphodiesterase (PDE) inhibitors on the L‐type Ca current (ICa) and intracellular cyclic AMP concentration ([cAMP]i) were examined in isolated rat ventricular myocytes. The presence of mRNA transcripts encoding for the different cardiac PDE subtypes was confirmed by RT–PCR.

IBMX (100 μM), a broad‐spectrum PDE inhibitor, increased basal ICa by 120% and [cAMP]i by 70%, similarly to a saturating concentration of the β‐adrenoceptor agonist isoprenaline (1 μM). However, MIMX (1 μM), a PDE1 inhibitor, EHNA (10 μM), a PDE2 inhibitor, cilostamide (0.1 μM), a PDE3 inhibitor, or Ro 20–1724 (0.1 μM), a PDE4 inhibitor, had no effect on basal ICa and little stimulatory effects on [cAMP]i (20–30%).

Each selective PDE inhibitor was then tested in the presence of another inhibitor to examine whether a concomitant inhibition of two PDE subtypes had any effect on ICa or [cAMP]i. While all combinations tested significantly increased [cAMP]i (40–50%), only cilostamide (0.1 μM)+Ro20‐1724 (0.1 μM) produced a significant stimulation of ICa (50%). Addition of EHNA (10 μM) to this mix increased ICa to 110% and [cAMP]i to 70% above basal, i.e. to similar levels as obtained with IBMX (100 μM) or isoprenaline (1 μM).

When tested on top of a sub‐maximal concentration of isoprenaline (1 nM), which increased ICa by (∼40% and had negligible effect on [cAMP]i, each selective PDE inhibitor induced a clear stimulation of [cAMP]i and an additional increase in ICa. Maximal effects on ICa were ∼8% for MIMX (3 μM), ∼20% for EHNA (1–3 μM), ∼30% for cilostamide (0.3–1 μM) and ∼50% for Ro20‐1724 (0.1 μM).

Our results demonstrate that PDE1‐4 subtypes regulate ICa in rat ventricular myocytes. While PDE3 and PDE4 are the dominant PDE subtypes involved in the regulation of basal ICa, all four PDE subtypes determine the response of ICa to a stimulus activating cyclic AMP production, with the rank order of potency PDE4>PDE3>PDE2>PDE1.

British Journal of Pharmacology (1999) 127, 65–74; doi:10.1038/sj.bjp.0702506
Distinct effects of ceramide‐generating pathways in prostate adenocarcinoma cells
Authors: Condorelli Fabrizio , Canonico Pier Luigi , Sortino Maria Angela
Published: January 2005

Ceramide, generated by the hydrolysis of sphingomyelin, mediates the actions of several cytokines such as tumour necrosis factor‐α (TNF‐α) interferon‐γ and interleukin‐1β (IL‐1β), including their inhibitory effect on tumour proliferation. We have evaluated the role of ceramide in the proliferation of prostate cancer by using the human prostate adenocarcinoma LNCaP cell line.

Treatment of LNCaP cells with neutral or acidic sphingomyelinase or addition of C8‐ or C2‐ceramide, two cell permeable analogues of endogenous ceramide, induced a profound inhibition of cell proliferation. This effect appeared after 24 h, was still present after 72 h of exposure to the drugs and exhibited concentration‐dependency (10–200 and 5–200 mU ml−1 for neutral and acidic sphingomyelinase, respectively, and 1–25 μM for C8‐ceramide).

The inhibitory effect on cell growth caused by neutral sphingomyelinase and ceramides was rapidly reversible as LNCaP cells rapidly regained their previous proliferation rate following withdrawal of the treatment.

IL‐1β produced profound inhibition of LNCaP cell proliferation and caused enhanced ceramide formation.

No clear features of apoptotic cell death were detectable by either oligonucleosome formation, cytofluorimetric analysis or nuclear staining following exposure of LNCaP cells to neutral sphingomyelinase, ceramide or IL‐1β. However, clear changes in LNCaP cell cycle distribution were detectable following these treatments. In contrast, treatment with acidic sphingomyelinase or TNF‐α induced apoptotic death detectable by flow cytometric analysis and bisbenzimide staining.

In conclusion, our data demonstrate that preferential activation of distinct enzymatic pathways by cytokines may lead to different outcomes in the viability of LNCaP cells.

British Journal of Pharmacology (1999) 127, 75–84; doi:10.1038/sj.bjp.0702507
Role of the medial prefrontal cortex in 5‐HT1A receptor‐induced inhibition of 5‐HT neuronal activity in the rat
Authors: Hajós Mihály , Hajós‐Korcsok Éva , Sharp Trevor
Published: January 2005

We examined the involvement of the frontal cortex in the 5‐HT1A receptor‐induced inhibition of 5‐HT neurones in the dorsal raphe nucleus (DRN) of the anaesthetized rat using single‐unit recordings complemented by Fos‐immunocytochemistry.

Both transection of the frontal cortex as well as ablation of the medial region of the prefrontal cortex (mPFC) significantly attenuated the inhibition of 5‐HT neurones induced by systemic administration of the 5‐HT1A receptor agonist, 8‐OH‐DPAT (0.5–16 μg kg−1, i.v.). In comparison, the response to 8‐OH‐DPAT was not altered by ablation of the parietal cortex. The inhibitory effect of 8‐OH‐DPAT was reversed by the 5‐HT1A receptor antagonist, WAY 100635 (0.1 mg kg−1, i.v.) in all neurones tested.

In contrast, cortical transection did not alter the sensitivity of 5‐HT neurones to iontophoretic application of 8‐OH‐DPAT into the DRN. Similarly, cortical transection did not alter the sensitivity of 5‐HT neurones to systemic administration of the selective 5‐HT reuptake inhibitor, paroxetine (0.1–0.8 mg kg−1, i.v.).

8‐OH‐DPAT evoked excitation of mPFC neurones at doses (0.5–32 μg kg−1, i.v.) in the range of those which inhibited 5‐HT cell firing. At higher doses (32–512 μg kg−1, i.v.) 8‐OH‐DPAT inhibited mPFC neurones. 8‐OH‐DPAT (0.1 mg kg−1, s.c.) also induced Fos expression in the mPFC. The neuronal excitation and inhibition, as well as the Fos expression, were antagonized by WAY 100635.

These data add further support to the view that the inhibitory effect of 5‐HT1A receptor agonists on the firing activity of DRN 5‐HT neurones involves, in part, activation of a 5‐HT1A receptor‐mediated postsynaptic feedback loop centred on the mPFC.

British Journal of Pharmacology (1999) 126, 1741–1750; doi:10.1038/sj.bjp.0702510
Anti‐inflammatory activity of c(ILDV‐NH(CH2)5CO), a novel, selective, cyclic peptide inhibitor of VLA‐4‐mediated cell adhesion
Authors: Haworth Duncan , Rees Amanda , Alcock Peter J , Wood Linda J , Dutta Anand S , Gormley James J , Jones Huw B , Jamieson Alec , Reilly Christopher F
Published: January 2005

Small, N‐ to C‐terminal cyclized peptides containing the leucyl‐aspartyl‐valine (LDV) motif from fibronectin connecting segment‐1 (CS‐1) have been investigated for their effects on the adhesion of human T‐lymphoblastic leukaemia cells (MOLT‐4) to human plasma fibronectin in vitro mediated by the integrin Very Late Antigen (VLA)‐4 (α4β1, CD49d/CD29).

Cyclo(‐isoleucyl‐leucyl‐aspartyl‐valyl‐aminohexanoyl‐) (c(ILDV‐NH(CH2)5CO)) was approximately 5 fold more potent (IC50 3.6±0.44 μM) than the 25‐amino acid linear CS‐1 peptide. Cyclic peptides containing two more or one less methylene groups had similar potency to c(ILDV‐NH(CH2)5CO) while a compound containing three less methylene groups, c(ILDV‐NH(CH2)2CO), was inactive at 100 μM.

c(ILDV‐NH(CH2)5CO) had little effect on cell adhesion mediated by two other integrins, VLA‐5 (α5,β1, CD49e/CD29) (K562 cell adhesion to fibronectin) or Leukocyte Function Associated molecule‐1 (LFA‐1, αLβ2, CD11a/CD18) (U937 cell adhesion to Chinese hamster ovary cells transfected with intercellular adhesion molecule‐1) at concentrations up to 300 μM.

c(ILDV‐NH(CH2)5CO) inhibited ovalbumin delayed‐type hypersensitivity or oxazolone contact hypersensitivity in Balb/c mice when dosed continuously from subcutaneous osmotic mini‐pumps (0.1–10 mg kg−1 day−1). Maximum inhibition (approximately 40%) was similar to that caused by the monoclonal antibody PS/2 (7.5 mg kg−1 i.v.) directed against the α4 integrin subunit.

c(ILDV‐NH(CH2)5CO) also inhibited oxazolone contact hypersensitivity when dosed intravenously 20 h after oxazolone challenge (1–10 mg kg−1). Ear swelling was reduced at 3 h and 4 h but not at 1 h and 2 h post‐dose (10 mg kg−1).

Small molecule VLA‐4 inhibitors derived from c(ILDV‐NH(CH2)5CO) may be useful as anti‐inflammatory agents.

British Journal of Pharmacology (1999) 126, 1751–1760; doi:10.1038/sj.bjp.0702511
Respiratory action of capsaicin microinjected into the nucleus of the solitary tract: involvement of vanilloid and tachykinin receptors
Authors: Mazzone Stuart B , Geraghty Dominic P
Published: January 2005

The respiratory response to microinjection of capsaicin into the commissural nucleus of the solitary tract (cNTS) of urethane‐anaesthetized rats was investigated in the absence and presence of the competitive vanilloid (capsaicin) antagonist, capsazepine, and selective tachykinin NK1, NK2 and NK3 antagonists (RP 67580, SR 48968 and SR 142801, respectively).

Microinjection of capsaicin reduced respiratory frequency but not tidal volume (VT), leading to an overall reduction in minute ventilation (V{dot above}E). The effect was dose‐dependent between 0.5 and 2 nmol capsaicin. Doses greater than 2 nmol produced apnoea. Tachyphylaxis was observed following repeated injection of capsaicin (1 nmol, 30 min apart).

Capsazepine (1 nmol) had no effect on frequency or VT when injected alone but completely blocked the respiratory response to capsaicin (1 nmol).

RP 67580 (1 but not 5 nmol) alone depressed frequency and VT slightly. Moreover, RP 67580 appeared to potentiate the bradypnoeic effect of capsaicin. In contrast, SR 48968 and SR 142801 (1 and 5 nmol) alone had no significant effect on respiration. However, both agents significantly attenuated the reduction in frequency produced by capsaicin.

In conclusion, microinjection of capsaicin into the cNTS decreases overall ventilation, primarily by reducing frequency. The action of capsaicin appears from the data to be mediated by vanilloid receptors since it is blocked by the competitive vanilloid antagonist capsazepine and is subject to tachyphylaxis. However, since NK2 (SR 48968) and NK3 (SR 142801) receptor antagonists block the actions of capsaicin, we propose that capsaicin acts also by releasing tachykinins from central afferent terminals in the cNTS.

British Journal of Pharmacology (1999) 127, 473–481; doi:10.1038/sj.bjp.0702522
Control of glutamate release by calcium channels and κ‐opioid receptors in rodent and primate striatum
Authors: Hill M P , Brotchie J M
Published: January 2005

The modulation of depolarization (4‐aminopyridine, 2 mM)‐evoked endogenous glutamate release by κ‐opioid receptor activation and blockade of voltage‐dependent Ca2+‐channels has been investigated in synaptosomes prepared from rat and marmoset striatum.

4‐Aminopyridine (4‐AP)‐stimulated, Ca2+‐dependent glutamate release was inhibited by enadoline, a selective κ‐opioid receptor agonist, in a concentration‐dependent and nor‐binaltorphimine (nor‐BNI, selective κ‐opioid receptor antagonist)‐sensitive manner in rat (IC50=4.4±0.4 μM) and marmoset (IC50=2.9±0.7 μM) striatal synaptosomes. However, in the marmoset, there was a significant (∼23%) nor‐BNI‐insensitive component.

In rat striatal synaptosomes, the Ca2+‐channel antagonists ω‐agatoxin‐IVA (P/Q‐type blocker), ω‐conotoxin‐MVIIC (N/P/Q‐type blocker) and ω‐conotoxin‐GVIA (N‐type blocker) reduced 4‐AP‐stimulated, Ca2+‐dependent glutamate release in a concentration‐dependent manner with IC50 values of 6.5±0.9 nM, 75.5±5.9 nM and 106.5±8.7 nM, respectively. In marmoset striatal synaptosomes, 4‐AP‐stimulated, Ca2+‐dependent glutamate release was significantly inhibited by ω‐agatoxin‐IVA (30 nM, 57.6±2.3%, inhibition), ω‐conotoxin‐MVIIC (300 nM, 57.8±3.1%) and ω‐conotoxin‐GVIA (1 μM, 56.7±2%).

Studies utilizing combinations of Ca2+‐channel antagonists suggests that in the rat striatum, two relatively distinct pools of glutamate, released by activation of either P or Q‐type Ca2+‐channels, exist. In contrast, in the primate there is much overlap between the glutamate released by P and Q‐type Ca2+‐channel activation.

Studies using combinations of enadoline and the Ca2+‐channel antagonists suggest that enadoline‐induced inhibition of glutamate release occurs primarily via reduction of Ca2+‐influx through P‐type Ca2+‐channels in the rat but via N‐type Ca2+‐channels in the marmoset.

In conclusion, the results presented suggest that there are species differences in the control of glutamate release by κ‐opioid receptors and Ca2+‐channels.

British Journal of Pharmacology (1999) 127, 275–283; doi:10.1038/sj.bjp.0702523
The bradykinin B1 receptor and the central regulation of blood pressure in spontaneously hypertensive rats
Authors: Emanueli Costanza , Chao Julie , Regoli Domenico , Chao Lee , Ni Aiguo , Madeddu Paolo
Published: January 2005

We evaluated if the brain bradykinin (BK) B1 receptor is involved in the regulation of blood pressure (BP) in conscious rats.

Basal mean BP and HR were 115±2 and 165±3 mmHg and 345±10 and 410±14 beats min−1 in Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR), respectively. Intracerebroventricular (i.c.v.) injection of 1 nmol B1 receptor agonist Lys‐desArg9‐BK significantly increased the BP of WKY and SHR by 7±1 and 19±2 mmHg, respectively. One nmol Sar[D‐Phe8]‐desArg9‐BK, a kininase‐resistant B1 agonist, increased the BP of WKY and SHR by 19±2 and 17±2 mmHg, respectively and reduced HR in both strains.

I.c.v. injection of 0.01 nmol B1 antagonists, LysLeu8‐desArg9‐BK or AcLys[D‐βNal7,Ile8]‐desArg9‐BK (R715), significantly decreased mean BP in SHR (by 9±2 mmHg the former and 14±3 mmHg the latter compound), but not in WKY. In SHR, the BP response to R715 was associated to tachycardia.

I.c.v. Captopril, a kininase inhibitor, increased the BP of SHR, this response being partially prevented by i.c.v. R715 and reversed into a vasodepressor effect by R715 in combination with the B2 antagonist Icatibant.

I.c.v. antisense oligodeoxynucleotides (ODNs) targeted to the B1 receptor mRNA decreased BP in SHR, but not in WKY. HR was not altered in either strain. Distribution of fluorescein‐conjugated ODNs was detected in brain areas surrounding cerebral ventricles.

Our results indicate that the brain B1 receptor participates in the regulation of BP. Activation of the B1 receptor by kinin metabolites could participate in the pathogenesis of hypertension in SHR.

British Journal of Pharmacology (1999) 126, 1769–1776; doi:10.1038/sj.bjp.0702527
2‐Phenyl‐imidazo[1,2‐a]pyridine derivatives as ligands for peripheral benzodiazepine receptors: stimulation of neurosteroid synthesis and anticonflict action in rats
Authors: Serra Mariangela , Madau Paola , Chessa Maria Francesca , Caddeo Monica , Sanna Enrico , Trapani Giuseppe , Franco Massimo , Liso Gaetano , Purdy Robert H , Barbaccia Maria Luisa , Biggio Giovanni
Published: January 2005

Selective activation of peripheral benzodiazepine receptors (PBRs) in adrenal cells and brain oligodendrocytes promotes steroidogenesis. Three 2‐phenyl‐imidazo[1,2‐a]pyridine derivatives (CB 34, CB 50 and CB 54) have now been investigated with regard to their selectivity for PBRs and their ability to stimulate central and peripheral steroidogenesis in rats.

The three CB compounds (10−10–10−4 M) potently inhibited the binding of the PBR ligand [3H]‐PK 11195 to brain and ovary membranes in vitro, without substantially affecting [3H]‐flunitrazepam binding to central benzodiazepine receptors. These compounds (10−7–10−4 M) also had little or no marked effects on GABA‐evoked Cl− currents in voltage‐clamped Xenopus oocytes expressing human α1β2γ2S GABAA receptors. In addition, they failed to affect ligands binding to GABAB, D1/D2 dopamine, muscarinic acetylcholine, N‐methyl‐D‐aspartic acid and opiate receptors.

Intraperitoneal administration of CB compounds (3–50 mg kg−1) induced a dose‐dependent increase in the concentrations of neuroactive steroids in plasma and brain. The brain concentrations of pregnenolone, progesterone, allopregnanolone and allotetrahydrodeoxycorticosterone (THDOC) showed maximal increases in 96±3, 126±14, 110±12 and 70±13% above control, respectively, 30 to 60 min after injection of CB 34 (25 mg kg−1). CB 34 also increased the brain concentrations of neuroactive steroids in adrenalectomized‐orchiectomized rats, although to a lesser extent than in sham‐operated animals, suggesting that CB compounds stimulate brain steroidogenesis independently of their effects on peripheral tissues.

The increase in brain and plasma neurosteroid content induced by CB 34 was associated with a marked anticonflict effect in the Vogel test. Our results indicate that the three CB compounds tested are specific and potent agonists at peripheral benzodiazepine receptors, and that they stimulate steroidogenesis in both the brain and periphery.

British Journal of Pharmacology (1999) 127, 177–187; doi:10.1038/sj.bjp.0702530
Differential pharmacology between the guinea‐pig and the gorilla 5‐HT1D receptor as probed with isochromans (5‐HT1D‐selective ligands)
Authors: Pregenzer Jeffrey F , Alberts Glen L , Im Wha Bin , Slightom Jerry L , Ennis Michael D , Hoffman Robert L , Ghazal Nabil B , TenBrink Ruth E
Published: January 2005

Both the 5‐HT1D and 5‐HT1B receptors are implicated in migraine pathophysiology. Recently isochromans have been discovered to bind primate 5‐HT1D receptors with much higher affinity than 5‐HT1B receptors. In the guinea‐pig, a primary animal model for anti‐migraine drug testing, however, isochromans bound the 5‐HT1D receptor with lower affinity than the gorilla receptor.

This species‐specific pharmacology was investigated, using site‐directed mutagenesis on cloned guinea‐pig receptors heterologously expressed in human embryonic kidney 293 cells. Mutations of threonine 100 and arginine 102 at the extracellular side of transmembrane II of the guinea‐pig 5‐HT1D receptor to the corresponding primate residues, isoleucine and histidine, respectively, enhanced its affinity for isochromans to that of the gorilla receptor, with little effects on its affinities for serotonin, sumatriptan and metergoline. Free energy change from the R102H mutation was about twice as much as that from the T100I mutation.

For G protein‐coupling, serotonin marginally enhanced GTPγ35S binding in membranes expressing the guinea‐pig 5‐HT1D receptor and its mutants, but robustly in membranes expressing the gorilla receptor. Sumatriptan enhanced GTPγ35S binding in the latter nearly as much as serotonin, and several isochromans by 30–60% of serotonin.

We discovered key differences in the function and binding properties of guinea‐pig and gorilla 5‐HT1D receptors, and identified contributions of I100 and H102 of primate 5‐HT1D receptors to isochroman binding. Among common experimental animals, only the rabbit shares I100 and H102 with primates, and could be useful for studying isochroman actions in vivo.

British Journal of Pharmacology (1999) 127, 468–472; doi:10.1038/sj.bjp.0702532
Suppressive effect of distinct bradykinin B2 receptor antagonist on allergen‐evoked exudation and leukocyte infiltration in sensitized rats
Authors: Bandeira‐Melo Christianne , Calheiros Andrea S , Silva Patricia M R , Cordeiro Renato S B , Teixeira Mauro M , Martins Marco A
Published: January 2005

Bradykinin is suggested to play a role in the pathophysiology of several acute and chronic diseases, including allergic disorders such as asthma. In the present study, we have investigated the importance of bradykinin in mediating allergic inflammation in rats.

To this end we have tested the effects of the B2 receptor antagonists Hoe 140, FR173657 or FR172357 on the pleural inflammatory response triggered by intrapleural (i.pl.) injection of allergen (ovalbumin, 12 μg cavity−1) in 14 day‐actively sensitized Wistar rats. Analysis of the pleural fluid effluent revealed a sequence of mast cell‐dependent inflammatory events, including early protein exudation and neutrophilia and late pleural eosinophil influx.

Local treatment with Hoe 140 (0.1 and 1 μg cavity−1), FR173657 (1 and 10 μg cavity−1) or FR172357 (1 and 10 μg cavity−1) inhibited dose‐dependently allergen‐induced mast cell activation with impairment of pleural plasma leakage, neutrophil accumulation and late eosinophil influx.

Moreover, the B2 receptor antagonists also dose‐dependently inhibited the allergic like inflammatory pleurisy triggered by bradykinin (50 μg cavity−1), which is characterized by acute mast cell degranulation, protein leakage and pleural eosinophil infiltration.

Taken together, our findings provide substantial evidence to suggest that bradykinin acting on its B2 receptors play a critical role in mediating allergic mast cell‐dependent inflammation in rats, and suggest that B2 receptor antagonists may be useful therapeutically to control allergic dysfunction.

British Journal of Pharmacology (1999) 127, 315–320; doi:10.1038/sj.bjp.0702536
Tonic inhibitory action by nitric oxide on spontaneous mechanical activity in rat proximal colon: involvement of cyclic GMP and apamin‐sensitive K+ channels
Authors: Mulè F , D'Angelo S , Serio R
Published: January 2005

The cellular mechanisms by which endogenous nitric oxide (NO) modulates spontaneous motility were investigated in rat isolated proximal colon. The mechanical activity was detected as changes in intraluminal pressure.

Apamin (1–100 nM) produced a concentration‐dependent increase in the amplitude of the spontaneous pressure waves. The maximal contractile effect was of the same degree as that produced by Nω‐nitro‐L‐arginine methyl ester (L‐NAME) (100 μM) and the joint application of apamin plus L‐NAME had no additive effects. Apamin (0.1 μM) reduced the inhibitory effects (i.e. reduction in the amplitude of the pressure waves) induced by sodium nitroprusside (SNP) (1 nM–10 μM) or 8‐Br‐cyclic GMP (1–100 μM).

1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ) (0.1–5 μM), inhibitor of NO‐stimulated guanylate cyclase, produced a concentration‐dependent increase of the spontaneous contractions. ODQ (1 μM) in the presence of apamin (0.1 μM) did not produce any further increase in the contraction amplitude, whereas after L‐NAME (100 μM) it decreased the spontaneous contractions. ODQ (1 μM) reduced the SNP inhibitory effects.

Zaprinast (1–50 μM), inhibitor of cyclic GMP phosphodiesterase, produced a concentration‐dependent decrease of the spontaneous contractions. The effects of zaprinast were significantly reduced in the presence of apamin (0.1 μM) or L‐NAME (100 μM).

These results suggest that small conductance Ca2+‐dependent K+ channels and cyclic GMP are involved in the modulation of the spontaneous contractile activity in rat proximal colon. Cyclic GMP production system and opening of apamin‐sensitive K+ channels appear to work sequentially in transducing an endogenous NO signal.

British Journal of Pharmacology (1999) 127, 514–520; doi:10.1038/sj.bjp.0702537
In vitroα1‐adrenoceptor pharmacology of Ro 70–0004 and RS‐100329, novel α1A‐adrenoceptor selective antagonists
Authors: Williams T J , Blue D R , Daniels D V , Davis B , Elworthy T , Gever J R , Kava M S , Morgans D , Padilla F , Tassa S , Vimont R L , Chapple C R , Chess‐Williams R , Eglen R M , Clarke D E , Ford A P D W
Published: January 2005

It has been hypothesized that in patients with benign prostatic hyperplasia, selective antagonism of the α1A‐adrenoceptor‐mediated contraction of lower urinary tract tissues may, via a selective relief of outlet obstruction, lead to an improvement in symptoms.

The present study describes the α1‐adrenoceptor (α1‐AR) subtype selectivities of two novel α1‐AR antagonists, Ro 70‐0004 (aka RS‐100975) and a structurally‐related compound RS‐100329, and compares them with those of prazosin and tamsulosin. Radioligand binding and second‐messenger studies in intact CHO‐K1 cells expressing human cloned α1A‐, α1B‐ and α1D‐AR showed nanomolar affinity and significant α1A‐AR subtype selectivity for both Ro 70‐0004 (pKi 8.9: 60 and 50 fold selectivity) and RS‐100329 (pKi 9.6: 126 and 50 fold selectivity) over the α1B‐ and α1D‐AR subtypes respectively. In contrast, prazosin and tamsulosin showed little subtype selectivity.

Noradrenaline‐induced contractions of human lower urinary tract (LUT) tissues or rabbit bladder neck were competitively antagonized by Ro 70‐0004 (pA2 8.8 and 8.9), RS‐100329 (pA2 9.2 and 9.2), tamsulosin (pA2 10.4 and 9.8) and prazosin (pA2 8.7 and 8.3 respectively). Affinity estimates for tamsulosin and prazosin in antagonizing α1‐AR‐mediated contractions of human renal artery (HRA) and rat aorta (RA) were similar to those observed in LUT tissues, whereas Ro 70‐0004 and RS‐100329 were approximately 100 fold less potent (pA2 values of 6.8/6.8 and 7.3/7.9 in HRA/RA respectively).

The α1A‐AR subtype selectivity of Ro 70‐0004 and RS‐100329, demonstrated in both cloned and native systems, should allow for an evaluation of the clinical utility of a ‘uroselective’ agent for the treatment of symptoms associated with benign prostatic hyperplasia.

British Journal of Pharmacology (1999) 127, 252–258; doi:10.1038/sj.bjp.0702541
Effects of mitoxantrone on action potential and membrane currents in isolated cardiac myocytes
Authors: Wang Ge‐Xin , Zhou Xiao‐Bo , Eschenhagen Thomas , Korth Michael
Published: January 2005

The effects of mitoxantrone (MTO), an anticancer drug, on the membrane electrical properties of cardiac myocytes were investigated using the whole‐cell clamp technique.

In isolated guinea‐pig ventricular myocytes, 30 μM MTO induced a time‐dependent prolongation of action potential duration (APD) which was occasionally accompanied by early afterdepolarizations. APD prolongation was preserved in the presence of 10 μM tetrodotoxin and showed reverse rate‐dependence.

Both the inward rectifier K+ current (IK1) and the delayed rectifier K+ current (IK) of guinea‐pig ventricular myocytes were significantly depressed by 30 μM MTO. The rapidly activating component of IK (IKr) seemed to be preferentially blocked by MTO. The transient outward current was not affected by MTO in rat ventricular myocytes.

Thirty μM MTO had no direct effect on the L‐type Ca2+ current (ICa(L)), but reversed the inhibitory effect of 1 μM carbamylcholine but not the A1‐adenosine receptor agonist (−)‐N6‐phenylisopropyladenosine (1 μM) on ICa(L) enhanced by 50 nM isoprenaline in guinea‐pig ventricular myocytes. In guinea‐pig atrial mycotyes, 30 μM MTO inhibited by 93% the muscarinic receptor gated K+ current (IK,ACh) evoked by 1 μM carbamylcholine, whereas IK,ACh elicited by 100 μM GTPγS, a nonhydrolysable GTP analogue, was only decreased by 12%.

The specific binding of [3H]QNB, a muscarinic receptor ligand, to human atrial membranes was concentration‐dependently displaced by MTO (1–1000 μM).

In conclusion, MTO blocks cardiac muscarinic receptors and prolongs APD by inhibition of IK1 and IKr. The occasionally observed early afterdepolarizations may signify a potential cardiac hazard of the drug.

British Journal of Pharmacology (1999) 127, 321–330; doi:10.1038/sj.bjp.0702547
The attenuation of learning impairments induced after exposure to CO or trimethyltin in mice by sigma (σ) receptor ligands involves both σ1 and σ2 sites
Authors: Maurice Tangui , Phan Vân‐Ly , Noda Yukihiro , Yamada Kiyofumi , Privat Alain , Nabeshima Toshitaka
Published: January 2005

Sigma (σ) receptor ligands were previously reported to alleviate learning and memory impairments on several pharmacological and pathological rodent models of amnesia. Such effect was demonstrated as involving the σ1 subtype of σ receptor.

In this study, we characterized the pharmacological effect mediated by σ ligands on two lesional models of amnesia in mice: (1) the hypoxia‐related learning and memory impairment model induced by repeated exposure to carbon monoxide (CO) gas; and (2) the intoxication with trimethyltin (1 mg kg−1).

The selective σ1 ligand PRE‐084 (1 mg kg−1) or the non‐selective σ1/σ2 compounds DTG (0.1 mg kg−1), BD1008 (3 mg kg−1), and haloperidol (0.1 mg kg−1) reversed significantly the spontaneous alternation deficits observed 7 days after exposure to CO or 14 days after intoxication with trimethyltin.

The selective σ1 receptor antagonist NE‐100 (1 mg kg−1) was ineffective by itself, but blocked completely the PRE‐084 effects, partially the DTG effects, and did not affect the effects induced by BD1008 or haloperidol.

A similar pharmacological profile was observed in the step‐down type passive avoidance test performed 8 days after exposure to CO.

These results show that, in contrast to the previously reported amnesia models, the impairments induced after exposure to CO or intoxication with trimethyltin could be alleviated not only by σ1 receptor agonists but also by σ2 agonists. The particular pattern of neurodegeneration observed in these lesional models may explain these differences.

British Journal of Pharmacology (1999) 127, 335–342; doi:10.1038/sj.bjp.0702553
Parallel modulation of receptor for activated C kinase 1 and protein kinase C‐α and β isoforms in brains of morphine‐treated rats
Authors: Escribá Pablo V , García‐Sevilla Jesús A
Published: January 2005

Receptor for activated C kinase 1 (RACK1) is an intracellular receptor for protein kinase C (PKC) that regulates the cellular enzyme localization. Because opiate drugs modulate the levels of brain PKC (Ventayol et al., 1997), the aim of this study was to assess in parallel the effects of morphine on RACK1 and PKC‐α and β isozymes densities in rat brain frontal cortex by immunoblot assays.

Acute morphine (30 mg kg−1, i.p., 2 h) induced significant increases in the densities of RACK1 (33%), PKC‐α (35%) and PKC‐β (23%). In contrast, chronic morphine (10–100 mg kg−1, i.p., 5 days) induced a decrease in RACK1 levels (22%), paralleled by decreases in the levels of PKC‐α (16%) and PKC‐β (16%).

Spontaneous (48 h) and naloxone (2 mg kg−1, i.p., 2 h)‐precipitated morphine withdrawal after chronic morphine induced marked up‐regulations in the levels of RACK1 (38–41%), PKC‐α (51–52%) and PKC‐β (48–62%).

In the same brains and for all combined treatments, there were significant positive correlations between the density of RACK1 and those of PKC‐α (r=0.85, n=35) and PKC‐β (r=0.75, n=32).

These data indicate that RACK1 is involved in the short‐ and long‐term effects of morphine and in opiate withdrawal, and that RACK1 modulation by morphine or its withdrawal is parallel to those of PKC‐α and β isozymes. Since RACK1 facilitates the PKC substrate accessibility, driving its cellular localization, the coordinate regulation of the PKC/RACK system by morphine could be a relevant molecular mechanism in opiate addiction.

British Journal of Pharmacology (1999) 127, 343–348; doi:10.1038/sj.bjp.0702555
Endothelium is required in the vascular spasm induced by tetraethylammonium and endothelin‐1 in guinea‐pig aorta
Authors: Dorigo P , Maragno I , Santostasi G , Fraccarollo D
Published: January 2005

To investigate the role of endothelium in vascular spasm, we studied the influence of endothelin‐1 (ET‐1) on the contracting and spasmogenic effect of the K+‐channel blocker, tetraethylammonium (TEA), in aorta rings of reserpine‐treated guinea‐pigs, perfused with either control (5.5 mM) or elevated (50 mM) glucose concentration.

Endothelium‐dependent relaxation induced by acetylcholine was lost in rings contracted by noradrenaline in the presence of elevated glucose. In control medium, TEA (1–20 mM) induced a sustained tonic contraction, followed by a phasic spasm, characterized by rhythmic contractions. Elevated glucose, ET‐1 (3 nM), or both, reduced the EC50 of TEA‐induced tonic contraction, without modifying the maximum contractile effect.

In control medium, ET‐1 reduced the time before TEA‐induced spasm and increased the rate of rhythmic contractions. TEA‐induced spasm was abolished by elevated glucose, and restored by ET‐1. The spasm induced by TEA and ET‐1 was amplified by the ETA antagonist, EMD94246, and suppressed by the ETA‐ETB antagonist, bosentan. In endothelium‐denuded vessels incubated with high glucose and ET‐1, TEA evoked only a tonic contraction.

In control medium, L‐NAME (NG‐nitro‐L‐arginine methyl ester) abolished TEA‐induced rhythmic contractions. L‐arginine, but not D‐arginine, prevented the effect of L‐NAME. In the presence of elevated glucose and ET‐1, TEA‐induced spasm was not affected by L‐NAME, whereas verapamil, indomethacin, metyrapone, glybenclamide or apamin abolished the phasic spasm, unmasking the tonic contracture.

In conclusion, endothelium plays a regulatory role in the genesis and maintenance of TEA‐induced rhythmic contractions, through the release endothelium derived relaxing factor and vasodilating eicosanoids.

British Journal of Pharmacology (1999) 127, 505–513; doi:10.1038/sj.bjp.0702557
Cyclic AMP suppresses interleukin‐5 synthesis by human helper T cells via the downregulation of the calcium mobilization pathway
Authors: Kaminuma Osamu , Mori Akio , Ogawa Koji , Kikkawa Hideo , Nakata Aya , Ikezawa Katsuo , Okudaira Hirokazu
Published: January 2005

To delineate the mechanism by which cyclic AMP (cAMP) suppresses interleukin (IL)‐5 synthesis, the effects of prostaglandin (PG) E2, forskolin, dibutyryl (db)‐cAMP and the Ca2+ ionophore, ionomycin on cytokine synthesis, proliferation and CD25 expression of human T cells were investigated. Further studies were performed by measurement of the intracellular concentrations of cyclic AMP ([cAMP]i) and Ca2+ ([Ca2+]i) and by electrophoretic mobility shift analysis (EMSA).

PGE2, forskolin and db‐cAMP suppressed IL‐5 production by human T cell line following T cell receptor (TCR)‐stimulation. PGE2 suppressed TCR‐induced messenger RNA (mRNA) expression of IL‐2, IL‐4 and IL‐5, as well as proliferation and CD25 expression.

Cyclic AMP‐mediated suppression of cytokine synthesis, proliferation and CD25 expression in human T cells were attenuated by ionomycin.

[cAMP]i was increased by PGE2 and forskolin. PGE2 suppressed the TCR‐induced biphasic increase in [Ca2+]i. EMSA revealed that four specific protein‐DNA binding complexes related to NF‐AT were detected at the IL‐5 promoter sequence located from −119 to −90 relative to the transcription initiation site. The slowest migrating complex induced by TCR stimulation was enhanced by PGE2 and further upregulated by ionomycin. Another binding which did not compete with cold AP‐1 oligonucleotides, was constitutively present and was unaffected by PGE2 but enhanced by ionomycin.

The suppressive effect of cyclic AMP on human IL‐5 synthesis is mediated by interference with intracellular Ca2+ mobilization but distinct from the NF‐AT‐related pathway.

British Journal of Pharmacology (1999) 127, 521–529; doi:10.1038/sj.bjp.0702558