bluuebunny/crossref_metadata_2025_split huggingface dataset:
Voltage‐dependent block of normal and mutant muscle sodium channels by 4‐Chloro‐m‐Cresol
Authors: Haeseler G , Leuwer M , Kavan J , Würz A , Dengler R , Piepenbrock S 
Published: January 2005

The effects of 4‐Chloro‐m‐Cresol (4‐CmC) were examined on heterologously expressed wild type (WT), Paramyotonia Congenita (R1448H) and Hyperkalemic Periodic Paralysis (M1360V) mutant α‐subunits of human muscle sodium channels.
Block of rested sodium channels caused by 4‐CmC was concentration‐dependent with an ECR50 of 0.40 mM in WT, 0.45 mM in R1448H and 0.49 mM in M1360V.
Inactivation significantly promoted 4‐CmC‐induced sodium channel block in all clones indicated by 4‐CmC‐induced shifts of steady‐state availability curves, reflecting a higher proportion of channel block at depolarized membrane potentials. Channel block was almost complete (>90%) at concentrations close to the ECR50 (0.5 mM) on application of an inactivating prepulse before the test pulse.
4‐CmC accelerated the current decay following depolarization and prolonged recovery from inactivation in all clones. Of these, R1448H, the mutant which displayed severely impaired inactivation in the controls, responded to 4‐CmC with the most pronounced acceleration of inactivation. Control experiments revealed enhanced recovery from inactivation in the mutants, which was restored to normal in 0.1 mM 4‐CmC.
4‐CmC induced no additional frequency‐dependent block.
Our results clearly demonstrate that 4‐CmC is as effective as lidocaine (Fan et al., 1996) in blocking muscle sodium channels. Low concentrations of the compound (ECR50) were able to restore pathologically accelerated recovery from inactivation and impaired inactivation in the mutants to the WT value.

British Journal of Pharmacology (1999) 128, 1259–1267; doi:10.1038/sj.bjp.0702896
Nociceptin (1–7) antagonizes nociceptin‐induced hyperalgesia in mice
Authors: Sakurada Tsukasa , Sakurada Shinobu , Katsuyama Sou , Sakurada Chikai , Tan‐No Koichi , Terenius Lars 
Published: January 2005

Nociceptin and its N‐terminal fragment, nociceptin (1–7), were administered intrathecally (i.t.) into conscious mice. Nociceptin (3.0 fmol) produced a significant reduction in the nociceptive thermal threshold (hyperalgesia) measured as the tail‐flick and paw‐withdrawal responses. Nociceptin (1–7), injected i.t., at 150–1200 fmol had no significant effect. However, when nociceptin (1–7) (150–1200 fmol) was injected simultaneously with nociceptin (3.0 fmol), nociceptin‐induced hyperalgesia was significantly reduced. Analgesia induced by a high dose (1200 pmol) of nociceptin was not antagonized by co‐administration of nociceptin (1–7) (1200 fmol). These results suggest that N‐terminal fragments of nociceptin formed endogenously could modulate the hyperalgesic action of nociceptin in the spinal cord.British Journal of Pharmacology (1999) 128, 941–944; doi:10.1038/sj.bjp.0702898
Pharmacological similarities between native brain and heterologously expressed α4β2 nicotinic receptors
Authors: Shafaee Navid , Houng McCann , Truong Anthony , Viseshakul Nareerat , Figl Antonio , Sandhu Sumandeep , Forsayeth John R , Dwoskin Linda P , Crooks Peter A , Cohen Bruce N 
Published: January 2005

We studied the pharmacological properties of native rat brain and heterologously expressed rat α4β2 nicotinic receptors immunoprecipitated onto a fixed substrate with the anti‐α4 antibody mAb 299.
Immunodepletion with the anti‐β2 antibody mAb 270 showed that 89% of the mAb‐299‐precipitated rat brain receptors contained β2.
The association and dissociation rate constants for 30 pM ±[3H]‐epibatidine binding to α4β2 receptors expressed in oocytes were 0.02±0.01 and 0.03±0.01 min−1 (±standard error, degrees of freedom=7–8) at 20–23°C.
The Hill coefficients for ±[3H]epibatidine binding to the native brain, α4β2 receptors expressed in oocytes, and α4β2 receptors expressed in CV‐1 cells (using recombinant adenovirus) were 0.69–0.70 suggesting a heterogeneous receptor population. Fits of the ±[3H]‐epibatidine concentration‐binding data to a two‐site model gave KD s of 8–30 and 560–1,200 pM. The high‐affinity sites comprised 73–74% of the native brain and oocyte α4β2 receptor population, 85% of the CV‐1 α4β2 receptor population.
The expression of rat α4β2 receptors in CV‐1 cells using vaccinia viral infection‐transfection resulted in a more homogeneous receptor population (Hill coefficient of 1.0±0.2). Fits of the ±[3H]‐epibatidine binding data to a single‐site model gave a KD of 40±3 pM.
DHβE (IC50=260–470 nM) and the novel nicotine analogue NDNI (IC50=7–10 μM) inhibited 30 pM±[3H]‐epibatidine binding to the native brain and heterologously expressed α4β2 receptors equally well.
The results show that α4β2‐containing nicotinic receptors in the rat brain and heterologously expressed rat α4β2 receptors have similar affinities for ±[3H]‐epibatidine, DHβE, and NDNI.

British Journal of Pharmacology (1999) 128, 1291–1299; doi:10.1038/sj.bjp.0702900
Efficient functional coupling of the human D3 dopamine receptor to Go subtype of G proteins in SH‐SY5Y cells
Authors: Zaworski Phillip G , Alberts Glen L , Pregenzer Jeffrey F , Im Wha Bin , Slightom Jerry L , Gill Gurnam S 
Published: January 2005

The D3 dopamine receptor presumably activates Gi/Go subtypes of G‐proteins, like the structurally analogous D2 receptor, but its signalling targets have not been clearly established due to weak functional signals from cloned receptors as heterologously expressed in mostly non‐neuronal cell lines.
In this study, recombinant human D3 receptors expressed in a human neuroblastoma cell line, SH‐SY5Y, produced much greater signals than those expressed in a human embryonic kidney cell line, HEK293. Quinpirole, a prototypic agonist, markedly inhibited forskolin‐stimulated cyclic AMP production and Ca2+‐channel (N‐type) currents in SH‐SY5Y cells, and enhanced GTPγ35S binding in isolated membranes, nearly ten times greater than that observed in HEK293 cell membranes.
GTPγ35S‐bound Gα subunits from quinpirole‐activated and solubilized membranes were monitored upon immobilization with various Gα‐specific antibodies. Gαo subunits (not Gαi) were highly labelled with GTPγ35S in SH‐SY5Y, but not in HEK293 cell membranes, despite their abundance in the both cell types, as shown with reverse transcription‐polymerase chain reaction and Western blots. N‐type Ca2+ channels and adenylyl cyclase V (D3‐specific effector), on the other hand, exist only in SH‐SY5Y cells.
More efficient coupling of the D3 receptor to Go subtypes in SH‐SY5Y than HEK293 cells may be attributed, at least in part, to the two D3 neuronal effectors only present in SH‐SY5Y cells (N‐type Ca2+‐channels and adenylyl cyclase V). The abundance of Go subtypes in the both cell lines seems to indicate their availability not a limiting factor.

British Journal of Pharmacology (1999) 128, 1181–1188; doi:10.1038/sj.bjp.0702905
Roles of atypical protein kinase C in lysophosphatidic acid‐induced type II adenylyl cyclase activation in RAW 264.7 macrophages
Authors: Lin Wan‐Wan , Chang Sheng‐Ho , Wang Seu‐Mei 
Published: January 2005

Lysophosphatidic acid (LPA) has been widely studied as a naturally occurring and multifunctional phospholipid messenger in diverse tissue and cell types and shown to inhibit adenylyl cyclase (AC) by a G protein‐mediated mechanism.
In type II AC‐expressing mouse RAW 264.7 macrophages, we showed that LPA at 3–50 μM increased cyclic AMP formation in a concentration‐dependent manner, the effect being additive with that of forskolin or cholera toxin, and synergistic with that of prostaglandin E1 (PGE1) or isoproterenol.
The potentiation effect of LPA was unaffected by the removal of serum or pertussis toxin treatment.
Both colchicine and cytochalasin B potentiated the cyclic AMP response to PGE1, the effect being additive to that of LPA.
On studying the regulation of type II AC by protein kinase C (PKC), phorbol 12‐myristate‐13 acetate (PMA) potentiated the PGE1‐elicited cyclic AMP response, this effect being non‐additive to that of LPA, suggesting that PKC activation was the common mechanism involved in AC potentiation by LPA and PMA.
PKC inhibitor Ro 31‐8220, but not Go 6976, significantly inhibited the LPA‐induced cyclic AMP potentiation.
The potentiation effect of LPA was unaffected by long‐term treatment with PMA, which resulted in the down‐regulation of PKCα, βI, βII and PKCδ, but not PKCε, μ, λ and ζ.
By in situ kinase assay, we found a marked increase in atypical PKC activity after LPA treatment.
Taken together, we conclude that LPA can elicit a unique signalling cascade in RAW 264.7 macrophages and increase type II AC activity via the activation of atypical PKC.

British Journal of Pharmacology (1999) 128, 1189–1198; doi:10.1038/sj.bjp.0702906
Identification of the G‐protein‐coupled ORL1 receptor in the mouse spinal cord by [35S]‐GTPγS binding and immunohistochemistry
Authors: Narita Minoru , Mizoguchi Hirokazu , Oji David E , Narita Michiko , Dun Nae J , Hwang Bang H , Nagase Hiroshi , Tseng Leon F 
Published: January 2005

Although the ORL1 receptor is clearly located within the spinal cord, the functional signalling mechanism of the ORL1 receptor in the spinal cord has not been clearly documented. The present study was then to investigate the guanine nucleotide binding protein (G‐protein) activation mediated through by the ORL1 receptor in the mouse spinal cord, measuring the modulation of guanosine‐5′‐o‐(3‐[35S]‐thio) triphosphate ([35S]‐GTPγS) binding by the putative endogenous ligand nociceptin, also referred as orphanin FQ. We also studied the anatomical distribution of nociceptin‐like immunoreactivity and nociceptin‐stimulated [35S]‐GTPγS autoradiography in the spinal cord.
Immunohistochemical staining of mouse spinal cord sections revealed a dense plexus of nociceptin‐like immunoreactive fibres in the superficial layers of the dorsal horn throughout the entire length of the spinal cord. In addition, networks of fibres were seen projecting from the lateral border of the dorsal horn to the lateral grey matter and around the central canal.
In vitro [35S]‐GTPγS autoradiography showed high levels of nociceptin‐stimulated [35S]‐GTPγS binding in the superficial layers of the mouse dorsal horn and around the central canal, corresponding to the areas where nociceptin‐like immunoreactive fibres were concentrated.
In [35S]‐GTPγS membrane assay, nociceptin increased [35S]‐GTPγS binding of mouse spinal cord membranes in a concentration‐dependent and saturable manner, affording maximal stimulation of 64.1±2.4%. This effect was markedly inhibited by the specific ORL1 receptor antagonist [Phe1Ψ (CH2‐NH) Gly2] nociceptin (1–13) NH2. None of the μ‐, δ‐, and κ‐opioid and other G‐protein‐coupled receptor antagonists had a significant effect on basal or nociceptin‐stimulated [35S]‐GTPγS binding.
These findings suggest that nociceptin‐containing fibres terminate in the superficial layers of the dorsal horn and the central canal and that nociceptin released in these areas may selectively stimulate the ORL1 receptor to activate G‐protein. Furthermore, the unique pattern of G‐protein activation in the present study provide additional evidence that nociceptin is distinct from the μ‐, δ‐ or κ‐opioid system.

British Journal of Pharmacology (1999) 128, 1300–1306; doi:10.1038/sj.bjp.0702907
Characterization of the in vitro effects of 5‐hydroxytryptamine (5‐HT) on identified neurones of the rat dorsal motor nucleus of the vagus (DMV)
Authors: Browning Kirsteen N , Travagli R Alberto 
Published: January 2005

Whole cell patch clamp techniques were used on thin brainstem slices to investigate the effects of 5‐hydroxytryptamine (5‐HT) on gastrointestinal‐projecting dorsal motor nucleus of the vagus (DMV) neurones. Neurones were identified as projecting to the stomach (n=122) or intestine (n=84) if they contained the fluorescent tracer Dil after it had been applied to the gastric fundus, corpus or antrum/pylorus or to the duodenum or caecum.
A higher proportion of intestinal neurones (69%) than gastric neurones (47%) responded to 5‐HT with a concentration‐dependent inward current which was antagonized fully by the 5‐HT2A receptor antagonist ketanserin (1 μM).
Stimulation of the nucleus tractus solitarius (NTS) induced inhibitory synaptic currents that were reduced in amplitude by application of the 5‐HT1A receptor agonist 8‐OHDPAT (1 μM) or the 5‐HT1A/1B receptor agonist TFMPP (1 μM) in 61% and 52% of gastric‐ and intestinal‐projecting neurones, respectively. 5‐HT also significantly reduced the frequency but not the amplitude of spontaneous inhibitory currents.
These data show that 5‐HT excites directly a larger proportion of intestinal projecting neurones than gastric‐projecting neurones, as well as inhibiting synaptic transmission from the NTS to the DMV. These data imply that the response to DMV neurones to 5‐HT may be determined and classified by their specific projections.

British Journal of Pharmacology (1999) 128, 1307–1315; doi:10.1038/sj.bjp.0702908
Effect of the nonpeptide neurotrophic compound SR 57746A on the phenotypic survival of purified mouse motoneurons
Authors: Duong F H T , Warter J M , Poindron P , Passilly P 
Published: January 2005

Neurotrophic factors have been used for the treatment of several neurodegenerative diseases. However, their use is limited by their inability to cross the blood‐brain barrier, their short half life and their side effects. SR 57746A is a new orally active compound that exhibits in vivo and in vitro neurotrophic effects in several experimental models.
We show here that SR 57746A (1 μM) increases the phenotypic survival of embryonic purified mouse motoneurons in vitro to the same extent as brain‐derived neurotrophic factor (100 ng ml−1), and increases the outgrowth and number of their neurites. It acts in a dose‐dependent manner up to 1 μM which is the optimal concentration. Above this concentration, its neurotrophic effect decreases.
Genistein (10 μM), a protein tyrosine kinase inhibitor, also increases the phenotypic survival and differentiation of mouse motoneurons. It does not act in a synergistic or additive manner with SR 57746A. However, at concentrations equal or superior to 25 μM, it decreases the survival of motoneurons. This suggests that the neurotrophic effect of genistein is due to a favourable alteration of equilibrium between phosphorylated and dephosphorylated states of proteins involved in survival and differentiation of motoneurons.
Like genistein, SR 57746A should be used at a critical concentration (1 μM) to exert its optimal effects. Since SR 57746A does not act synergistically with genistein, it is likely that its mechanism of action involves a pathway similar to that affected by this tyrosine kinase inhibitor.
At the present time, SR 57746A is the only orally active compound and the only synthetic compound shown to be active on motoneurons in vitro. It should thus be considered as a good candidate for the treatment of motoneuron diseases.

British Journal of Pharmacology (1999) 128, 1385–1392; doi:10.1038/sj.bjp.0702910
Investigation of the subtypes of α1‐adrenoceptor mediating contractions of rat vas deferens
Authors: Honner Valerie , Docherty J R 
Published: January 2005

The subtypes of α1‐adrenoceptor mediating contractions of rat vas deferens to endogenous and exogenous noradrenaline and to the exogenous agonists methoxamine, phenylephrine and A61603 have been examined.
The effects of antagonists on the shape of concentration‐response curves, both tonic and phasic, to the four agonists were analysed. Prazosin produced parallel shifts in all cases. Particularly for RS 17053 against noradrenaline, there was some evidence for a resistant component of the agonist response. High concentrations of RS 17053 (1–10 μM) virtually abolished tonic contractions but phasic contractions were resistant.
A series of nine antagonists (the above and WB4101, benoxathian, phentolamine, BMY 7378, HV 723, spiperone) were investigated against contractions to noradrenaline. The correlation with the potency of the series of α1‐adrenoceptor antagonists against contractions to noradrenaline was significant only for the α1A‐adrenoceptor ligand binding site (r=0.88, n=9, P<0.01).
In epididymal portions (nifedipine 10 μM), the isometric contraction to a single electrical pulse is α1‐adrenoceptor mediated. The correlation with ligand binding sites for 11 antagonists (the above plus ARC 239 and (+)‐niguldipine) was significant only for the α1D‐adrenoceptor subtype (r=0.65, n=11, P<0.05).
In conclusion, tonic contractions of rat vas deferens produced by exogenous agonists are mediated predominantly by α1A‐adrenoceptors, although a second subtype of receptor may additionally be involved in phasic contractions. Nerve‐stimulation evoked α1‐adrenoceptor mediated contractions seem to predominantly involve non‐α1A‐adrenoceptors, and the receptor involved resembles the α1D‐receptor.

British Journal of Pharmacology (1999) 128, 1323–1331; doi:10.1038/sj.bjp.0702913
Perindopril, an angiotensin converting enzyme inhibitor, in pulmonary hypertensive rats: comparative effects on pulmonary vascular structure and function
Authors: Jeffery Trina K , Wanstall Janet C 
Published: January 2005

Hypoxic pulmonary hypertension in rats (10% O2, 4 weeks) is characterized by changes in pulmonary vascular structure and function. The effects of the angiotensin converting enzyme inhibitor perindopril (oral gavage, once daily for the 4 weeks of hypoxia) on these changes were examined.
Perindopril (30 mg kg−1 d−1) caused an 18% reduction in pulmonary artery pressure in hypoxic rats.
Structural changes (remodelling) in hypoxic rats included increases in (i) critical closing pressure in isolated perfused lungs (remodelling of arteries <50 μm o.d.) and (ii) medial wall thickness of intralobar pulmonary arteries, assessed histologically (vessels 30–100 and 101–500 μm o.d.). Perindopril 10 and 30 mg kg−1 d−1 attenuated remodelling in vessels 100 μm (lungs and histology), 30 mg kg−1 d−1 was effective in vessels 101–500 μm but neither dose prevented hypertrophy of main pulmonary artery. 3 mg kg−1 d−1 was without effect.
Perindopril (30 mg kg−1 d−1) prevented the exaggerated hypoxic pulmonary vasoconstrictor response seen in perfused lungs from hypoxic rats but did not prevent any of the functional changes (i.e. the increased contractions to 5‐HT, U46619 (thromboxane‐mimetic) and K+ and diminished contractions to angiotensins I and II) seen in isolated intralobar or main pulmonary arteries. Acetylcholine responses were unaltered in hypoxic rats.
We conclude that, in hypoxic rats, altered pulmonary vascular function is largely independent of remodelling. Hence any drug that affects only remodelling is unlikely to restore pulmonary vascular function to normal and, like perindopril, may have only a modest effect on pulmonary artery pressure.

British Journal of Pharmacology (1999) 128, 1407–1418; doi:10.1038/sj.bjp.0702923
Studies on the acute and chronic effects of reboxetine on extracellular noradrenaline and other monoamines in the rat brain
Authors: Sacchetti G , Bernini M , Bianchetti A , Parini S , Invernizzi R W , Samanin R 
Published: January 2005

The effect of reboxetine, a novel antidepressant drug that potently and selectively inhibits neuronal noradrenaline (NA) uptake, on brain extracellular monoamines was studied by microdialysis.
Fifteen mg kg−1 i.p. reboxetine raised extracellular NA in the frontal cortex (by 242%) and dorsal hippocampus (by 240%).
Idazoxan (1 mg kg−1 s.c.), given 60 min after 15 mg kg−1 reboxetine, markedly potentiated the effect on extracellular NA in the frontal cortex (by 1580%) and dorsal hippocampus (by 1360%), but had no effect by itself.
Twenty‐four hours after the last injection of a chronic schedule (15 mg kg−1 i.p. once daily for 14 days) reboxetine had no effect on basal extracellular concentrations of NA in the dorsal hippocampus and a challenge dose of reboxetine (15 mg kg−1) raised extracellular NA similarly in rats treated chronically with reboxetine (by 353%) and saline (by 425%).
Ten and 20 μg kg−1 i.p. clonidine dose‐dependently reduced hippocampal extracellular NA similarly in rats given chronic reboxetine (by 32% and 57%) and saline (by 42% and 56%).
Extracellular concentrations of dopamine and 5‐HT in the striatum were similar in rats treated chronically with reboxetine and saline. A challenge dose of reboxetine (15 mg kg−1) had no effect on striatal extracellular dopamine and slightly increased striatal extracellular 5‐HT to a similar extent in rats treated chronically with reboxetine (by 137%) and saline (by 142%).
The results suggest that combining reboxetine with an α2‐adrenoceptor antagonist may facilitate its antidepressant activity. Repeated treatment confirmed that reboxetine is fairly selective for the noradrenergic system but provided no evidence of adaptive changes in that system that could facilitate its effect on extracellular NA.

British Journal of Pharmacology (1999) 128, 1332–1338; doi:10.1038/sj.bjp.0702926
Direct myocardial anti‐ischaemic effect of GTN in both nitrate‐tolerant and nontolerant rats: a cyclic GMP‐independent activation of KATP
Authors: Csont Tamás , Szilvássy Zoltán , Fülöp Ferenc , Nedeianu Saviana , Páli Tibor , Tosaki Árpád , Dux László , Ferdinandy Péter 
Published: January 2005

We have recently demonstrated that glyceryl trinitrate (GTN) exerts a direct myocardial anti‐ischaemic effect in both GTN‐tolerant and nontolerant rats. Here we examined if this effect is mediated by GTN‐derived nitric oxide (NO) and involves guanosine 3′5′ cyclic monophosphate (cyclic GMP) and ATP‐sensitive K+ channels (KATP).
Rats were treated with 100 mg kg−1 GTN or vehicle s.c. three times a day for 3 days to induce vascular GTN‐tolerance or nontolerance. Isolated working hearts obtained from either GTN‐tolerant or nontolerant rats were subjected to 10 min coronary occlusion in the presence of 10−7 M GTN or its solvent.
GTN improved myocardial function and reduced lactate dehydrogenase (LDH) release during coronary occlusion in both GTN‐tolerant and nontolerant hearts.
Cardiac NO content significantly increased after GTN administration in both GTN‐tolerant and nontolerant hearts as assessed by electron spin resonance. However, cardiac cyclic GMP content measured by radioimmunoassay was not changed by GTN administration.
When hearts from both GTN‐tolerant and nontolerant rats were subjected to coronary occlusion in the presence of the KATP‐blocker glibenclamide (10−7 M), the drug itself did not affect myocardial function and LDH release, however, it abolished the anti‐ischaemic effect of GTN.
We conclude that GTN opens KATP via a cyclic GMP‐independent mechanism, thereby leading to an anti‐ischaemic effect in the heart in both GTN‐tolerant and nontolerant rats.

British Journal of Pharmacology (1999) 128, 1427–1434; doi:10.1038/sj.bjp.0702929