bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pharmacological evidence for CGRP uptake into perivascular capsaicin sensitive nerve terminals
Authors: Sams‐Nielsen Anette , Orskov Cathrine , Jansen‐Olesen Inger 
Published: January 2005

Specific mechanisms, providing reuptake of cathecholamine and amino acid neurotransmitters (e.g. serotonin and glutamate) into cells of the central nervous system are well known, whereas neuronal uptake of neuropeptide transmitters have not previously been reported.
In the present study we present evidence for uptake of the 37 amino acid neuropeptide, calcitonin gene‐related peptide (CGRP) into perivascular terminals of capsaicin sensitive nerve fibres, innervating the guinea‐pig basilar artery.
Release of CGRP from perivascular nerve terminals was obtained by capsaicin‐induced vanilloid receptor‐stimulation and detected as CGRP receptor‐mediated dilation of isolated segments of the guinea‐pig basilar artery.
Following three repeated capsaicin challenges, CGRP‐depleted segments were incubated with CGRP. This caused significant reappearance of capsaicin‐induced vasodilatory responses. These responses were dependent on duration and concentration of the preceding CGRP incubation and were inhibited by the CGRP receptor antagonist, CGRP8–37.
The CGRP‐re‐depletion was significantly reduced when CGRP8–37 was present during the preceding CGRP incubation. Thus, presynaptic CGRP receptors are likely to be involved in neuronal CGRP uptake.
Incubating the artery segments with 125I‐CGRP allowed subsequent detection of capsaicin‐induced 125I‐release.
Immunohistochemical experiments showed that only terminal CGRP is subject to capsaicin‐induced depletion in vitro, whereas CGRP‐immunoreactivity endures in the nerve fibres.

British Journal of Pharmacology (2001) 132, 1145–1153; doi:10.1038/sj.bjp.0703910
Involvement of cyclic AMP systems in morphine physical dependence in mice: prevention of development of morphine dependence by rolipram, a phosphodiesterase 4 inhibitor
Authors: Mamiya Takayoshi , Noda Yukihiro , Ren Xiuhai , Hamdy Moustafa , Furukawa Shoei , Kameyama Tsutomu , Yamada Kiyofumi , Nabeshima Toshitaka 
Published: January 2005

In this study, we examined whether morphine dependence was inhibited by rolipram, a cyclic AMP selective phosphodiesterase inhibitor in mice, since a role for the cyclic AMP systems in the development of morphine dependence has been reported.
Mice, which received morphine (10 mg kg−1 s.c.) twice a day for 5 days showed withdrawal syndromes such as jumping, rearing and forepaw tremor following naloxone challenge (5 mg kg−1 i.p.) on the 6th day.
Such mice exhibited a significant elevation of cyclic AMP levels in the thalamus compared to control mice. However, co‐administration of rolipram (1 mg kg−1 i.p.) with morphine for 5 days significantly attenuated the severity of the withdrawal syndrome and the increase in the cyclic AMP levels after the administration of naloxone.
In naïve mice, acute morphine treatment (10 mg kg−1 s.c.) decreased cyclic AMP levels in the thalamus and cerebral cortex 10 min later. The decrease of cyclic AMP levels induced by acute morphine treatment was blocked by co‐administration of rolipram (1 mg kg−1 i.p.). However, acute rolipram did not affect the naloxone‐precipitated morphine withdrawal syndrome.
These results suggest that the elevation of the cyclic AMP levels is involved in the development of morphine withdrawal syndrome and that blockade of the morphine‐induced reduction of cyclic AMP levels by chronic rolipram inhibits the development of dependence and the behavioural and biochemical changes induced by naloxone. Furthermore, rolipram may be a useful drug for attenuating the development of morphine dependence.

British Journal of Pharmacology (2001) 132, 1111–1117; doi:10.1038/sj.bjp.0703912
The transport activity of the human cationic amino acid transporter hCAT‐1 is downregulated by activation of protein kinase C
Authors: Gräf Petra , Förstermann Ulrich , Closs Ellen I 
Published: January 2005

The human cationic amino acid transporter hCAT‐1 contains several consensus sequences for phosphorylation by protein kinase C (PKC). This study investigates the effect of PKC activation on hCAT‐1‐mediated transport.
When expressed in Xenopus laevis oocytes, hCAT‐1‐mediated L‐arginine transport was reduced to 44±3% after a 30 min treatment of the oocytes with 100 nM phorbol‐12‐myristate‐13‐acetate (PMA). 4α‐phorbol‐12,13‐didecanoate (4α‐PDD, 100 nM) had no effect.
In EA.hy926 endothelial cells, maximal inhibition of hCAT‐1‐mediated L‐arginine transport (to 3 – 11% of control) was observed after treatment of the cells with 100 nM PMA for 4 h. A 20 – 30 h exposure of the cells to 100 nM PMA led to the recovery of the L‐arginine uptake rate that was now resistant to a second application of PMA. Phorbol‐12,13‐dibutyrate had similar effects as PMA, whereas 4α‐PDD had no effect. One μM bisindolylmaleimide I reduced the PMA effect significantly.
Interestingly, a 4 h treatment with 100 nM PMA increased the expression of hCAT‐1 mRNA 3 – 5 fold. hCAT‐1 protein levels were unchanged for up to 4 h after PMA treatment and then increased slightly between 8 – 28 h.
It is concluded that PMA downregulates the intrinsic activity of hCAT‐1 by a pathway involving protein kinase C.

British Journal of Pharmacology (2001) 132, 1193–1200; doi:10.1038/sj.bjp.0703921
Pharmacological analysis of cannabinoid receptor activity in the rat vas deferens
Authors: Christopoulos Arthur , Coles Peter , Lay Lucy , Lew Michael J , Angus James A 
Published: January 2005

The interaction between the cannabinoid agonists, WIN 55,212‐2 or CP 55,940 with the CB1 receptor‐selective antagonists, SR141716A or LY320135 was investigated using the rat electrically‐stimulated vas deferens bioassay.
Tissues were stimulated by single‐field pulses (150 V, 0.5 ms) delivered every 30 mins. In the presence of nifedipine (3 μM), agonists elicited a concentration‐dependent inhibition of the contractile response, with pEC50 values of 7.93 and 6.84 for WIN 55,212‐2 and CP 55,940, respectively.
SR141716A and LY320135 caused parallel dextral displacements of the agonist concentration‐response curves. However, the shift of the agonist curves by either antagonist was accompanied by a concentration‐dependent enhancement of basal (agonist‐independent) tissue contraction.
Addition of the amidase inhibitor, phenylmethylsulphonylfluoride (200 μM), resulted in a significant reduction of the basal twitch response, an effect consistent with the presence of tonic receptor activation mediated by the endogenous cannabinoid, anandamide.
In light of these findings, we propose a theoretical model of competitive agonist‐antagonist interaction in the presence of endogenous agonist tone that was used to derive an optimized analytical approach for the determination of antagonist potency estimates under conditions of tonic receptor activation.
This approach yielded pKB estimates for SR141716A and LY320135 that were in good agreement with their activity at cannabinoid CB1 receptors.
It is concluded that the rat vas deferens contains prejunctional cannabinoid CB1 receptors that are under tonic activation from endogenous substances; under these conditions our analytical approach is preferable to the standard methods for the determination of antagonist potency.

British Journal of Pharmacology (2001) 132, 1281–1291; doi:10.1038/sj.bjp.0703930
Dual effects of muscarinic M2 acetylcholine receptors on the synthesis of cyclic AMP in CHO cells: dependence on time, receptor density and receptor agonists
Authors: Michal Pavel , Lysíková Michaela , Tuček Stanislav 
Published: January 2005

Muscarinic M2 receptors normally inhibit the production of cyclic AMP via Gi proteins, but a stimulatory component occurs in their effect at high agonist concentrations, believed to be based on the activation of Gs proteins. We investigated the conditions which determine the occurrence and extent of the stimulatory component in CHO cells stably expressing muscarinic M2 receptors.
Biphasic concentration‐response curves (decline followed by return towards control values) were obtained after 10 min incubation with carbachol, oxotremorine‐M, acetylcholine, arecoline and arecaidine propargyl ester, but the upward phase was missing with oxotremorine, methylfurmethide, furmethide and pentylthio‐TZTP. Shortening the incubation favoured the occurrence of the stimulatory component. Carbachol (1 mM) and oxotremorine‐M (1 mM) brought about net stimulation (above 100% of control) of cyclic AMP synthesis during 2 min incubations. The stimulatory components disappeared after the density of receptors had been lowered with oxyphenonium mustard.
All agonists stimulated the synthesis of cyclic AMP in cells pretreated with pertussis toxin.
Most differences between agonists regarding the stimulatory component of their effect on cyclic AMP synthesis could be explained by differences in their efficacy and the induced receptor internalization.
We propose that the Gs‐mediated stimulatory component of the effect of muscarinic M2 receptors on cyclic AMP synthesis only occurs if the density of activated receptors is high enough to saturate the Gi proteins and proportionate to the receptors' low affinity for the Gs proteins. It tends to be abolished by receptor internalization.

British Journal of Pharmacology (2001) 132, 1217–1228; doi:10.1038/sj.bjp.0703931
Tonabersat (SB‐220453) a novel benzopyran with anticonvulsant properties attenuates trigeminal nerve‐induced neurovascular reflexes
Authors: Parsons Andrew A , Bingham Sharon , Raval Pravin , Read Simon , Thompson Mervyn , Upton Neil 
Published: January 2005

The effects of tonabersat (SB‐220453) were evaluated on trigeminal nerve ganglion stimulation‐induced sensory‐autonomic neurovascular reflexes in the anaesthetized cat. Comparisons were made to intravenous administration of carabersat (SB‐204269), and to valproate, gabapentin and lamotrigine following intraduodenal administration.
There were no effects on resting blood pressure, heart rate, carotid blood flow or carotid vascular resistance for any compound evaluated.
Trigeminal nerve ganglion stimulation increased carotid blood flow by 65% and reduced vascular resistance by 41% with minimal effect on blood pressure (<10%) and no effect on heart rate. Intravenous infusion of tonabersat or carabersat (both 3.4 μmol h−1) produced time related reductions in stimulation‐induced responses with a maximal inhibition (relative to control) of 30±7% (n=4), at 240 min for tonabersat and 33±4% (n=3) at 180 min for carabersat. Tonabersat (11.5 μmol h−1) produced a similar inhibitory effect (32±9%, n=4) after 120 min of infusion.
Following intraduodenal administration of tonabersat, the maximal inhibition of nerve stimulation‐induced responses was 55±4% at 120 min (n=4) for tonabersat 10 mg kg−1, and 24±2% after 180 min for 1 mg kg−1 (n=4).
Intraduodenal administration of sodium valproate (10 or 100 mg kg−1 n=4/group) had no effect on neurovascular reflexes. Maximal inhibition of nerve ganglion‐stimulated reductions in carotid vascular resistance were observed at 150 min for lamotrigine (50 mg kg−1, 52±12%, n=4) and gabapentin (100 mg kg−1, 17±13%, n=3). Lamotrigine 10 mg kg−1 produced 22±11% (n=3) inhibition after 180 min.
These data demonstrate blockade of trigeminal parasympathetic reflexes with tonabersat, carabersat and other anticonvulsants. These agents may therefore have therapeutic benefit in conditions where this type of reflex is evident.

British Journal of Pharmacology (2001) 132, 1549–1557; doi:10.1038/sj.bjp.0703932
Effects of some sterically hindered phenols on whole‐cell Ca2+current of guinea‐pig gastric fundus smooth muscle cells
Authors: Fusi Fabio , Saponara Simona , Gagov Hristo , Sgaragli Giampietro 
Published: January 2005

The aim of the present study was to investigate the effects of extracellular application of some sterically‐hindered phenols, namely 3‐t‐butyl‐4‐hydroxyanisole (BHA), 3,5‐di‐t‐butyl‐4‐hydroxyanisole (DTBHA) and the dimer of BHA, 2,2′‐dihydroxy‐3,3′‐di‐t‐butyl‐5,5′‐dimethoxydiphenyl (DIBHA), on the whole‐cell Ca2+current (ICa) of freshly isolated smooth muscle cells from the guinea‐pig gastric fundus, in the presence of a range of Ca2+concentrations (1 – 5 mM) using the patch‐clamp technique. The influx of Ca2+had characteristics of L‐typeICa(ICa(L)).BHA as well as DTBHA inhibitedICa(L)in a concentration‐dependent manner, during depolarization to 10 mV from a holding potential of −50 mV. Bath application of BHA (50 μM) and DTBHA (30 μM) decreasedICa(L)by 48.9% and 45.2%, respectively. This inhibition was only partially reversible. In contrast, DIBHA (up to 50 μM) was devoided of effects onICa(L).BHA inhibition ofICa(L)was voltage‐dependent and inversely related to the external concentration of Ca2+. On the other hand, DTBHA inhibition was only voltage‐dependent.BHA and DTBHA shifted the voltage range of the steady‐state inactivation curve to more negative potentials by 8 mV at the mid‐potential of the curve, without affecting the activation curve. Furthermore, BHA and DTBHA did not modify the time‐course of the current decay.We conclude that the inhibition ofICa(L)by BHA and DTBHA is qualitatively similar to that of a Ca2+channel blocker and is characterized by the stabilizing effect of the inactivated state of the channel.British Journal of Pharmacology(2001)132, 1326–1332; doi:10.1038/sj.bjp.0703935
Inhibition of the cyclin D1/E2F pathway by PCA‐4230, a potent repressor of cellular proliferation
Authors: Goukassian David , Sanz‐González Silvia M , Pérez‐Roger Ignacio , Font de Mora Jaime , Ureña Jesús , Andrés Vicente 
Published: January 2005

Tight control of cellular growth is essential to ensure normal tissue patterning and prevent pathological responses. Excessive vascular smooth muscle cell (VSMC) proliferation is associated with the pathophysiology of atherosclerosis and restenosis post‐angioplasty. Thus, drug targeting of pathological VSMC growth may be a suitable therapeutic intervention in vascular proliferative diseases.
In the present study, we investigated the mechanisms underlying VSMC growth arrest induced by the pharmacological agent PCA‐4230. Addition of PCA‐4230 to cultured VSMCs blocked the induction of cyclin D1 and cyclin A expression normally seen in serum‐restimulated cells. Moreover, PCA‐4230 inhibited cyclin‐dependent kinase 2 (CDK2) activity and abrogated hyperphosphorylation of the retinoblastoma (Rb) gene product. Similarly, PCA‐4230‐dependent growth arrest of transformed cell lines correlated with reduced level of cyclin D1 protein and inhibition of CDK2 activity. Consistent with these findings, PCA‐4230 repressed serum‐inducible cyclin A promoter activity, and overexpression of either cyclin D1 or E2F1 efficiently circumvented this inhibitory effect. Importantly, adenovirus‐mediated overexpression of E2F1 restored S‐phase entry in PCA‐4230‐treated VSMCs, demonstrating that PCA‐4230 represses cyclin A gene expression and VSMC growth via inhibition of the cyclin D1/E2F pathway.
Because of its ability to inhibit the growth of human VSMCs and transformed cell lines, future studies are warranted to assess whether PCA‐4230 may be a suitable therapeutic intervention for the treatment of hyperproliferative disorders, including cardiovascular disease and cancer.

British Journal of Pharmacology (2001) 132, 1597–1605; doi:10.1038/sj.bjp.0703945
Cyclo‐oxygenase and lipoxygenase pathways in mast cell dependent‐neurogenic inflammation induced by electrical stimulation of the rat saphenous nerve
Authors: Le Filliatre G , Sayah S , Latournerie V , Renaud J F , Finet M , Hanf R 
Published: January 2005

We investigated the role of arachidonic acid metabolism and assessed the participation of mast cells and leukocytes in neurogenic inflammation in rat paw skin. We compared the effect of lipoxygenase (LOX) and cyclo‐oxygenase (COX) inhibitors on oedema induced by saphenous nerve stimulation, substance P (SP), and compound 48/80.
Intravenous (i.v.) pre‐treatment with a dual COX/LOX inhibitor (RWJ 63556), a dual LOX inhibitor/cysteinyl‐leukotriene (CysLt) receptor antagonist (Rev 5901), a LOX inhibitor (AA 861), a five‐lipoxygenase activating factor (FLAP) inhibitor (MK 886), or a glutathione S‐transferase inhibitor (ethacrynic acid) significantly inhibited (40 to 60%) the development of neurogenic oedema, but did not affect cutaneous blood flow. Intradermal (i.d.) injection of LOX inhibitors reduced SP‐induced oedema (up to 50% for RWJ 63556 and MK 886), whereas ethacrynic acid had a potentiating effect.
Indomethacin and rofecoxib, a highly selective COX‐2 inhibitor, did not affect neurogenic and SP‐induced oedema. Surprisingly, the structurally related COX‐2 inhibitors, NS 398 and nimesulide, significantly reduced both neurogenic and SP‐induced oedema (70% and 42% for neurogenic oedema, respectively; 49% and 46% for SP‐induced oedema, respectively).
COX‐2 mRNA was undetectable in saphenous nerves and paw skin biopsy samples, before and after saphenous nerve stimulation.
A mast cell stabilizer, cromolyn, and a H1 receptor antagonist, mepyramine, significantly inhibited neurogenic (51% and 43%, respectively) and SP‐induced oedema (67% and 63%, respectively).
The co‐injection of LOX inhibitors and compound 48/80 did not alter the effects of compound 48/80. Conversely, ethacrynic acid had a significant potentiating effect. The pharmacological profile of the effect of COX inhibitors on compound 48/80‐induced oedema was similar to that of neurogenic and SP‐induced oedema.
The polysaccharide, fucoidan (an inhibitor of leukocyte rolling) did not affect neurogenic or SP‐induced oedema.
Thus, (i) SP‐induced leukotriene synthesis is involved in the development of neurogenic oedema in rat paw skin; (ii) this leukotriene‐mediated plasma extravasation might be independent of mast cell activation and/or of the adhesion of leukocytes to the endothelium; (iii) COX did not appear to play a significant role in this process.

British Journal of Pharmacology (2001) 132, 1581–1589; doi:10.1038/sj.bjp.0703950
Role of the epithelium in opposing H2O2‐induced modulation of acetylcholine‐induced contractions in rabbit intrapulmonary bronchiole
Authors: Asano Takayuki , Hattori Tomonori , Tada Toyohiro , Kajikuri Junko , Kamiya Toshio , Saitoh Michihiro , Yamada Yasuo , Itoh Makoto , Itoh Takeo 
Published: January 2005

The role played by the epithelium in H2O2‐induced modulation of the mechanical responses induced by acetylcholine (ACh) in rabbit intrapulmonary bronchioles was investigated in epithelium‐intact and ‐denuded strips.
When ACh (3 μM) was applied intermittently, H2O2 (30 μM) enhanced the ACh‐induced contractions in epithelium‐intact strips. In contrast, in epithelium‐denuded strips H2O2 (30 μM) inhibited such contractions. At higher concentrations, H2O2 concentration‐dependently attenuated the ACh‐induced contractions in both epithelium‐intact and ‐denuded strips, its action being more potent in the latter strips than in the former.
Diclofenac (a cyclo‐oxygenase inhibitor; 3 μM) reduced the H2O2‐induced enhancement of ACh‐contractions in epithelium‐intact strips but had no effect on the H2O2‐induced inhibition in epithelium‐denuded strips. NG‐nitro‐L‐arginine did not alter the effect of H2O2 on ACh‐induced contractions in epithelium‐intact strips.
Catalase (500 u ml−1) completely blocked both H2O2‐induced effects on ACh‐contractions (enhancement and inhibition). Neither superoxide dismutase (200 u ml−1) nor deferoxamine (0.5 mM) had any effect on H2O2‐induced inhibition in epithelium‐denuded strips.
Aminotriazole (an inhibitor of catalase; 50 mM) significantly potentiated the H2O2‐induced inhibition of ACh‐contractions in epithelium‐intact strips but not in epithelium‐denuded strips.
The density ratio for catalase (epithelium‐intact over ‐denuded strips) analysed by Western blot was about 2.1, suggesting that epithelium contains more catalase than smooth muscle.
It is concluded that in rabbit intrapulmonary bronchioles, H2O2 has dual actions on ACh‐contractions. It is suggested that the epithelium may act as a powerful biochemical barrier via both the action of catalase (scavenging H2O2) and the release of bronchoconstrictor prostaglandins, thus attenuating the H2O2‐induced modulation of ACh‐contractions.

British Journal of Pharmacology (2001) 132, 1271–1280; doi:10.1038/sj.bjp.0703956
Agonist trafficking of Gi/o‐mediated α2A‐adrenoceptor responses in HEL 92.1.7 cells
Authors: Kukkonen Jyrki P , Jansson Christian C , Åkerman Karl E O 
Published: January 2005

The ability of 19 agonists to elevate Ca2+ and inhibit forskolin‐induced cyclic AMP elevation through α2A‐adrenoceptors in HEL 92.1.7 cells was investigated. Ligands of catecholamine‐like‐ (five), imidazoline‐ (nine) and non‐catecholamine‐non‐imidazoline‐type (five) were included.
The relative maximum responses were similar in both assays. Five ligands were full or nearly full agonists, six produced 20 – 70% of the response to a full agonist and the remaining eight gave lower responses (<20%) so that their potencies were difficult to evaluate.
Marked differences in the potencies of the agonists with respect to the two measured responses were seen. The catecholamines were several times less potent in decreasing cyclic AMP than in increasing Ca2+, whereas the other, both imidazoline and ox‐/thiazoloazepine ligands, were several times more potent with respect to the former than the latter response. For instance, UK14,304 was more potent than adrenaline with respect to the cyclic AMP response but less potent than adrenaline with respect to the Ca2+ response.
All the responses were sensitive to pertussis toxin‐pretreatment. Also the possible role of PLA2, β‐adrenoceptors or ligand transport or metabolism as a source of error could be excluded. The results suggest that the active receptor states produced by catecholamines and the other agonists are markedly different and therefore have different abilities to activate different signalling pathways.

British Journal of Pharmacology (2001) 132, 1477–1484; doi:10.1038/sj.bjp.0703964
Activity of mu‐ and delta‐opioid agonists in vas deferens from mice deficient in MOR gene
Authors: Maldonado Rafael , Severini Cintia , Matthes Hans W D , Kieffer Brigitte L , Melchiorri Pietro , Negri Lucia 
Published: January 2005

Mice lacking the mu‐opioid receptor have been recently generated. Centrally mediated responses of mu‐opioid agonists are suppressed whereas some of the delta‐opioid responses are preserved in these mutant mice.
The vas deferens bioassay has been used in this study to investigate the functional activity at a peripheral level of mu‐ and delta‐opioid agonists in mice lacking mu‐opioid receptors.
The different mu‐opioid agonists evaluated, morphine, DAMGO, dermorphin and [Lys7]‐dermorphin produced an inhibitory response in vas deferens from wild‐type mice but had no relevant activity on vas deferens from mutant mice.
The selective delta‐opioid agonists DPDPE, BUBU, deltorphin I, deltorphin II and [D‐Met2]‐deltorphin induced inhibitory effects in vas deferens from both wild‐type and mutant mice. However, the biological activities of these ligands were slightly reduced in preparations from mutant mice. The inhibitory responses of all these delta‐opioid agonists were prevented by the administration of the selective delta‐opioid antagonist naltrindole.
These data indicate that delta‐opioid agonists, but not mu‐opioid agonists, are biologically active in vas deferens from mice lacking mu‐opioid receptors. The decreased response of delta‐agonists in mutant mice suggests that some cooperativity may exist between mu‐ and delta‐opioid receptors in these vas deferens preparations.

British Journal of Pharmacology (2001) 132, 1485–1492; doi:10.1038/sj.bjp.0703966