<p> Pulmonary hypertension (PH) is a progressive disorder characterized by increased vascular obstruction and decreased pulmonary blood flow leading to elevated pulmonary vascular resistance, right heart failure, and death. The vascular endothelium has an essential role in the maintenance of low vascular tone and endothelial dysregulation is thought to be the initiating event in the development of PH. The NO-sGC-cGMP pathway is an important therapeutic target for the treatment of pulmonary hypertension. In order to investigate novel therapeutic agents targeting the NO-sGC-cGMP pathway in the pulmonary vascular bed of the intact rat, we hypothesized that responses to agonists of the NO-sGC-cGMP pathway will be tone dependent, independent of endogenous NO, and attenuated when sGC is inhibited with ODQ. The magnitude of pulmonary vasodilator responses to the NO donors was increased when pulmonary vasoconstrictor tone was increased with the thromboxane receptor agonist U46619. Pulmonary and systemic vasodilator responses to the nitrosovasodilators were not altered by treatment with the NOS inhibitor L-NAME but were attenuated by ODQ, an agent which oxidized the heme iron of sGC. These data indicate that decreases in pulmonary and systemic arterial pressures in response to iv injection of nitrosovasodilators are tone dependent, independent of endogenous NO, and require the presence of normally reduced heme iron on sGC. Pulmonary and systemic vasodilator responses to novel agents targeting the sGC-cGMP pathway were investigated. Vasodilator responses to Bay-41-8543 were attenuated by L-NAME or ODQ and responses were enhanced when pulmonary arterial pressure was increased with U46619. Responses to the sGC activator Bay 60-2770 were enhanced by L-NAME or ODQ and when pulmonary arterial pressure was increased with U46619. These results suggest that Bay 41-8543 would be useful in the treatment of pulmonary hypertension in disease states where sGC is in the normally reduced state and low levels of NO are present. These data also indicate that Bay 60-2770 would be useful in disease states where sGC is oxidized and non-responsive to NO or sGC stimulating agents. ODQ has been used in investigations of the NO-sGC-cGMP-cGKi pathway in biochemical and isolated vessel studies. However little is known about the effects of OQD on cardiovascular responses in-vivo studies and we hypothesized that ODQ would be useful in studying responses to agents which act on the NO-sGC-cGMP pathway in-vivo. Moreover, we hypothesized that treatment with ODQ would inhibit responses to NO donors and to the endothelial dependent vasodilators Ach and BK. In these studies, ODQ in a dose that significantly attenuated responses to 6 different nitrosovasodilators did not significantly alter pulmonary and systemic responses to Ach or BK suggesting that they ac by another mechanism which may involve TRPV4 channels. The results of these studies show that inorganic nitrite which is converted to vasoactive NO by xanthine oxidoreductase or aldehyde dehydrogenase and nebivolol a beta adrenergic receptor antagonist that releases NO have a beneficial effect in monocrotaline induced pulmonary hypertension in the rat.</p>

Pharmacokinetic studies of acute oral doses of d,1-methadone (25 mg kg('-1)) were carried out on adult non-pregnant, pregnant and lactating female guinea pigs, quantitating the blood plasma methadone levels by gas-liquid chromatography following solvent extraction. The mean (beta) t(, 1/2) of methadone in these animals were 7.7 h, 14.6 h and 11.6 h, respectively. Differences in plasma t(, 1/2) were attributable to difference in drug metabolism. Repeated administration of methadone neither significantly altered the (beta) t(, 1/2) nor had any significant influence on the in vitro hepatic microsomal monooxygenases (nitroanisole O-demethylase (OD) and aniline hydroxylase (AH)). In contrast, methadone treatment markedly reduced the hepatic microsomal glucuronosyltransferase (GT) activity in adult and in perinatal animals. / Methadone (25 mg kg('-1) every 12 h for 2 days) administered to pregnant (60-65 days of gestation) or nursing (0 to 8 days of post-partum) dams resulted in the acquisition of higher tissue levels of the drug in pups by transplacental passage than that obtained via the milk. The pattern distribution of methadone in the pup was different from that observed in the dam, exceedingly high levels of methadone being found in the brain of the perinatal individual.

The structure and the regulation of the hepatic $ alpha sb1$-adrenergic receptors have been studied in the rat. The in vitro incubation of isolated liver cells in a serum-free buffer for 4 hr leads to the conversion of the adrenergic activation of glycogen phosphorylase from an $ alpha sb1$- to a $ beta$-adrenoceptor-mediated event. This change is associated with no change in the glycogenolytic response to vasopressin and a reduction of the glycogenolytic response to glucagon. The time-dependent shift in the adrenergic control of glycogenolysis does not influence the density or the affinity of ($ sp3$H) prazosin-labeled $ alpha sb1$-receptors and ($ sp3$H) CGP-12177-labeled $ beta$-receptors. The change in the adrenergic control of glycogenolysis is reversed by a 30-min incubation with 50 nM lipomodulin, whereas in freshly isolated cells lipomodulin doesn't affect the predominant $ alpha$-receptor response. Conversely, exposure of freshly isolated cells to a monoclonal antibody to lipomodulin in the presence of 10 $ mu$M phenylephrine, or to 2 $ mu$g/ml mellitin, results in a shift in the adrenergic control of glycogenolysis from $ alpha sb1$- to $ beta$-type within 30 min. It is proposed that coupling of hepatic $ alpha sb1$- and $ beta$-adrenoceptors to postreceptor pathways is regulated in an inverse reciprocal manner by changes in membrane phospholipase A$ sb2$ activity. / The mechanism of activation of the Ca$ sp{2+}$-linked receptors for vasopressin and adrenaline was studied in isolated liver cells. Sequential treatment of cells with 10$ sp{-7}$M vasopressin and 1 mM of bifunctional cross-linker disuccinimidyl suberate (DSS), followed by washout of the drugs, doesn't influence the dissociation of vasopressin from its receptor, but results in permanent activation of glycogen phosphorylase. Similarly, when the cells are stimulated with 10$ sp{-5}$M adrenaline and treated with DSS, glycogen phosphorylase is permanently activated. It is proposed that agonist activation of vasopressin or $ alpha sb1$-adrenergic receptors involves the microaggregation of receptors or their coupling to other membrane proteins. / A novel irreversible antagonist for the $ alpha sb1$-adrenergic receptors, I-phenoxybenzamine (I-POB) has been synthesized and pharmacologically characterized. We have shown that I-POB binds to the $ alpha sb1$-adrenergic receptor in rat liver plasma membranes with high affinity (K$ sb{ rm i}$ = 2 nM). (Abstract shortened with permission of author.)

Background. Congestive Heart Failure (CHF) causes arrhythmogenic remodeling in both atria and ventricles, but potential differences between atrial and ventricular remodeling in CHF have not been studied. / Methods and results. We examined atrial and ventricular tissues from dogs with CHF induced by ventricular tachypacing (VTP, 240/min) for 0 (control) or 24 hrs, 1, 2, or 5 wks. Tissue angiotensin-II concentration (ELISA) increased to steady state at 24 hrs, and was significantly higher in LA than LV. VTP caused tissue apoptosis, inflammatory-cell infiltration and cell-death, with maximum changes in LA being transient and larger than in LV. MAP kinase activation (Western blot) was rapid (within 24 hrs) in LA, but smaller and slower (p38, JNK) or non-significant (ERK) in LV. The 25-kDa activated form of TGFbeta1, a particularly important profibrotic mediator in atria, increased significantly (Western blot) in LA at 24 hrs and 1 wk, but was not changed in LV. Substantial fibrosis developed in LA, but was much less important in LV. / Conclusions. There are qualitative and quantitative differences in LA and LV remodeling in experimental CHF, with important potential consequences for underlying mechanisms and therapeutic approaches.

Opioid drugs acting at the mu opioid receptor (muOR), such as morphine, represent the most commonly prescribed analgesics for the clinical management of moderate to severe pain. However, the clinical use of muOR agonists is limited by the occurrence of undesirable effects such as respiratory depression and the tendency to produce tolerance and/or dependence with repeated administration. delta opioid receptor (deltaOR) activation produces antinociception with reportedly less deleterious effects when compared to muOR activation. However, animal studies have revealed that deltaOR-mediated antinociceptive effects are modest compared to muOR-elicited ones. Thus, we studied the regulation of deltaOR trafficking in the rodent central nervous system with the intention of modifying the density of this receptor at the cell surface and thereby improve deltaOR agonist potency. Stimulation with morphine for 48 hours produced increased deltaOR cell surface density both in vitro in primary cortical neurons in culture and in vivo in neurons within the dorsal horn of the spinal cord of rodents. This enhanced deltaOR cell surface density was a trafficking event and was not due to an overall increase in deltaOR expression. In vivo, the increased deltaOR cell surface density was accompanied with enhanced antinociceptive potency of intrathecally administered muOR agonists and augmented internalization of a fluorescent deltaOR agonist in the dorsal horn. This effect was observed following pretreatment with various muOR agonists and was abolished in muOR knock-out mice, demonstrating that activation of muOR was critical for enhanced targeting of deltaOR to neuronal plasma membranes and the observed increased antinociceptive responses. These changes in deltaOR function and subcellular localization were not associated with the development of tolerance to muOR agonists and were reversed 48 hours after the cessation of treatment with morphine. This muOR-induced enha

Androgens are responsible for maintaining epididymal structure and functions. However, little is known about how androgen action is mediated and the identity of mechanisms underlying the restoration of epididymal cell integrity after androgen deprivation. It was therefore the goal of this thesis to determine the initial and sequential role of androgen action in altering cellular architecture and function in an androgen-deprived condition. / The first objective was to elucidate the morphological changes in the regressed rat epididymal cell epithelium before and after hormone replacement. Using morphometric analysis and antibodies to cell proliferation markers, we determined changes in epithelial cell height and lumen diameter, as well as in the number of nuclei labeled, respectively, in different regions and at various time points after testosterone replacement in the regressed epididymis. We concluded that testosterone induces an increase in the number of new cells and re-expansion of existing cells in the regressed epididymis. / The second objective was to determine the sequence of gene activation or suppression that occurs in an androgen deprived tissue upon re-administration of the two active metabolites of testosterone, dihydrotestosterone and estradiol by using Affymetrix Rat Genome Microarray chips. Interestingly, there are few genes that were regulated by estradiol, while many were affected by dihydrotestosterone. Using Pathway Assist software, we identified the early response pathway activated by dihydrotestosterone. Epidermal growth factor (EGF) and insulin-like growth factor (IGF1) appear to play an important role in the pathway due to their function in regulation and expression of many other genes. / Lastly, we established the intracellular signaling pathway that may play a central role in mediating androgen action in restoring epithelial cell integrity in the epididymis. Involvement of two potential pathways activated by dihydrotestosterone, MAPK/ERK and AKT, in the proximal caput (PC-1) epididymal cell line was investigated. Using specific inhibitors for each pathway and an androgen receptor antagonist, we assessed the involvement of the androgen receptor in these pathways. IGF1 and EGF receptors were found to be the important mediators of MAPK/ERK pathway activations. / Collectively, the results obtained from these studies provide a greater understanding of the mechanisms of androgen action in the epididymis. / Les androgènes sont responsables du maintien de la structure et des fonctions de l'épididyme. Cependant, nous en savons très peu sur la manière dont les androgènes agissent et l'identité des méchanismes sous-jacents à la restauration de l'intégrité cellulaire épididymale après privation des androgènes. Le but de cette thèse a donc été de déterminer le rôle initial et séquentiel de l'action des androgènes dans l'alteration de la structure architecturale et de la fonction en condition de privation des androgènes. / Le premier objectif a été d'élucider les changements morphologiques dans l'épithélium cellulaire épididymal dans le rat régressé avant et après remplacement de l'hormone. En utilisant une analyse morphométrique et des anticorps pour marquer la prolifération cellulaire, nous avons respectivement déterminé les changements dans la hauteur des cellules épithéliales et du diamètre de la lumière ainsi que le nombre de noyaux marqués dans différentes régions et à différents moments après remplacement de la testostérone (T) dans l'épididyme régressé. Nous avons conclu que la T induit une augmentation du nombre de nouvelles cellules et une ré-expansion des cellules existantes dans l'épididyme régressé. / Le second objectif a été de determiner la sequence d'activation ou de suppresion des gènes qui arrivaient dans un tissu privé d'androgènes après ré-administration des deux metabolites actifs de la T, dihydrotestostérone (DHT) et l'estradiol (E2) en utilisant des micropuces Affymetrix Rat Genome. Peu de gènes ont été régulés par l'E2, alors que beaucoup ont été affectés par la DHT. En utilisant, le programme Pathway Assist, nous avons identifé le chemin de réponse activé tôt par la DHT. Le facteur EGF (Epidermal growth factor) et le facteur IGF1 (Insulin-like growth factor) semblent jouer un rôle important dans le chemin dû à leur fonction dans la régulation et l'expression de plusieurs gènes. / Finalement, nous avons établi le chemin de signalisation intracellulaire qui pourrait jouer un rôle central dans la médiation de l'action des androgènes pour restaurer l'intégrité cellulaire épithéliale dans l'épididyme. L'implication de deux chemins potentiels activés par la DHT, MAPK/ERK et AKT, dans la lignée cellulaire épididymale PC-1 a été exploré. En utilisant des inhibiteurs spécifiques pour chaque chemin et un antagoniste du récepteur à androgènes (AR), nous avons évalué la participatation d'AR dans ces chemins. Les récepteurs IGF1 et EGF ont été identifés comme des médiateurs importants de l'activation du chemin MAPK/ERK. / Ensemble, les résultats obtenus de ces etudes apportent une meilleure comprehension des mechanisms d'action des androgens dans l'épididyme.

One third of drugs in development are water insoluble, and one half of all drugs fail in trials because of poor pharmacokinetics. Block copolymer micelles are nanosized particles that can solubilize hydrophobic drugs and coincidentally alter their kinetics in vitro and in vivo. In using such micelles it is important that the drug is not lost due to premature vehicle disassembly and that its effectiveness is not diminished by unfavorable distribution of the micelles. Disintegration of micelles depends on a number of environmental conditions, with consequent variation in drug release rates; these rates, however, are always faster than those which occur by simple diffusion from intact micelles. When these thesis studies began no data was available on integrity of micelles in cells and in vivo, and in vitro studies of distribution of micelles were scarce. This thesis begins by providing a detailed account of the distribution of model block copolymer micelles in live cells using fluorescent-labeled polymer and confocal microscopy. Next, the evidence for endocytosis of micelles, and their effectiveness in delivering a model micelle-incorporated agent anthra[1,9-cd]pyrazol-6(2H)-one (SP600125) is presented. The thesis ends with an account of the disruption of integrity of micelles in vitro and in vivo, made possible by a novel application of a fluorogenic-based assessment that enables the monitoring of the integrity of micelles under complex biological conditions. / Block copolymer micelles were made from Food and Drug Administration approved polymers poly(caprolactone) and poly(ethylene oxide). In vitro studies were done in cell lines (PC12, NIH/3T3, T24) and primary cultures (human islets of Langerhans). In vivo studies were done in hairless SKH-1 mice. The in vitro studies demonstrated the uptake of micelles by all investigated cells. The micelles were confined to the cytoplasmic compartment, with no detectable nuclear localization. Detailed studies in PC12 cells revealed co-localization of micelles with several organelle selective dyes (mitochondria, Golgi apparatus, endoplasinic reticulum). Pharmacological manipulations (sucrose, FK506, wortmannin, horseradish peroxidase, methyl-beta-cyclodextrin) revealed an endocytotic uptake of micelles and suggested a significant contribution of clathrin-mediated endocytosis. The effectiveness of c-Jun NH2-terminal kinases (JNK)---micelle-incorporated inhibitor, SP600125, was demonstrated in human islets of Langerhans challenged with cytokines. Micelle-incorporated SP600125 prevented the cytokine induced cell death of islets at a lower starting concentration (1.5 $M in the medium) compared to free drug (20 muM). / Lastly, a graded loss of integrity of micelles was demonstrated in media with increasing biological complexity, in cells, and, as a proof of principle, in vivo. Taken together, the results presented in this thesis suggest (i) a need for assessment of the integrity of micellar drug carriers under biological conditions to further improve the micelle-based drug delivery systems, (ii) the identification of the contribution of micelles with disrupted integrities to the internalization and effectiveness of micelle-incorporated drugs, (iii) an assessment of cellular retention and degradation of internalized polymers. That the pharmacokinetics of micelle-incorporated drugs reported in recent clinical trials showed only modest improvements over non-micelle delivered agents may at least in part be due to disruption of micelle integrity. Additional studies are needed to understand exactly where the delivery system goes, when and where is the drug released, and how recent advances in vehicle design and targeting can be harnessed to overcome the present challenges and realize the full potential of polymeric micelles.

Periventricular leukomalacia (PVL) is the principal form of brain injury in preterm neonates. In addition to the vasculopathy associated with hypoxicischemic injury, PVL is characterized by the loss of progenitor oligodendrocytes (OLs). Oxidant stress and lipid peroxidation increase in hypoxic-ischemic injuries, particularly in the immature brain. We hypothesized that the major lipid peroxidation products isoprostanes 15-F2t-IsoP and 15-E2t-IsoP, and lysophosphatidic acid (LPA) could be implicated in the pathogenesis of PVL by affecting the survival of brain OLs and microvascular endothelial cells (ECs). / Cytotoxicity of the lipid peroxidation products was assessed on cultured rat progenitor and mature OLs and piglet cerebromicrovascular ECs using the MTT assay. The two isoprostanes displayed different cytotoxic profiles. 15-E 2t-IsoP induced progenitor OL death but did not affect mature OL or microvascular EC survival. In contrast, 15-F2t-IsoP induced death of ECs but not of progenitor and mature OLs. As well, LPA triggered brain microvascular EC death. In all cases, cells did not exhibit classical features of apoptosis (nuclear condensation, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL), caspases activation) but displayed signs of oncotic necrosis (propidium iodide incorporation, cell swelling, lactate dehydrogenase release). Cytotoxicity conveyed by both isoprostanes involved TxA2 synthesis, as determined by radioimmunoassay and by the protective effect of TxA2 synthase inhibitors. In addition, progenitor OLs were susceptible to 15-E2t-IsoP due to their low antioxidant defenses. On the other hand, LPA caused EC death through the LPA1 receptor which activated the stress activated protein kinases p38 MAPK and JNK; these kinases were responsible for the decreased intracellular glutathione content observed and the induction of iNOS which caused protein nitrosylation. EC death and neuromicrovascular degeneration caused by 15-F2t-IsoP and LPA were observed ex vivo on isolated microvessels and brain explants and in vivo, with intracerebroventricular infusion and intraocular injections. / These novel data implicate 15-E2t-IsoP, 15-F2t-IsoP and LPA as major lipid peroxidation products that may contribute to the genesis of PVL by affecting the survival of progenitor OLs and microvascular ECs.

Ischemia-reperfusion (I/R) injuries are daily phenomena in the operating room (OR), as surgeons use tourniquets or vascular clamps in order to decrease blood loss and obtain a clean surgical field. Several injurious cellular and vascular processes occur during I/R injury, such as enhanced oxidative, inflammatory and thrombotic reactions. Chronic pain and other painful syndromes are well-established possible consequences of I/R injury. Using I/R injury to produce chronic post-ischemia pain (CPIP) in the rat, we demonstrate that glycemia modulation during the procedure can significantly impact mechanical and cold allodynia for at least 21 days after the I/R injury. Fasting and insulin administration significantly protect against mechanical and cold allodynia, whereas normal feeding and dextrose administration exert significant deleterious effects on the pain (mechanical and cold) thresholds. Using enzyme-linked immunosorbent assay (ELISA), we then show that nuclear factor kappa-B (NFκB), a key pro-inflammatory transcription factor, is increased in the ipsilateral plantar muscles and dorsal horn of the hyperglycemic animals during I/R injury, compared with relatively hypoglycemic animals. We further demonstrate the importance of NFκB in glycemia-modulated mechanical allodynia by administrating SN50, a cell-permeable peptide that blocks nuclear translocation of NFκB, to groups of CPIP rats with different levels of glycemia during the I/R injury. The anti-allodynic dose-response curves of these groups exhibit clear shifts between them: the dose-response curve of the hyperglycemic group is significantly right-shifted compared to the hypoglycemic group, which reinforces the previous demonstration of different intrinsic NFκB levels depending on the glycemia during I/R injury. Our results suggest that NFκB may play a critical role in any procedure involving I/R injury, and the post-procedural pain could be significantly decreased by tight glycemic control during the procedure. / Les blessures d'ischémie-reperfusion sont des phénomènes quotidiens dans la salle d'opération; les chirurgiens utilisent en effet des tourniquets ou des pinces vasculaires hémostatiques pour diminuer les pertes sanguines et obtenir une exposition adéquate. Plusieurs phénomènes cellulaires et vasculaires délétères se produisent durant une blessure d'ischémie-reperfusion, tels que des processus oxydatifs, inflammatoires et thrombotiques amplifiés et accélérés. De la douleur chronique ainsi que d'autres syndromes douloureux sont des conséquences bien reconnues des blessures d'ischémie-reperfusion. Utilisant une blessure d'ischémie-reperfusion chez le rat pour produire de la douleur post-ischémique chronique (DPCI), nous démontrons que la modulation de la glycémie durant la procédure peut avoir un impact significatif sur l'allodynie mécanique et au froid pour au moins 21 jours après la blessure d'ischémie-reperfusion. Le jeûne et l'administration d'insuline confèrent une protection significative contre l'allodynie mécanique et au froid, alors qu'une alimentation normale et l'administration de dextrose exercent à l'opposé des effets néfastes sur les seuils de douleur (mécanique et au froid). Utilisant une méthode immuno-enzymatique (ELISA), nous démontrons que le facteur nucléaire de transcription kappa B (NFκB), un facteur de transcription pro-inflammatoire critique, est augmenté dans les muscles plantaires et la moelle épinière (racine dorsale) des animaux hyperglycémiques durant la blessure d'ischémie-reperfusion, en comparaison aux animaux relativement hypoglycémiques. Nous démontrons également l'importance du facteur de transcription NFκB dans l'allodynie mécanique modulée par la glycémie, en administrant SN50, un peptide qui bloque la translocation nucléaire de NFκB, à des groupes de rats DPIC ayant eu des niveaux de glycémie différents durant la blessure d'ischémie-reperfusion. Les courbes dose-réponse anti-allodyniques présentent des différences significatives entre elles; la courbe dose-réponse du groupe hyperglycémique est significativement déplacée à droite en comparaison au groupe hypoglycémique, ce qui renforce la démonstration précédente de niveaux intrinsèques de NFκB significativement différents selon la glycémie durant la blessure d'ischémie-reperfusion. Nos résultats suggèrent que le facteur de transcription NFκB pourrait jouer un rôle déterminant dans la DPIC survenant après une blessure d'ischémie-reperfusion et que la douleur post-opératoire pourrait être significativement diminuée par un contrôle strict de la glycémie durant la procédure.

The F prostanoid receptor (FP receptor) is a GPCR that, upon binding of prostaglandin F2alpha (PGF2alpha), mediates IP3 production and PKC-dependent MAPK activation. We report that AL-8810, a characterized antagonist for PGF2alpha-dependent IP3 production, potently activates ERK1/2 in a PKC-independent manner, since PGF2alpha induced PKCbeta1-GFP translocation, while AL-8810 did not. AL-8810, though, induced EGFR phosphorylation, and the resultant ERK1/2 activation was inhibited by an EGFR antagonist, which suggested a transactivation signalling pathway. Batimastat, a matrix metalloprotease (MMP) inhibitor abolished both AL-8810- and PGF2alpha-induced ERK1/2, and therefore PGF2alpha may also signal through EGFR-independent transactivation. In osteoblasts, both PGF2alpha and AL-8810 activated MAPK in an EGFR-dependent manner, though PKC remained essential for PGF2alpha, as IL-6 and cell proliferation (known PKC effects) were induced by PGF2alpha but not AL-8810. Here, we highlight the biased signalling of AL-8810 on FP receptor produced MAPK through EGFR-MMP-mediated transactivation and also suggest a novel PGF2alpha-induced PKC-MMP, EGFR-independent, pathway. / Le récepteur F-prostanoïde (FP) est un récepteur de la famille des RCPG (récepteurs couplés aux protéines G), qui, une fois lié par son ligand naturel, la prostaglandine F2alpha (PGF2alpha), induit la production d'IP3, menant à l'activation de la protéine kinase C (PKC) suivie de l'activation des MAP kinases ERK1/2. Dans ce manuscrit, nous démontrons que l'AL-8810, étant reconnu comme un antagoniste de la production d'IP3 induite par le PGF2alpha, est capable d'activer la voie des ERK1/2 d'une manière indépendante à la PKC. En effet, nous démontrons que la PKCbeta1-GFP transloque à la membrane plasmique suite au traitement avec la PGF2alpha, alors que l'AL-8810 n'induit aucune translocation. Cependant, l'AL-8810, contrairement à la PGF2alpha, est capable d'induire la phosphorylation du récepteur à l'EGF (EGFR), menant à l'activation de ERK1/2. La phosphorylation de l'EGFR induite par l'AL-8810 est blocable par une antagoniste de l'EGFR, suggérant un mécanisme de transactivation de ce dernier. De plus, le batimastat, un inhibiteur non-spécifique des métalloprotéases matricielles (MMP) abolit l'induction des ERK1/2 par la PGF2alpha ainsi que par l'AL-8810, suggérant que la PGF2alpha signale probablement par un mécanisme indépendant de la transactivation de l'EGFR. Dans des cellules ostéoblastes, la PGF2alpha et l'AL-8810 activent ERK1/2 d'une manière dépendante au EGFR, même si la PKC demeure essentielle pour l'activation des voies en aval de la PGF2alpha, puisque l'interleukine-6 et la prolifération cellulaire (tous deux dépendants de la PKC) sont induits seulement par la PGF2alpha. En conclusion, nous montrons l'activation biaisée du FP par l'AL-8810 menant à l'activation de ERK1/2 via un mécanisme de transactivation par la voie EGFR-MMP. Ces résultats suggèrent aussi un nouveau mécanisme d'activation de ERK1/2 indépendant du EGFR et induit par la voie PKC-MMP.