1,721,188 research outputs found
SYNTHESIS AND PHARMACOLOGICAL CHARACTERIZATION OF RIBOSE-MODIFIED ADENOSINE DERIVATIVES AS P1 RECEPTOR LIGANDS
No full textAdenosine, the natural ligand of P1 receptors, is implicated in the control of many physiological and pathological conditions such as inflammation, pain, cardiovascular and central nervous system (CNS) diseases.1
P1 receptors belong to the large family of GPCR receptors and are divided in four subtypes: A1, A2A, A2B and A3 adenosine receptors (ARs). Even though a large number of P1 ligands have been synthesized and characterized byin vitro and in vivo pharmacological studies, only very few of them are commercially available.
Modifications at the ribose moiety and substitution at the N6-position of adenosine, lead to adenosine derivatives endowed with increased potency at A1 or A3AR. Our previous SAR studies showed that the replacement of OH at 5’-position of the ribose moiety of N6-substituted adenosine derivatives by a chlorine improved A1AR potency and selectivity versus A3AR, with 5′-chloro-5′-deoxy-N6-(±)-(endo- norborn-2-yl)-adenosine (5′Cl5′d-(±)-ENBA) as one of the most potent and selective A1AR agonists,2 while a 5’-C-ethyl-tetrazolyl moiety maintained the A1AR potency, but restored high A3AR affinity, leading to very potent dual A1AR and A3AR ligands.3 Interestingly, both modifications at 5’-position of adenosine derivatives brought to human A3AR antagonism.
In order to further explore the structural determinants of this class of P1 ligands, a new series of ribose- modified N6-substituted adenosine derivatives was synthesized and their pharmacological profile was assayed. The results of this study will be discussed.References
1. Jacobson KA, Muller CE, Neuropharmacology 2015, doi: 10.1016/J.neuropharm.2015.12.001.
2. (a) Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.; Grifantini, M. J. Med. Chem. 2009, 52, 2393−2406. (b) Luongo, L.; Petrelli, R.; Gatta, L.; Giordano, C.; Guida, F.; Vita, P.; Franchetti, P.; Grifantini, M.; De Novellis, V.; Cappellacci, L.; Maione, S. Molecules 2012, 17, 13712−13726. (c) Luongo, L.; Guida, F.; Imperatore, R.; Napolitano, F.; Gatta, L.; Cristino, L.; Giordano, C.; Siniscalco, D.; Di Marzo, V.; Bellini, G.; Petrelli, R.; Cappellacci, L.; Usiello, A.; de Novellis, V.; Rossi, F.; Maione, S. Glia 2014, 62, 122−132.
3. Petrelli, R.; Torquati, I.; Kachler, S.; Luongo, L.; Maione, S.; Franchetti, P.; Grifantini, M.; Novellino, E.; Lavecchia, A.; Klotz, K.-N-; Cappellacci, L. J. Med. Chem. 2015, 58, 2560-2566
Effects of 5'-chloro-5'-deoxy-N6-(±)-endo-norbornyl-adenosine, a potent and highly selective A1 adenosine receptor agonist, on neuropathic pain-induced behavioural and morphological changes in spinal microglia
No full textThis study was undertaken in order to investigate the effect of chronic treatment with 5'-chloro-5'-deoxy-N6-(±)-endo-norbornyladenosine (5'Cl5'd-(±)-ENBA),1 a potent and highly selective adenosine A1 receptor agonist, on thermal hyperalgesia and mechanical allodynia in a mouse model of neuropathic pain, the spared nerve injury (SNI). Chronic systemic administrations of 5'Cl5'd-(±)-ENBA (0.5 mg/kg, i.p once a day) reduced both thermal hyperalgesia and mechanical allodynia 3 and 7 days after SNI, in a way prevented by DPCPX (3 mg/kg, i.p.), a selective A1 receptor antagonist. SNI induced spinal changes on microglial activation ipsilaterally to the nerve injury. Moreover, 5'Cl5'd-(±)-ENBA significantly reduced microglial activation in vitro. In particular pre-incubation with 5'Cl5'd-(±)-ENBA prevented the microglial morphological changes induced by LPS, ATP, LPS+ATP challenges. Our results demonstrated an involvement of A1 receptors in the increase of nociceptive thresholds and in spinal changes occurred in neuropathic pain. In addition, 5'Cl5'd-(±)-ENBA antiallodynic and antihyperalgesic effects could be mediated by the A1 receptors expressed on microglial cells.
(1) Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.; Grifantini, M. J. Med. Chem. 2009, 52, 2393-2406
Ketones and pain: unexplored role of hydroxyl carboxylic acid receptor type 2 in the pathophysiology of neuropathic pain.
No full textThe mechanisms underlying neuropathic pain are poorly understood. Here we show the unexplored role of the hydroxyl carboxylic acid receptor type 2 (HCAR2) in 2 models of neuropathic pain. We used an oral treatment with dimethyl fumarate and the HCAR2 endogenous ligand -hydroxybutyrate (BHB) in wild-type (WT) and HCAR2-null mice. We found an up-regulation of the HCAR2 in the sciatic nerve and the dorsal root ganglia in neuropathic mice. Accordingly, acute and chronic treatment with dimethylfumarate (DMF) and BHB reduced the tactile allodynia. This effect was completely lost in the HCAR2-null mice after a 2-d starvation protocol, in which the BHB reached the concentration able to activate the HCAR2-reduced tactile allodynia in female WT mice, but not in the HCAR2-null mice. Finally, we showed that chronic treatment with DMF reduced the firing of the ON cells (cells responding with an excitation after noxious stimulation) of the rostral ventromedial medulla. Our results pave the way for investigating the mechanisms by which HCAR2 regulates neuropathic pain plasticity.Boccella, S., Guida, F., De Logu, F., De Gregorio, D., Mazzitelli, M., Belardo, C., Iannotta, M., Serra, N., Nassini, R., de Novellis, V., Geppetti, P., Maione, S., Luongo, L. Ketones and pain: unexplored role of hydroxyl carboxylic acid receptor type 2 in the pathophysiology of neuropathic pain
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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