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Patrizia Romualdi,1 Mariagrazia Grilli,2 Pier Luigi Canonico,3 Massimo Collino,4 Anthony H Dickenson5 1Department of Pharmacy and Biotechnologies Alma Mater Studiorum, University of Bologna, Bologna 40126, Italy; 2Laboratory of Neuroplasticity, Department Pharmaceutical Sciences, University of Piemonte Orientale, Novara 28100, Italy; 3Departiment of Pharmacological Sciences, University of Piemonte Orientale, Novara 28100, Italy; 4Department of Drug Science and Technology, University of Turin, Turin 10121, Italy; 5Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK Abstract: Chronic pain could be considered as a neurological disorder. Therefore, appropriate selection of the therapy, which should consider the pathophysiological mechanisms of pain, can result in a successful analgesic outcome. Tapentadol is an analgesic drug which acts both as a μ-opioid receptor (MOR) agonist and as a noradrenaline reuptake inhibitor (NRI), thereby generating a synergistic action in terms of analgesic efficacy, but not for the burden of adverse effects. Therefore, tapentadol can be defined as the first “MOR-NRI” drug. This molecule holds the potential to address at least some of the current limitations of analgesic therapy due to its unique mechanism of action and has shown to be safe and effective in the treatment of chronic pain of cancer and noncancer etiologies including nociceptive, neuropathic and mixed pain. In particular, the MOR component of tapentadol activity predominantly allows for analgesia in nociceptive pain; on the other hand, the NRI component contributes, now in a predominant manner, for analgesic efficacy in cases of neuropathic pain states. This paper will discuss recent pieces of evidence on the pathophysiology of pain, the background on tapentadol and then present some new studies on how the unique mechanism of action of tapentadol provides a key role in its analgesic efficacy in a number of pain states and with a favorable safety profile. Keywords: tapentadol, neuropathic pain, pain chronicization

Ulderico Freo,1 Patrizia Romualdi,2 Hans G Kress31Anesthesiology and Intensive Medicine, Department of Medicine DIMED, University of Padua, 35100 Padua, Italy; 2Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, 40126, Bologna, Italy; 3Department of Special Anaesthesia and Pain Medicine, Medical University/AKH of Vienna, Vienna, AustriaAbstract: Neuropathic pain (NP) is an enormous burden for patients, caregivers and society. NP is a pain state that may develop after injury of the peripheral or central nervous system because of a wide range of diseases and traumas. A NP symptom component can be found also in several types of chronic pain. Many NP patients are substantially disabled for years. Due to its chronicity, severity and unpredictability, NP is difficult to treat. Tapentadol is a central-acting oral analgesic with combined opioid and noradrenergic properties, which make it potentially suitable for a wide range of pain conditions, particularly whenever a NP component is present or cannot be excluded. In randomized controlled trials, tapentadol has proved to be effective in relieving NP in diabetic peripheral neuropathy and in chronic low back pain. In observational studies, tapentadol reduced NP in chemotherapy-induced peripheral neuropathies, blood and solid cancers, and the NP component in neck pain and Parkinson’s disease. This narrative review aims to provide clinicians with a broad overview of tapentadol effects on NP.Keywords: neuropathic pain, tapentadol, pain therapy

Renato Vellucci,1 Rocco Domenico Mediati,1 Silvia Gasperoni,1 Massimo Mammucari,2 Franco Marinangeli,3 Patrizia Romualdi4 1Palliative Care and Pain Therapy Unit, University Hospital of Careggi, Florence, 2Primary Care Unit, ASL RM 1, Rome, 3Department of Life, Health and Environmental Sciences, University of L’Aquila, l’Aquila, 4Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy Abstract: Breakthrough cancer pain (BTcP) is a common condition in oncological patients. However, its management is still suboptimal. Improved knowledge of BTcP and its management in clinical practice may have immediate importance for all physicians involved in the supportive care of cancer patients. This review critically discusses the most important concepts for the correct diagnosis of BTcP and presents some intriguing cases of the management of this condition in clinical practice. Overall, the most appropriate therapeutic choice appears to be a rapid-onset opioid (ROO), and in particular, the nasal route of administration is the quickest and most convenient mode of administration for the management of BTcP, especially when the patient needs rapid resolution of pain. To this end, intranasal fentanyl spray may have a particular relevance in clinical practice. Future research should focus on accepted definitions of BTcP to investigate the optimal management of this highly heterogeneous pain condition. Therapeutic decision-making of patients, clinicians, and payers will likely be driven from results of well-designed clinical trials of ROOs. Keywords: breakthrough cancer pain, rapid-onset opioid, intranasal fentanyl spray

Il sistema oppioide rapppresenta uno dei sistemi endogeni di neurotrasmissione/neuromodulazione ed è costitutito da specifici ligandi di natura peptidica e relativi recettori. Esso è presente a livello dell'S.N.C. ed in periferia ed è coinvolto nella modulazione di differenti e numerose funzioni.

Background and Aim: Alcohol alters several neurotransmitter systems within the brain and accumulated evidences indicate the endogenous opioid system as an important target of its action. We studied, in vitro and in vivo the molecular alterations occurring in the prodynorphin gene following different exposures to alcohol. Methods: Human neuroblastoma SH-SY5Y cells were exposed to low, clearly not intoxicating, and high etha- 208 European Opioid Conference 2011, Kraków, Poland nol concentrations at different time points. Sprague Dawley rats received alcohol intragastrically trying to mimic human drinking that establishes tolerance and dependence conditions. Real-time RT-PCR was used to assess the abundance of mRNAs of interest. DNA methylation was analyzed by Methylation Specific-Real Time PCR and bisulfite-Pyrosequencing. Specific histone modifications at gene promoters were evaluated by Chromatin ImmunoPrecipitation. Results: In the cellular model we demonstrated a temporal relationship between selective chromatin modifications induced by ethanol or acetaldehyde, and changes in prodynorphin gene expression were demonstrated. In the amygdala complex of alcoholtreated rats differential changes in prodynorphin gene expression changes were observed depending on the time of exposure; consistently, we propose potential epigenetic mechanisms responsible for these alterations, at least upong short ethanol exposure. Conclusion: Our findings indicate a linkage between gene expression alterations and epigenetic modulation in prodynorphin promoter, thus adding novel information on how the opioid system can be affected by alcohol in several ways. Studies are ongoing to evaluate the chromatin remodelling in the neuroplasticity occurring in the progression of alcohol abuse. It will be also of value to study the ability of epigenetic modulators in reverting dynorphin genetic/epigenetic alterations and alcohol abuse-related behaviours. Moreover, opioid drugs already available in alcoholism treatment could also have possible epigenetic modulating properties.

DARPP-32 (dopamine- and cAMP-regulated phosphoprotein) is a potent endogenous inhibitor of protein phosphatase-1, which plays an important role in dopaminergic transmission. A large body of evidence supports the key role of DARPP-32-dependent signalling in mediating the actions of multiple drugs of abuse, including cocaine, which, when acutely administered, increases the Thr34 phosphorylation of DARPP-32 in the striatal and cortical areas. In this study, we have examined the contribution of the kappa-opioid system to the regulation of DARPP-32 phosphorylation at Thr34, following acute cocaine administration, in selected rat brain areas. Results showed that a single injection of cocaine induces a significant increase in DARPP-32 phosphorylation at Thr34 in the hippocampus, caudate putamen and prefrontal cortex. In addition, pretreatment with the kappa opioid receptor agonist U-69593 prevented cocaine effects in all the investigated areas. These data could be considered consistent with the ability of kappa opioid agonists to attenuate many behavioural effects of cocaine, and support the hypothesis of the potential usefulness of these drugs as functional antagonists of cocaine.

The neuropeptide nociceptin/orphanin FQ (N/OFQ) is the endogenous ligand for the opioid-like receptor ORL-1 and is thought to be involved in pain transmission and modulation. Human studies have not yet defined its role in pain patients. The aims of this study were 1) to verify the presence of N/OFQ in the cerebrospinal fluid (CSF) of human controls and patients with chronic noncancer pain, including those treated with intrathecally administered morphine, and 2) to determine whether pain or treatment with long-term intrathecal morphine influences its levels. The CSF of 27 patients (nine controls and 18 with chronic noncancer pain, of whom 12 were treated chronically with intrathecally administered morphine and six were opioid naive) was analyzed, blindly, with radioimmunoassay methods. N/OFQ was detected in all patients. Mean CSF concentrations were lowest in the morphine-treated group and highest in the untreated chronic pain patients (12.06+/-1.19 and 57.41+/-10.06 fmol/ml, respectively), and the difference between the morphine-treated group and controls was statistically significant (44.72+/-13.56 fmol/ml, P

The opiate analgesic drugs today represent the more powerful instrument in the therapy of the pain and elicit their therapeutic action acting like endogenous substances, opioid peptides, natural ligands of the opioid receptors. They interact with specific receptors, physiologically present to central and peripheral levels to modulate different functions. Beside the most famous function concerning nociceptin sensibility, this system is also involved in the regulation of gastrointestinal, endocrine and independent functions, in the mechanisms of reward, dependence and in memory and learning processes. Opiates use is more and more diffusing in the practical analgesic and physicians should be able to modulate pain before that this becomes uncontrolled. The recent discovery of new opioid endogenous systems, like nociceptin, the development alternatives administration protocols and the discovery of new drugs with less addiction potentiality, opens the road to a better scientific understanding, to one more aimed therapeutic application and to more profitable and reassuring use of opiate drugs for the pharmacological control of pain. The expectations in this field of research are much high and future acquisitions will be able to help physicians to use the therapeutic instruments in the control of pain, in useful time before it is too late.

The opioid-like neuropeptide nociceptin/orphanin FQ (N/OFQ) and its receptor (NOP) are expressed in the substantia nigra (SN), a brain area containing dopamine neurons that degenerate in Parkinson's disease. Endogenous N/OFQ facilitates nigral glutamate release and inhibits nigrostriatal dopamine transmission and motor behavior. Here, we present evidence suggesting that endogenous N/OFQ may contribute to Parkinson's disease. Pharmacological blockade of the SN N/OFQ-NOP receptor system attenuated parkinsonian-like akinesia/hypokinesia in 6-hydroxydopamine hemilesioned or haloperidol-treated rats, whereas deletion of the NOP receptor gene conferred mice partial protection from haloperidol-induced motor depression. The antiparkinsonian action of NOP receptor antagonists was associated with reduction of glutamate release in the SN. In 6-hydroxydopamine hemilesioned rats, enhancement of N/OFQ expression and release was detected in the lesioned compared with the unlesioned SN, indicating that parkinsonism may be associated with overactivation of the N/OFQ-NOP receptor system in the SN. Finally, deletion of the N/OFQ gene conferred mice partial protection against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced loss of SN dopamine neurons. Based on these data, we propose that NOP receptor antagonists may represent a novel approach for combined (symptomatic and neuroprotective) therapy of Parkinson's disease.