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Gerald Zamponi

Mohamed Teleb, Fang-Xiong Zhang, Ahmed M Farghaly, Omaima M Aboul Wafa, Frank R Fronczek, Gerald W Zamponi, Hesham Fahmy
Cardiovascular diseases (CVDs) are the main cause of deaths worldwide. Up-to-date, hypertension is the most significant contributing factor to CVDs. Recent clinical studies recommend calcium channel blockers (CCBs) as effective treatment alone or in combination with other medications. Being the most clinically useful CCBs, 1,4-dihydropyridines (DHPs) attracted great interest in improving potency and selectivity. However, the short plasma half-life which may be attributed to the metabolic oxidation to the pyridine-counterparts is considered as a major limitation for this class...
April 3, 2017: European Journal of Medicinal Chemistry
Flavia R Silva, Artur S Miranda, Rebeca P M Santos, Isabella G Olmo, Gerald W Zamponi, Tomas Dobransky, Jader S Cruz, Luciene B Vieira, Fabiola M Ribeiro
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a polyglutamine expansion in the amino-terminal region of the huntingtin (htt) protein. In addition to facilitating neurodegeneration, mutant htt is implicated in HD-related alterations of neurotransmission. Previous data showed that htt can modulate N-type voltage-gated Ca(2+) channels (Cav2.2), which are essential for presynaptic neurotransmitter release. Thus, to elucidate the mechanism underlying mutant htt-mediated alterations in neurotransmission, we investigated how Cav2...
March 18, 2017: Neurobiology of Aging
Patrick Stemkowski, Agustin García-Caballero, Vinicius De Maria Gadotti, Said M'Dahoma, Shuo Huang, Stefanie Alice Gertrud Black, Lina Chen, Ivana Assis Souza, Zizhen Zhang, Gerald Werner Zamponi
No abstract text is available yet for this article.
February 28, 2017: Cell Reports
Do Young Kim, Fang-Xiong Zhang, Stan T Nakanishi, Timothy Mettler, Ik-Hyun Cho, Younghee Ahn, Florian Hiess, Lina Chen, Patrick G Sullivan, S R Wayne Chen, Gerald W Zamponi, Jong M Rho
OBJECTIVES: Carisbamate (CRS) is a novel monocarbamate compound that possesses antiseizure and neuroprotective properties. However, the mechanisms underlying these actions remain unclear. Here, we tested both direct and indirect effects of CRS on several cellular systems that regulate intracellular calcium concentration [Ca(2+) ]i . METHODS: We used a combination of cellular electrophysiologic techniques, as well as cell viability, Store Overload-Induced Calcium Release (SOICR), and mitochondrial functional assays to determine whether CRS might affect [Ca(2+) ]i levels through actions on the endoplasmic reticulum (ER), mitochondria, and/or T-type voltage-gated Ca(2+) channels...
April 2017: Epilepsia
Nicole E Burma, Robert P Bonin, Heather Leduc-Pessah, Corey Baimel, Zoe F Cairncross, Michael Mousseau, Jhenkruthi Vijaya Shankara, Patrick L Stemkowski, Dinara Baimoukhametova, Jaideep S Bains, Michael C Antle, Gerald W Zamponi, Catherine M Cahill, Stephanie L Borgland, Yves De Koninck, Tuan Trang
Opiates are essential for treating pain, but termination of opiate therapy can cause a debilitating withdrawal syndrome in chronic users. To alleviate or avoid the aversive symptoms of withdrawal, many of these individuals continue to use opiates. Withdrawal is therefore a key determinant of opiate use in dependent individuals, yet its underlying mechanisms are poorly understood and effective therapies are lacking. Here, we identify the pannexin-1 (Panx1) channel as a therapeutic target in opiate withdrawal...
March 2017: Nature Medicine
Patrick Stemkowski, Agustin García-Caballero, Vinicius De Maria Gadotti, Said M'Dahoma, Shuo Huang, Stefanie Alice Gertrud Black, Lina Chen, Ivana Assis Souza, Zizhen Zhang, Gerald Werner Zamponi
Peripheral nerve injury and tissue inflammation result in upregulation of the deubiquitinase USP5, thus causing a dysregulation of T-type calcium channel activity and increased pain sensitivity. Here, we have explored the role of afferent fiber activity in this process. Conditioning stimulation of optogenetically targeted cutaneous TRPV1 expressing nociceptors, but not that of non-nociceptive fibers, resulted in enhanced expression of USP5 in mouse dorsal root ganglia and spinal dorsal horn, along with decreased withdrawal thresholds for thermal and mechanical stimuli that abated after 24 hr...
December 13, 2016: Cell Reports
Arsalan P Rizwan, Xiaoqin Zhan, Gerald W Zamponi, Ray W Turner
Mossy fiber afferents to cerebellar granule cells form the primary synaptic relay into cerebellum, providing an ideal site to process signal inputs differentially. Mossy fiber input is known to exhibit a long-term potentiation (LTP) of synaptic efficacy through a combination of presynaptic and postsynaptic mechanisms. However, the specific postsynaptic mechanisms contributing to LTP of mossy fiber input is unknown. The current study tested the hypothesis that LTP induces a change in intrinsic membrane excitability of rat cerebellar granule cells through modification of Kv4 A-type potassium channels...
November 2, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Junting Huang, Gerald W Zamponi
Calcium entry via voltage gated calcium channels mediates a wide range of physiological functions, whereas calcium channel dysregulation has been associated with numerous pathophysiological conditions. There are myriad cell signaling pathways that act on voltage gated calcium channels to fine tune their activities and to regulate their cell surface expression. These regulatory mechanisms include the activation of G protein-coupled receptors and downstream phosphorylation events, and their control over calcium channel trafficking through direct physical interactions...
October 18, 2016: Current Opinion in Pharmacology
Emmanuel Bourinet, Gerald W Zamponi
Venoms from various predatory species, such as fish hunting mollusks scorpions, snakes and arachnids contain a large spectrum of toxins that include blockers of voltage-gated calcium channels. These peptide blockers act by two principal manners - physical occlusion of the pore and prevention of activation gating. Many of the calcium channel-blocking peptides have evolved to tightly occupy their binding pocket on the principal pore forming subunit of the channel, often rendering block poorly reversible. Moreover, several of the best characterized blocking peptides have developed a high degree of channel subtype selectivity...
October 15, 2016: Neuropharmacology
Joanna Lazniewska, Yuriy Rzhepetskyy, Fang-Xiong Zhang, Gerald W Zamponi, Norbert Weiss
T-type calcium channels are key contributors to neuronal physiology where they shape electrical activity of nerve cells and contribute to the release of neurotransmitters. Enhanced T-type channel expression has been causally linked to a number of pathological conditions including peripheral painful diabetic neuropathy. Recently, it was demonstrated that asparagine-linked glycosylation not only plays an essential role in regulating cell surface expression of Cav3.2 channels, but may also support glucose-dependent potentiation of T-type currents...
November 2016: Pflügers Archiv: European Journal of Physiology
Agustin Garcia-Caballero, Vinicius M Gadotti, Lina Chen, Gerald W Zamponi
BACKGROUND: Cav3.2 T-type calcium currents in primary afferents are enhanced in various painful pathological conditions, whereas inhibiting Cav3.2 activity or expression offers a strategy for combating the development of pain hypersensitivity. We have shown that Cav3.2 channel surface density is strongly regulated by the ubiquitination machinery and we identified the deubiquitinase USP5 as a Cav3.2 channel interacting protein and regulator of its cell surface expression. We also reported that USP5 is upregulated in chronic pain conditions...
2016: Molecular Pain
Zubaidha Pudukulatham, Fang-Xiong Zhang, Vinicius M Gadotti, Said M'Dahoma, Prabhuling Swami, Yasinalli Tamboli, Gerald W Zamponi
BACKGROUND: T-type calcium channels are important contributors to signaling in the primary afferent pain pathway and are thus important targets for the development of analgesics. It has been previously reported that certain piperazine-based compounds such as flunarizine are able to inhibit T-type calcium channels. Thus, we hypothesized that novel piperazine compounds could potentially act as analgesics. RESULTS: Here, we have created a series of 14 compound derivatives around a diphenyl methyl-piperazine core pharmacophore...
2016: Molecular Pain
Jing Fan, Patrick L Stemkowski, Maria A Gandini, Stefanie A Black, Zizhen Zhang, Ivana A Souza, Lina Chen, Gerald W Zamponi
Genetic ablation of cellular prion protein (PrP(C)) has been linked to increased neuronal excitability and synaptic activity in the hippocampus. We have previously shown that synaptic activity in hippocampi of PrP-null mice is increased due to enhanced N-methyl-D-aspartate receptor (NMDAR) function. Here, we focused on the effect of PRNP gene knock-out (KO) on intrinsic neuronal excitability, and in particular, the underlying ionic mechanism in hippocampal neurons cultured from P0 mouse pups. We found that the absence of PrP(C) profoundly affected the firing properties of cultured hippocampal neurons in the presence of synaptic blockers...
2016: Frontiers in Cellular Neuroscience
Awanish Mishra, Jasmine Kaur Punia, Chris Bladen, Gerald W Zamponi, Rajesh Kumar Goel
Piperine, a natural compound isolated from the fruits of Piper, is known to modulate several neurotransmitter systems such as serotonin, norepinephrine, and GABA, all of which have been linked to the development of convulsions. Fruits of Piper species have been suggested as means for managing seizure disorders. The present study was designed to elucidate the anticonvulsant effect of piperine and its mechanisms of action using in-silico, in-vivo and in-vitro techniques.PASS software was used to determine its possible activity and mechanisms...
2015: Channels
Gerald W Zamponi
Voltage-gated calcium channels are important regulators of brain, heart and muscle functions, and their dysfunction can give rise to pathophysiological conditions ranging from cardiovascular disorders to neurological and psychiatric conditions such as epilepsy, pain and autism. In the nervous system, calcium channel blockers have been used successfully to treat absence seizures, and are emerging as potential therapeutic avenues for pathologies such as pain, Parkinson disease, addiction and anxiety. This Review provides an overview of calcium channels as drug targets for nervous system disorders, and discusses potential challenges and opportunities for the development of new clinically effective calcium channel inhibitors...
January 2016: Nature Reviews. Drug Discovery
Gerald W Zamponi, Joerg Striessnig, Alexandra Koschak, Annette C Dolphin
Voltage-gated calcium channels are required for many key functions in the body. In this review, the different subtypes of voltage-gated calcium channels are described and their physiologic roles and pharmacology are outlined. We describe the current uses of drugs interacting with the different calcium channel subtypes and subunits, as well as specific areas in which there is strong potential for future drug development. Current therapeutic agents include drugs targeting L-type Ca(V)1.2 calcium channels, particularly 1,4-dihydropyridines, which are widely used in the treatment of hypertension...
October 2015: Pharmacological Reviews
Saïd M'Dahoma, Vinicius M Gadotti, Fang-Xiong Zhang, Byeongyeon Park, Ji Hye Nam, Valentina Onnis, Gianfranco Balboni, Jae Yeol Lee, Gerald W Zamponi
T-type channels are important contributors to the initiation and the maintenance of chronic pain states. Blocking T-type channels is therefore a possible therapeutic strategy for relieving pain. Here, we report the Cav3.2 T-type channel blocking action of a previously reported small organic molecule, KYS-05090S. This compound was able to reduce transiently expressed Cav3.2 currents with low micromolar affinity and mediated a hyperpolarizing shift in half-inactivation potential. KYS-05090S was then tested in models of acute and neuropathic pain...
February 2016: Pflügers Archiv: European Journal of Physiology
Vinicius M Gadotti, Chris Bladen, Fang Xiong Zhang, Lina Chen, Miyase Gözde Gündüz, Rahime Şimşek, Cihat Şafak, Gerald W Zamponi
Voltage-activated calcium channels are important facilitators of nociceptive transmission in the primary afferent pathway. Consequently, molecules that block these channels are of potential use as pain therapeutics. Our group has recently reported on the identification of a novel class of dihydropyridines (DHPs) that included compounds with preferential selectivity for T-type over L-type channels. Among those compounds, M4 was found to be an equipotent inhibitor of both Cav1.2 L- and Cav3.2 T-type calcium channels...
December 2015: Pflügers Archiv: European Journal of Physiology
Norbert Weiss, Gerald W Zamponi
No abstract text is available yet for this article.
September 2015: Journal of General Physiology
Zizhen Zhang, Vinicius M Gadotti, Lina Chen, Ivana A Souza, Patrick L Stemkowski, Gerald W Zamponi
Noxious stimuli are detected by peripheral nociceptors and then transmitted to higher CNS centers, where they are perceived as an unpleasant sensation. The mechanisms that govern the emotional component associated with pain are still incompletely understood. Here, we used optogenetic approaches both in vitro and in vivo to address this issue. We found that peripheral nerve injury inhibits pyramidal cell firing in the prelimbic area of the prefrontal cortex as a result of feed-forward inhibition mediated by parvalbumin-expressing GABAergic interneurons...
August 4, 2015: Cell Reports
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