Nana Voitenko

Bogomolets Institute of Physiology NASU · Laboratory of Sensory Signalling

The development of pain symptoms in peripheral diabetic neuropathy (PDN) is associated with the upregulation of T-type Ca2+ channels (T-channels) in the soma of nociceptive DRG neurons. Moreover, a block of these channels in DRG neurons effectively reversed mechanical and thermal hyperalgesia in animal diabetic models, indicating that T-channel fun...

• Spared nerve injury (SNI) altered the action potential (AP) output of lamina I spino-parabrachial neurons (SPNs) without affecting their resting potential or membrane resistance.• In one-third of SPNs, high-threshold dorsal root stimulation elicited persistent AP firing which was never observed in cells from naïve animals.• 38% of SPNs from SNI r...

The dorsal horn (DH) neurons of the spinal cord play a critical role in nociceptive input integration and processing in the central nervous system. Engaged neuronal classes and cell-specific excitability shape nociceptive computation within the DH. The DH hyperexcitability (central sensitisation) has been considered a fundamental mechanism in media...

Although spinal processing of sensory information greatly relies on afferent-driven (AD) presynaptic inhibition (PI), our knowledge about how it shapes peripheral input to different types of nociceptive neurons remains insufficient. Here we examined the AD-PI of primary afferent input to spinal neurons in the marginal layer, lamina I, and the layer...

Motor disability is a common outcome of spinal cord injury (SCI). The recovery of motor function after injury depends on the severity of neurotrauma; motor deficit can be reversible, at least partially, due to the innate tissue capability to recover, which, however, deteriorates with age. Pain is often a comorbidity of injury, although its predicti...

Despite being involved in a number of functions, such as nociception and locomotion, spinal lamina X remains one of the least studied central nervous system regions. Here, we show that Aδ- and C-afferent inputs to lamina X neurons are presynaptically inhibited by homo- and heterosegmental afferents as well as by descending fibers from the corticosp...

restoration of the spinal cord function presents a most severe biomedical issue nowadays. The aim of the study was to detect the macroporous poly(N-[2-hydroxypropyl]-methacrylamide hydrogel (PHPMA-hydrogel, HG) restorative effect dependence on the severity of the laceration spinal cord injury in young organisms. The male rats sample (~1-month-old,...

The activity-dependent trafficking of AMPA receptors (AMPAR) mediates synaptic strength and plasticity, while the perturbed trafficking of the receptors of different subunit compositions has been linked to memory impairment and to causing neuropathology. In the spinal cord, nociceptive-induced changes in AMPAR trafficking determine the central sens...

Pre- and postsynaptic inhibition of spinal lamina I neurons play an important role in the spinal nociceptive processing. Although the low-threshold fibers are believed to mediate both types of inhibition, their role in shaping responses of lamina I neurons is poorly understood. Here, we did patch-clamp recording from lamina I neurons and simultaneo...

Numerous investigations implicate pronounced changes in the functioning of T-type Ca2+ channels localized on the somata of primary nociceptor units in the development and maintenance of painful diabetic neuropathy. This review highlights the role of T-type Ca2+ channels of nociceptive afferents in the processing of pain signals under diabetic condi...

Lamina I spino-parabrachial neurons (SPNs) receive peripheral nociceptive input, process it and transmit to the supraspinal centres. Although responses of SPNs to cutaneous receptive field stimulations have been intensively studied, the mechanisms of signal processing in these neurons are poorly understood. Therefore, we used an ex-vivo spinal cord...

Traumatic brain injury (TBI) results from severe or mild damage to the brain tissue from accidents or assaults. TBI often leads to impaired motor functions, amnesia, and cognitive dysfunctions, which dramatically reduces the quality of life, and societal productivity of TBI patients. As a result of TBI, neurons in the original damage area “spill” g...

Spinal lamina I neurons receive inputs from nociceptive Aδ- and C-fiber afferents and relay these inputs to the supraspinal pain processing centers. Pre- and postsynaptic inhibition of these neurons play an important role in processing of painful stimuli. Although the low-threshold fibers are believed to mediate both types of inhibition, their role...

The spinal gray matter region around the central canal, lamina X, is critically involved in somatosensory processing and visceral nociception. Although several classes of primary afferent fibers terminate or decussate in this area, little is known about organization and functional significance of the afferent supply of lamina X neurons. Using the h...

Upregulation of Ca2+-permeable AMPA receptors (CP-AMPARs) in dorsal horn (DH) neurons has been causally linked to persistent inflammatory pain. This upregulation, demonstrated for both synaptic and extrasynaptic AMPARs, depends on the protein kinase C alpha (PKCα) activation; hence, spinal PKC inhibition has alleviated peripheral nociceptive hypers...

Persistent pain remains a major health issue: common treatments relying on either repeated local injections or systemic drug administration are prone to concomitant side-effects. It is thought that an alternative could be a multifunctional cargo system to deliver medicine to the target site and release it over a prolonged time window. We nano-engin...

The hippocampus is the most susceptible region of the brain to ischemic lesion, with highly vulnerable pyramidal interneurons to ischemic cell death. A restricted brain neurogenesis limits a withdrawal of massive cell death after stroke that endorses cell-based therapies for neuronal replacement strategies following cerebral ischemia. Neurons diffe...

Spasticity, a common complication after spinal cord injury (SCI), is frequently accompanied by chronic pain. The physiological origin of this pain (critical to its treatment) remains unknown, although spastic motor dysfunction has been related to the hyperexcitability of motoneurons and to changes in spinal sensory processing. Here we show that the...

Spino-cerebral (projection) neurons localized in lamina I of the spinal gray substance play an important role in the transmission of pain-related information to the brain. We examined spontaneous excitatory postsynaptic currents (sEPSC) recorded from lamina I spino-pontine neurons in isolated preparations of the rat lumbar spinal cord; the respecti...

Functional properties of lamina X neurons in the spinal cord remain unknown despite the established role of this area for somatosensory integration, visceral nociception, autonomic regulation and motoneuron output modulation. Investigations of neuronal functioning in the lamina X have been hampered by technical challenges. Here we introduce an ex-v...

Organotypic cultures of the spinal cord possess significant advantages, as compared with routine cell systems in vitro; the cytoarchitectonics, cytospecificity of the cells, cell-to-cell connections, and other characteristics of spinal cord tissues are preserved to a considerable extent. We analyzed structural/functional characteristics of organoty...

Among all the brain, the hippocampus is the most susceptible region to ischemic lesion, with the highest vulnerability of CA1 pyramidal neurons to ischemic damage. This damage may cause either prompt neuronal death (within hours) or with a delayed appearance (over days), providing a window for applying potential therapies to reduce or prevent ische...

Background A growing body of evidence suggests that ATP-gated P2X3 receptors (P2X3Rs) are implicated in chronic pain. We address the possibility that stable, synthetic analogs of diadenosine tetraphosphate (Ap4A) might induce antinociceptive effects by inhibiting P2X3Rs in peripheral sensory neurons. Results The effects of two stable, synthetic Ap...

Pyramidal neurons of the hippocampus possess differential susceptibility to the ischemia-induced damage with the highest vulnerability of CA1 and the lower sensitivity of CA3 neurons. This damage is triggered by Ca2+-dependent excitotoxicity and can result in a delayed cell death that might be potentially suspended through activation of endogenous...

Upregulation of Ca2+-permeable AMPA receptors (CP-AMPARs) in the dorsal horn neurons of the spinal cord has been causally linked to the maintenance of persistent inflammatory pain. Therefore, inhibition of CP-AMPARs could potentially alleviate an, otherwise, poorly treatable chronic pain. However, a loss of CP-AMPARs could produce considerable side...

Previous studies have shown that increased excitability of capsaicin-sensitive DRG neurons and thermal hyperalgesia in rats with short-term (2-4 weeks) streptozotocin-induced diabetes is mediated by upregulation of T-type Ca(2+) current. In longer-term diabetes (after the 8th week) thermal hyperalgesia is changed to hypoalgesia that is accompanied...

Persistent peripheral inflammation alters trafficking of AMPA receptors (AMPARs) at the synapses between primary afferents and dorsal horn (DH) neurons that contributes to the maintenance of inflammatory pain. However, whether peripheral inflammation changes the synaptic activity within the DH circuitry and how it modulates synaptic AMPARs in diffe...

This review describes the features of the systems to ensure the restoration of calcium homeostasis of hippocampal neurons during ischemic injury. High levels of intracellular Ca 2+ , glutamate excitotoxicity activity and the formation of free radicals during ischemia are a major damaging factors, leading to further damage to hippocampal neurons. Un...

T-type Ca(2+) channels are known as important participants of nociception and their remodeling contributes to diabetes-induced alterations of pain sensation. In this work we have established that about 30% of rat nonpeptidergic thermal C-type nociceptive (NTCN) neurons of segments L4-L6 express a slow T-type Ca(2+) current (T-current) while a fast...

Unlabelled: Persistent inflammation promotes internalization of synaptic GluR2-containing, Ca(2+)-impermeable AMPA receptors (AMPARs) and insertion of GluR1-containing, Ca(2+)-permeable AMPARs at extrasynaptic sites in dorsal horn neurons. Previously we have shown that internalization of synaptic GluR2-containing AMPARs requires activation of spin...

Streptozotocin (STZ)-induced type 1 diabetes in rats leads to the development of peripheral diabetic neuropathy (PDN) manifested as thermal hyperalgesia at early stages (4th week) followed by hypoalgesia after 8 weeks of diabetes development. Here we found that 6-7 week STZ-diabetic rats developed either thermal hyper- (18%), hypo- (25%) or normalg...

Ionotropic purine P2X receptors play important roles in the processes of generation and transmission of nociceptive signals. The relative roles of certain subtypes of these receptors in the above processes have not, however, been finally elucidated. To a significant extent, this is explained by the absence of selective modulators of their functioni...

Persistent peripheral inflammation changes AMPA receptor (AMPAR) trafficking in dorsal horn neurons by promoting internalization of GluR2-containing, Ca(2+)-impermeable AMPARs from the synapses and by increasing insertion of GluR1-containing, Ca(2+)-permeable AMPARs in extrasynaptic plasma membrane. These changes contribute to the maintenance of pe...

Cannabinoid receptors (CBRs) belong to the G protein-coupled receptor superfamily, and activation of CBRs in salivary cells inhibits agonist-stimulated salivation and modifies saliva content. However, the role of different CBR subtypes in acinar cell physiology and in intracellular signalling remains unclear. Here, we uncover functional CB(1)Rs and...

Peripheral inflammation alters AMPA receptor (AMPAR) subunit trafficking and increases AMPAR Ca(2+) permeability at synapses of spinal dorsal horn neurons. However, it is unclear whether AMPAR trafficking at extrasynaptic sites of these neurons also changes under persistent inflammatory pain conditions. Using patch-clamp recording combined with Ca(...

The salivary acinar cells have unique Ca(2+) signaling machinery that ensures an extensive secretion. The agonist-induced secretion is governed by Ca(2+) signals originated from the endoplasmic reticulum (ER) followed by a store-operated Ca(2+) entry (SOCE). During tasting and chewing food a frequency of parasympathetic stimulation increases up to...

P2X3 purinoreceptors expressed in mammalian sensory neurons play a key role in several processes, including pain perception. From the venom of the Central Asian spider Geolycosa sp., we have isolated a novel peptide, named purotoxin-1 (PT1), which is to our knowledge the first natural molecule exerting powerful and selective inhibitory action on P2...

It has recently been shown that antinociceptive tolerance develops by repeated systemic administration of non-steroidal anti-inflammatory drugs (NSAIDs) metamizol and lysine-acetylsalicylate. This is similar to the tolerance observed with opioid-induced analgesia [Vanegas and Tortorici, 2002, Cell and Mol. Neurobiol. 22, 655-661]. In the present st...

Xerostomia is a troublesome complication of diabetes mellitus associated with decreased salivation. Previously we showed the diabetes-induced alterations of ACh-mediated [Ca2+]cyt signaling in submandibular salivary gland which provides a major secretion of fluid and electrolytes. Since salivation is initiated by an InsP3-mediated Ca2+ release from...

Spinal cord GluR2-lacking AMPA receptors (AMPARs) contribute to nociceptive hypersensitivity in persistent pain, but the molecular mechanisms underlying this event are not completely understood. We report that complete Freund's adjuvant (CFA)-induced peripheral inflammation induces synaptic GluR2 internalization in dorsal horn neurons during the ma...

Agonist stimulation of exocrine cells leads to the generation of intracellular Ca2+ signals driven by inositol 1,4,5-trisphosphate receptors (IP3Rs) that rapidly become global due to propagation throughout the cell. In many types of excitable cells the intracellular Ca2+ signal is propagated by a mechanism of Ca2+-induced Ca2+ release (CICR), media...

Ryanodine receptors (RyRs) play a key role in the generalization and spreading of calcium waves in excitable cells; however, the question of the existence of functionally active RyRs in nonexcitable cells demonstrating the capacity for exocytosis (e.g., salivary gland acini) remains open. We studied changes in the total amount of calcium stored in...

1. The pathogenesis of diabetic neuropathy is a complex phenomenon, the mechanisms of which are not fully understood. Our previous studies have shown that the intracellular calcium signaling is impaired in primary and secondary nociceptive neurons in rats with streptozotocin (STZ)-induced diabetes. Here, we investigated the effect of prolonged trea...

Calcium dynamics in the endoplasmic reticulum of dorsal root ganglion neurons of rats during Ca2+ release induced by caffeine and subsequent Ca2+ uptake were studied. Calcium release is shown to include two (a short transient and a prolonged slow) phases. We suggest that the transient phase reflects release of free Ca from the calcium store, while...

Xerostomia and pathological thirst are troublesome complications of diabetes mellitus associated with impaired functioning of salivary glands; however, their cellular mechanisms are not yet determined. Isolated acinar cells were loaded with Ca2+ indicators fura-2/AM for measuring cytosolic Ca2+ concentration ([Ca2+]i) or mag-fura-2/AM-inside the en...

In the acinar cells of rat submandibular salivary gland activation of cholinoreceptors leads to the release of Ca2+ from endoplasmic reticulum (ER). This Ca2+ release from ER is mainly mediated by InsP3-receptors. In the present work we used Arsenazo III dye and mag-fura 2/AM to measure total cellular calcium content and Ca2+ concentration in the E...

Functional kainate receptors are expressed in the spinal cord substantia gelatinosa region, and their activation contributes to bi-directional regulation of excitatory synaptic transmission at primary afferent synapses with spinal cord substantia gelatinosa neurons. However, no study has reported a role(s) for kainate receptor subtypes in long-term...

To study changes in the cytoplasmic Ca2+ concentration ([Ca2+]i) and the total amount of calcium in cells, we used, respectively, the fluorescent dye fura 2/AM and the metallochrome dye arsenazo III. The total amount of calcium in acinar cells after their incubation in calcium-free ATP-containing extracellular solution decreased. The action of ATP...

A comparative analysis of two models of nociceptive and neuropathic pain in rodents, carrageenan peripheral inflammation of soft tissues and streptozotocin-induced diabetic neuropathy, is presented in the review. Modern concepts on the pathways of transmission of pain information are analyzed. A few aspects of possible involvement at calcium signal...

Acinar cells of rat submandibular salivary gland are characterized by heterogeneity of intracellular Ca2+ stores. In the present work we have studied this heterogeneity using Arsenazo III dye to measure a cellular total calcium content and Fura-2/AM, to determine free cytosolic calcium concentration ([Ca2+]i). We have found that the amount of Ca2+...

In the resting state, the Ca2+ concentration in agonist-sensitive intracellular stores reflects the balance between active uptake of Ca2+, which is mediated by Ca2+-ATPase (SERCA), and passive leakage of Ca2+. The mechanisms underlying such a leakage in cells of the submaxillary salivary gland were not studied. In our experiments, we examined possi...

It is well-known that pH changes can influence a lot of cellular processes. In this work, we have specifically studied the influence of alkalinization, which can be developed in spinal cord neurons during hyperventilation (respiratory alkalosis) and chronic renal failure (metabolic alkalosis) on calcium homeostasis. Application of Tyrode solution w...