nancy Osorio

Background and PurposeProtoxin II (ProTx II) is a high affinity gating modifier that is thought to selectively block the Nav1.7 voltage‐dependent Na+ channel, a major therapeutic target for the control of pain. We aimed at producing ProTx II analogues entitled with novel functionalities for cell distribution studies and biochemical characterization of its Nav channel targets.Experimental ApproachWe took advantage of the high affinity properties of the peptide, combined to its slow off rate, to design a number of new tagged analogues useful for imaging and biochemistry purposes. We used high‐throughput automated patch‐clamp to identify the analogues best matching the native properties of ProTx II and validated them on various Nav‐expressing cells in pull‐down and cell distribution studies.Key ResultsTwo of the produced ProTx II analogues, Biot‐ProTx II and ATTO488‐ProTx II, best emulate the pharmacological properties of unlabelled ProTx II, whereas other analogues remain high affinit...

The invention relates to the use of a sodium channel modulator Navl.9 in the treatment or prevention of an inflammatory skin disease. The invention also relates to a pharmaceutical composition comprising a modulator of the sodium channel Nav 1.9 and methods of in vitro diagnostics based on the detection or quantification of Nav 1.9.

The main objective of this study is to implement a ludic and pedagogical strategy aimed at boys and girls of kindergarten level, in order to strengthen the attention span in their learning process; for which, it was necessary to develop an investigation with a mixed approach, of descriptive type and with the application of the inductive method. Surveys for children, teachers and parents were designed; which yielded information that added to the non-structural observation made to the school, in its physical environment and the characteristics of the teachers; provided the necessary data to generate the guidelines for the design of the strategy. The kindergarten group was selected with a population and sample of nine students, four boys and five girls; resulting in the possibility of reducing the influence of noise in the internalization of knowledge and the attention span of the student through the use of a ludic and pedagogical strategy called "Triqui Magico

El objetivo de este trabajo es describir los servicios al ecosistema que ofrece la vegetación arvense asociada al cultivo de tomate. Se identificaron 58 especies dicotiledóneas pertenecientes a 22 familias. La colecta se realizó en diez fincas productoras de tomate industrial ubicadas en las comunidades de Tres Quebradas, La Limona, La Colorada, San Luis, La Balita, La Espigadilla, La Lomita y La Honda en el distrito de Los Santos, provincia de Los Santos. Los resultados indican que 30 especies (26%) ofrecen apoyo como fijadoras de nitrógeno, forrajeras y hábitat de polinizadores; 45 especies (39%) proveen alimento, energía y recursos genéticos; 31 especies (27%) son reguladoras del microclima y las patogénesis del cultivo y 9 especies (8%) ofrecen servicio cultural como ornamentales. Las especies registradas con mayor frecuencia absoluta y relativa son Rynchosia mínima y Calopogonium mucunoides (Fabaceae). En este escrito se describen los beneficios de las arvenses, sus potenciales...

Medication-overuse headaches (MOH) occur with both over-the-counter and pain-relief medicines, including paracetamol, opioids and combination analgesics. The mechanisms that lead to MOH are still uncertain. Here, we show that abnormal activation of Nav1.9 channels by Nitric Oxide (NO) is responsible for MOH induced by triptan migraine medicine. Deletion of the Scn11a gene in MOH mice abrogates NO-mediated symptoms, including cephalic and extracephalic allodynia, photophobia and phonophobia. NO strongly activates Nav1.9 in dural afferent neurons from MOH but not normal mice. Abnormal activation of Nav1.9 triggers CGRP secretion, causing artery dilatation and degranulation of mast cells. In turn, released mast cell mediators potentiates Nav1.9 in meningeal nociceptors, exacerbating inflammation and pain signal. Analysis of signaling networks indicates that PKA is downregulated in trigeminal neurons from MOH mice, relieving its inhibitory action on NO-Nav1.9 coupling. Thus, anomalous a...

En plus du courant sodium transitoire, responsable de la depolarisation rapide du potentiel d’action (PA), les canaux sodium dependants du potentiel generent deux courants sous-liminaires, les courants persistant et resurgent, actives pour des potentiels plus negatifs que le seuil du PA. Dans les cellules en grain du cervelet (CGC), nous avons cherche a etablir quelles etaient la localisation subcellulaire et les sousunites Nav1 constitutives des canaux ioniques a l’origine de ces courants. Les CGC sont de petits neurones glutamatergiques du cortex cerebelleux qui possedent une activite electrique complexe. In vivo, les CGC peuvent soutenir des trains de PA a des frequences maximales de 200 Hz en reponse a des stimulations sensorielles. Ces neurones peuvent aussi repondre par des bouffees de PA pour des stimulations liminaires in situ et in vivo. Des simulations de l'electrogenese dans les CGC ont suggere l’intervention des trois composantes, precedemment citees, du courant sodium, sans donnees experimentales precises. Nous avons montre que les CGC en culture expriment les sous-unites Nav1. 2 et Nav1. 6. Exprimees en meme temps, ces sous-unites occupent neanmoins des localisations subcellulaires differentes, dependantes de la maturation des segments initiaux (SI). Seule Nav1. 2 est concentree aux SI precoces alors que Nav1. 6 est dispersee tout au long du neurone. Au cours de la maturation, Nav1. 6 s’accumule progressivement aux SI et se retouve ainsi concentre avec Nav1. 2. Ce schema de developpement des SI est similaire a celui que nous avons observe in situ. Par la methode du sodium inverse, nous avons determine les parametres biophysiques du courant sodium transitoire et montre l’existence d’un courant sodium persistant. Des perfusions locales de TTX nous ont permis de determiner une origine majoritairement neuritique de ce courant persistant. Enfin, nous avons montre la presence d’un courant sodium resurgent dans les CGC en culture. Parce que Nav1. 6 est une sous-unite particulierement importante dans les systemes neuronaux matures, nous avons tenter de cerner sa fonction dans les CGC. Pour cela, nous avons utilise deux modeles de souris : des souris med (Nav1. 6-/-) qui ne survivent pas au-dela de trois semaines et des souris dont le gene Scn8a (codant pour Nav1. 6) a ete inactive uniquement dans les CGC (Scn8a CGC KO). Dans les CGC med en culture, en l'absence de Nav1. 6, le courant sodium transitoire, en plus d'etre tres reduit, est plus susceptible a l'inactivation lente, c'est-a-dire qu'au potentiel de repos, moins de canaux sont disponibles pour emettre un PA. Le courant resurgent est fortement diminue alors que le courant persistant n’est pas modifie. La capacite des CGC en culture a emettre des trains de PA en reponse a des depolarisations soutenues est alors fortement perturbee, et ces neurones n'emettent plus qu'un ou deux PA. In situ, sur des tranches de souris Scn8a CGC KO adultes, la disparition de Nav1. 6 affecte moderement les decharges a hautes frequences. Cette difference peut etre expliquee par une presence encore importante de Nav1. 2 aux SI a P60, mais elle suggere egalement un mecanisme de genese des PA different de celui observe en culture. Nos resultats suggerent neanmoins une contribution majeure de Nav1. 6 dans l’electrogenese des CGC de souris adultes. Elle pourrait etre confirmee par une etude sur des souris Scn8a CGC KO plus âgees chez lesquelles un deficit d'apprentissage au rotarod a ete montre.

The intrinsic primary afferent neurons (IPANs) of the guinea pig enteric nervous system express Nav1.9 sodium channels that produce a persistent TTX‐resistant current having a low activation threshold and slow gating kinetics. These neurons receive slow EPSPs induced mainly by the activation of neurokinin 3 receptors (NK3r). Here, we demonstrate that senktide, a specific NK3r agonist, potentiates the Nav1.9 current (INav1.9) in IPANs. Using whole‐cell patch‐clamp recordings from IPANs in duodenum longitudinal muscle/myenteric plexus preparations, we show that short (1–5 s) and long (up to 1 min) applications of senktide, increase the INav1.9 peak current up to 13‐fold. The effect, blocked by a NK3r antagonist SB235375 is transient, lasting ∼2 min and is due to a negative shift of the activation voltage by ∼20 mV and of fast inactivation by ∼10 mV. As a consequence, the window current resulting from the product of the activation and fast inactivation curves is shifted and enlarged. T...

The ion channel dynamics that underlie the complex firing patterns of cerebellar granule (CG) cells are still largely unknown. Here, we have characterized the subcellular localization and functional properties of Na+ channels that regulate the excitability of CG cells in culture. As evidenced by RT‐PCR and immunocytochemical analysis, morphologically differentiated CG cells expressed Nav1.2 and Nav1.6, though both subunits appeared to be differentially regulated. Nav1.2 was localized at most axon initial segments (AIS) of CG cells from 8 days in vitro DIV 8 to DIV 15. At DIV 8, Nav1.6 was found uniformly throughout somata, dendrites and axons with occasional clustering in a subset of AIS. Accumulation of Nav1.6 at most AIS was evident by DIV 13–14, suggesting it is developmentally regulated at AIS. The specific contribution of these differentially distributed Na+ channels has been assessed using a combination of methods that allowed discrimination between functionally compartmentali...

Voltage-gated sodium (Nav) channels play a central role in gastrointestinal physiology because they transmit depolarizing impulses in enteric neurons, thereby enabling the coordination of intestinal motility. However, little is known about the ion channel machinery that specifies firing pattern of enteric neurons. Here, we usedin situpatch-clamp recording of myenteric neurons from mice to define functionally the Nav channel subtypes responsible for the electrical signature of myenteric neurons. We found that mouse myenteric neurons exhibit two types of tetrodotoxin-resistant Na+currents: an early inactivating Na+current (INaT) and a persistent Na+current (INaP).INaTwas encountered in all myenteric neurons, whereasINaPwas preferentially found in Dogiel type II sensory neurons. Knock-out mouse studies, in combination with pharmacological assays, indicate thatINaTis carried by theScn5a-encoded “cardiac” Nav1.5, whereasINaPis attributed to theScn11a-encoded Nav1.9. Current-clamp experim...

We recorded from myenteric AH/Dogiel type II cells, demonstrated mechanosensitive responses, and characterized their basic properties. Recordings were obtained using the mouse longitudinal muscle myenteric plexus preparation with patch-clamp and sharp intracellular electrodes. The neurons had an action potential hump and a slow afterhyperpolarization (AHP) current. The slow AHP was carried by intermediate conductance Ca2+-dependent K+-channel currents sensitive to charybdotoxin and clotrimazole. All possessed a hyperpolarization-activated current that was blocked by extracellular cesium. They also expressed a TTX-resistant Na+ current with an onset near the resting potential. Pressing on the ganglion containing the patched neuron evoked depolarizing potentials in 17/18 cells. The potentials persisted after synaptic transmission was blocked. Volleys of presynaptic electrical stimuli evoked slow excitatory postsynaptic potentials (EPSPs) in 9/11 sensory neurons, but 0/29 cells receive...

Enteric neurons located in the gastro-intestinal tract are of particular importance to control digestive functions such as motility and secretion. In our recent publication, we showed that mouse myenteric neurons exhibit 2 types of tetrodotoxin-resistant Na(+) currents: a fast inactivating Na(+) current produced by Nav1.5 channels, present in nearly all myenteric neurons, and a persistent Na(+) current attributed to Nav1.9 channels, restricted to the intrinsic primary afferent neurons (IPANs). By combination of experimental recording and computer simulation we found that Nav1.5 contributed to the upstroke velocity of action potentials (APs), whereas Nav1.9 opposed AP repolarization. Here, we detailed the Na(+), Ca(2+) and K(+) currents used in our computational model of IPAN. We refined the prototype cell to reproduce the sustained firing pattern recorded in situ. As shown in experimental conditions we demonstrated that Nav1.9 channels critically determine the up-state life-time and...