Agradecemos a Sarah Wu y Camille Graham para el desarrollo de las primeras fases del ensayo enfriado sonda, el Centro de Bloomington Drosophila para poblaciones de moscas, y los miembros del laboratorio Galko para la lectura crítica del manuscrito. Este trabajo fue apoyado por el NIH NRSA (NIH F31NS083306) a HNT, y por el NIH R01NS069828, R21NS087360 y una Universidad de Texas MD Anderson Clark Fellowship en Investigación Básica a MJG.

1. Preparación de las larvas <ol><li> Elevar acciones o cruces genéticos en una incubadora a 25 ºC. <ol><li> Si el cultivo de una cruz, utilizar 20-25 hembras vírgenes y 15-20 varones por cada vial que contiene medios de comunicación regular de mosca harina de maíz. Permitir que las hembras ponen huevos a aproximadamente 48 h antes de transferirlos a un nuevo vial de alimentos. </li></ol></li><li> 4-5 días después de la puesta de huevos, recoger 3 rd instar larvas del genotipo deseado por chorros suavemente una corriente de agua en la comida blanda y larvas, y verter el contenido en una, placa de Petri limpia de tamaño mediano (60 mm x 15 mm). </li><li> A continuación, ordenar suavemente larvas por tamaño usando fórceps o un pincel para impedir más grande &quot;errante 3 rd instar&quot; o larvas enfermizo pequeña de ser probado. larvas de Descarte contiene ningún marcadores genéticos no deseadas o equilibradores. </li><li> Tener un compañero de platos de etiquetas miembro del laboratorio o recipientes donde se colocará larvas ordenados de modo que el experimentador puede ser &quot;ciegos&quot; a la experimental condición o genotipo de las larvas en su caso. El experimentador puede aplicar etiquetas decodificadas a los datos recogidos después de que el experimento utilizando una clave generada por un laboratorio-miembro. </li><li> El uso de un scoopula, transferir una cantidad tamaño de una moneda de alimentos frescos en una (35 mm x 10 mm o 60 mm x 15 mm) limpio, placa de Petri etiquetada lleno hasta la mitad con agua a temperatura ambiente. </li><li> mover suavemente el larvas ordenados sobre el alimento (para evitar la inanición o desecación si se anticipa pruebas que tomar más de 20 min) usando fórceps o pincel. </li></ol> 2. Fría ensayo de sondas <ol><li> A su vez en la unidad de sonda fría permitiendo unos pocos minutos para que se enfríe a la temperatura deseada. Si el ajuste a temperaturas más bajas, la condensación es probable que formar a lo largo de la sonda. </li><li> Limpiar cualquier exceso de humedad con un laboratorio de toallita antes de la aplicación a la larva. Cuando no está en uso inmediato, el lugar de aislamiento tapa de la sonda a la vez aislar y mantener la punta limpia y evitar daños. </li><li> Colocar un 3 rd instar larva mediados sobre una pieza delgada de vinilo movible oscuro (típicamente, utilice un pequeño trozo cortado de un aglutinante notebook) bajo un microscopio de campo brillante. Las ayudas de vinilo negros en la visualización de contraste y en mover la larva sin tocarlo para alinearlo correctamente con la sonda. </li><li> Ajuste el microscopio (véase la Tabla de Materiales) y la unidad de luz (véase la Tabla de Materiales) a brillo medio (50-75% de brillo max) para proporcionar contraste y evitar que la larva se seque demasiado rápido. </li><li> Descarte cualquier larva que no exhiben primera locomoción peristáltica normal, ya que podrían confundir los resultados. La larva debe estar húmedo de la placa de Petri de agua de lo contrario la larva se adherirá a la de vinilo inhibir la locomoción normal. El agua no debe formar un charco alrededor de la larva. </li><li> Avanzar en la sonda con la mano hacia la larva en un ángulo de 90º con respecto al eje anteroposterior del cuerpo, utilizando el vinilo para mover la larva en corposición rect (véase la Figura 1A). </li><li> Oriente la punta de la sonda para sentar suavemente por la superficie dorsal media de la larva con la sonda en un ángulo de aproximadamente 45º a la platina del microscopio. </li><li> Tras el contacto de la sonda, iniciar un temporizador de laboratorio. Aplicar suficiente presión hacia abajo para sangrar ligeramente la superficie de la cutícula larval mientras que todavía permite adelante o movimiento hacia atrás. </li><li> Mantener la sonda en su lugar durante un máximo de 10 s o hasta que se observó una respuesta de comportamiento evocada por el frío - lo que ocurra primero. A continuación, retire la sonda. </li><li> Registrar la respuesta conductual observada y la latencia de respuesta. Las larvas que no responde dentro de 10 s se consideran &quot;no respondedores&quot;. Latencia también se puede grabar para los respondedores y se usa para medir los cambios en respuesta robustez / amplitud. </li><li> Descartar larva y preparar el siguiente. </li><li> Repetir los pasos 2.3 a 2.11 hasta que se alcanza el número deseado de larvas de prueba (tres conjuntos de n = 20-40 larvas fueron used aquí). </li></ol>

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Una solicitud de patente de Estados Unidos (CL) está pendiente en el diseño de la sonda fría. Información adicional sobre los detalles de los números de pieza sonda fría y la construcción, así como la consulta adicional sobre el diseño de la herramienta se puede proporcionar a petición.

El ensayo descrito aquí se puede utilizar para evaluar cualitativa y cuantitativamente la nocicepción o sensibilización nociceptiva en larvas de varios fondos genéticos, influencias ambientales, y / o condiciones de avería inducida. Dado que este ensayo permite la aplicación focal de un estímulo frío, con esta herramienta se puede evaluar la función de un subconjunto de neuronas sensoriales periféricas específicamente en respuesta a las temperaturas frías. Curiosamente, estos comportamientos evocados fríos ...

Drosophila ha demostrado ser de gran utilidad para la identificación de nuevos genes conservados y circuitos neuronales que subyacen a los comportamientos complejos. Moscas proporcionan un conjunto de herramientas genético sofisticado y un sistema nervioso simplificado, que permiten la manipulación precisa genética y neuronal 1, 2, 3, 4 para diseccionar las bases celulares y moleculares de la nocicepción 5, 6, 7. Las larvas son particularmente útiles para estos análisis, dado que los ensayos de comportamiento para el tacto suave 8, 9, 10, calor nocivo 11, 12, 13 y la sensación mecánica de estímulos nocivos 4, </sup&gt; 11 ya se han establecido, y la cutícula larval transparente permite la obtención de imágenes en vivo o fijo de la epidermis y de las neuronas sensoriales subyacentes. Recientemente, un ensayo frío nocivo También se ha desarrollado 7, que se describe con más detalle aquí. Usando una sonda fría bien,-cónica con punta, mostramos que exhiben las larvas de Drosophila un conjunto de comportamientos reactivos específicos de frío, distinto de comportamientos observados durante la locomoción normal, siguientes toque suave, o después de duras estímulos mecánico de temperatura o alta 7, 8, 11 . Los comportamientos específicos de frío incluyen un robusto contracción de todo el cuerpo (CT), un aumento de 45-90º de los segmentos posteriores (PR) y un aumento simultáneo de la parte anterior y posterior segmentos en forma de U (Estados Unidos). La prevalencia de estos comportamientos se incrementa con temperaturas decrecientes pero cada picos a sligeramente diferentes temperaturas frías. Trabajos recientes sugieren que las respuestas de TC están mediadas por diferentes neuronas sensoriales periféricas que los que responden a estímulos calor nocivo o mecánica dura 7. Al igual que los nociceptores vertebrados, Drosophila dendríticas múltiple (MD), las neuronas sensoriales periféricas tienen estructuras dendríticas complejos que ramifican sobre la epidermis 1. neuronas MD están presentes en cada segmento del cuerpo de las larvas, la proyección de sus axones al cordón nervioso ventral 14. neuronas sensoriales MD están separados en cuatro clases diferentes (I-IV) en base a la morfología dendrítica y tienen diferentes funciones sensoriales 4, 9, 10, 15, 16, 17. Si bien se requieren neuronas clase IV para las respuestas de balanceo de la carrocería lateral de larvasa altas temperaturas o estímulos mecánicos dura 4, clase III se requieren las neuronas para las respuestas de suave tacto 9, 10 y no sólo se activan por frío, pero también son necesarios para las respuestas de comportamiento evocada por frío 7. Ambos de clase III y clase IV neuronas utilizan potenciales canales discretos receptor transitorio (TRP) para facilitar las respuestas de comportamiento a nociva 7, 11, 18 y no nocivo estímulos 9, 10, 17, 19. Además, la nocicepción larval se sensibiliza después de la lesión, en los niveles celular 20 y de comportamiento 12, 21. El ensayo descrito aquí permite la quantification de cualquiera normal, o potencialmente alteró las respuestas de comportamiento a bajas temperaturas que van desde nocivo frío (≤ 10 ºC), enfriar inocuo (11-17 ºC), a temperatura ambiente (18-22 ºC). Las temperaturas frías utilizadas en este ensayo son capaces de activar directamente de clase III neuronas sensoriales, provocando robustos, los aumentos de calcio reproducibles y respuestas de comportamiento evocada por frío, que puede ser cualitativa y cuantitativamente analizadas 7. Este ensayo puede ser aplicado a larvas de virtualmente cualquier genotipo, así como a las larvas expuestas a diversas condiciones ambientales (nutrición alterado, lesión, agentes farmacológicos) para determinar los factores tanto genéticos como ambientales que afectan a la nocicepción frío, sensibilización nociceptiva o plasticidad nociceptivo. Dado que thermosensation es ubicuo en muchas especies, este ensayo proporciona una herramienta valiosa para el estudio de la nocicepción y puede descubrir nuevas dianas de genes o interacciones neuronales que mejorennuestra comprensión de la nocicepción vertebrados. La sonda fría hecha a la medida (ver sonda fría, Tabla de Materiales) utiliza una temperatura de bucle cerrado controlado dispositivo Peltier, que enfría el tubo de aluminio y punta cónica a través de la conducción térmica. Un termistor está incorporado dentro de la punta cónica de aluminio informa de la temperatura en tiempo real sobre la unidad de control. Un disipador de calor y el ventilador están unidos al módulo termoeléctrico para regular la carga del efecto Peltier calor (Qc) de modo que el intervalo de temperatura deseado de (22-0 ° C) se puede lograr (véase la unidad de control térmico, Tabla de Materiales). El estímulo frío nocivo de la punta de sonda fría se aplica a mano a la línea media dorsal, a segmento (s) equidistante de los extremos anterior y posterior (aproximadamente segmento A4, véase la Figura 1A) de la larva. En respuesta a estímulos de frío, las larvas generalmente producen uno de los tres comportamientos evocados frías dentro de un 10 s de corte: un cuerpo llenocontracción (TC), un aumento de 45-90º segmentos anterior y posterior en forma de U (Estados Unidos), o un aumento de los segmentos posteriores (PR) (descritos en los resultados). Ninguno de estos comportamientos se llevan a cabo durante la locomoción peristáltica normal o comportamiento de forrajeo. Estos comportamientos también son distintas de las respuestas táctiles suaves y la respuesta aversiva rodadura a alta temperatura o estímulos mecánicos nocivos.

<table><tbody><tr><td>Cold Probe</td><td>Pro-Dev Engineering</td><td>Custom-built on demand</td><td>Part numbers and construction details can be provided on request</td></tr><tr><td>Thermal Control Unit</td><td>TE Technology</td><td>Custom Built enclosure</td><td>Part numbers and construction details can be provided on request</td></tr><tr><td>Zeiss Stemi 2000 microscope</td><td>Zeiss</td><td>NT55-605</td><td></td></tr><tr><td>Fiber-Lite MI-150 High Intensity Illuminator</td><td>Dolan-Jenner Industries.</td><td>A20500</td><td></td></tr><tr><td>Schott Dual Gooseneck 23 inch Fiber Optic Light Guide</td><td>Schott North America, Inc.</td><td>Schott A08575</td><td></td></tr><tr><td>Forceps</td><td>FST</td><td>FS-1670</td><td>Used to sort and handle larvae. Be sure to smooth and blunt forceps tips slightly to lower the risk of accidently puncturing or injuring the larvae</td></tr><tr><td>Paintbrush</td><td>Dick Blick Art Materials</td><td>06762-1002</td><td>Used to sort and handle larvae. It is helpful if the paintbrush is damp during use.</td></tr><tr><td>35 mm x 10 mm Polystyrene Petri dish</td><td>Falcon</td><td>351008</td><td></td></tr><tr><td>60mm x 10 mm Polystyrene Petri dish</td><td>Falcon</td><td>351007</td><td></td></tr><tr><td>Piece of black vinyl (at least 2 inches x 2 inches)</td><td></td><td></td><td>Used to provide contrast and orient larvae to the cold probe</td></tr><tr><td>Fisherbrand Scoopula Spatula</td><td>Fisher Scientific</td><td>14-357Q</td><td>Used to move food</td></tr><tr><td>Kimtech Science Kimwipes</td><td>Fisher Scientific</td><td>06-666A</td><td>Used to dry the larvae and cold probe if there is excess moisture</td></tr></tbody></table>

novel assay for cold nociception in drosophila larvae

Cómo los organismos detectar y responder a las temperaturas nocivas aún es poco conocido. Además, los mecanismos de sensibilización de la maquinaria sensorial, tal como en los pacientes que experimentan la neuropatía periférica o sensibilización inducida por la lesión subyacentes, no están bien caracterizados. El modelo de Drosophila genéticamente tratables se ha utilizado para estudiar las células y los genes necesarios para la detección de calor nocivo, que ha dado múltiples genes conservados de interés. Poco se sabe sin embargo sobre las células y los receptores importantes para la detección frío nocivo. Aunque, Drosophila no sobrevive a la exposición prolongada a temperaturas frías (≤10 ºC), y evitará fresco, prefiriendo las temperaturas más cálidas en ensayos de preferencias de comportamiento, cómo se detectan y, posiblemente, evitar estímulos de frío nocivos sólo recientemente ha sido investigado. Aquí se describen y caracterizan los primeros fríos nocivo (≤10 ºC) en el ensayo de conductaDrosophila. El uso de esta herramienta y el ensayo, se muestra un investigador cómo evaluar cualitativa y cuantitativamente comportamientos nociceptivos fríos. Esto puede hacerse en condiciones de cultivo normales / sanos, o presumiblemente en el contexto de una enfermedad, lesión o sensibilización. Además, este ensayo puede ser aplicado a larvas seleccionadas para los genotipos deseados, lo que podría impactar thermosensation, dolor, o sensibilización nociceptiva. Dado que el dolor es un proceso altamente conservada, utilizando este ensayo para estudiar más a fondo la nocicepción térmica es probable que recoger importante comprensión de los procesos de dolor en otras especies, incluyendo vertebrados.

Drosophila larvas se mueven con un movimiento peristáltico que incluye pausas ocasionales, cabeza vueltas, y los cambios de dirección 22. En respuesta a la aplicación focal de un estímulo nocivo frío sin embargo, las larvas presentan un conjunto de comportamientos únicos, a diferencia del rodillo lateral aversivo al calor nocivo y estímulos mecánicos. Estos comportamientos también son diferentes de las respuestas al toque suave ...

Watch this Scientific Journal Video about Novel Assay for Cold Nociception in Drosophila Larvae at JoVE.com

Novel Assay for Cold Nociception in Drosophila Larvae

Aquí se demuestra un nuevo ensayo para estudiar la nocicepción frío en larvas de Drosophila. Este ensayo utiliza una sonda Peltier hecha a la medida capaz de aplicar un estímulo frío nocivo focal y da lugar a comportamientos específicos de frío cuantificables. Esta técnica permitirá además disección celular y molecular de la nocicepción frío.

Ensayo novedoso para la nocicepción en frío<em&gt; Drosophila</em&gt; Las larvas

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory ...

novel-assay-for-cold-nociception-in-drosophila-larvae

Research

JoVE Journal

Neuroscience

Novel Assay for Cold Nociception in Drosophila Larvae

7.7K vistas.  UT MD Anderson Cancer Center.  Aquí se demuestra un nuevo ensayo para estudiar la nocicepción frío en larvas de Drosophila. Este ensayo utiliza una sonda Peltier hecha a la medida capaz de aplicar un estímulo frío nocivo focal y da lugar a comportamientos específicos de frío cuantificables. Esta técnica permitirá además disección celular y molecular de la nocicepción frío. 

Video: Novel Assay for Cold Nociception in Drosophila Larvae

Local and Global Methods of Assessing Thermal Nociception in Drosophila Larvae

In this article, we demonstrate assays to study thermal nociception in Drosophila larvae. One assay involves spatially-restricted (local) stimulation of thermal nociceptors1,2 while the second involves a wholesale (global) activation of most or all such neurons3. Together, these techniques allow visualization and quantification of the behavioral functions of Drosophila nociceptive sensory neurons.
The Drosophila larva is an established model system to study thermal nociception, a sensory response to potentially harmful temperatures that is evolutionarily conserved across species1,2. The advantages of Drosophila for such studies are the relative simplicity of its nervous system and the sophistication of the genetic techniques that can be used to dissect the molecular basis of the underlying biology4-6 In Drosophila, as in all metazoans, the response to noxious thermal stimuli generally involves a "nocifensive" aversive withdrawal to the presented stimulus7. Such stimuli are detected through free nerve endings or nociceptors and the amplitude of the organismal response depends on the number of nociceptors receiving the noxious stimulus8. In Drosophila, it is the class IV dendritic arborization sensory neurons that detect noxious thermal and mechanical stimuli9 in addition to their recently discovered role as photoreceptors10. These neurons, which have been very well studied at the developmental level, arborize over the barrier epidermal sheet and make contacts with nearly all epidermal cells11,12. The single axon of each class IV neuron projects into the ventral nerve cord of the central nervous system11 where they may connect to second-order neurons that project to the brain.
Under baseline conditions, nociceptive sensory neurons will not fire until a relatively high threshold is reached. The assays described here allow the investigator to quantify baseline behavioral responses or, presumably, the sensitization that ensues following tissue damage. Each assay provokes distinct but related locomotory behavioral responses to noxious thermal stimuli and permits the researcher to visualize and quantify various aspects of thermal nociception in Drosophila larvae. The assays can be applied to larvae of desired genotypes or to larvae raised under different environmental conditions that might impact nociception. Since thermal nociception is conserved across species, the findings gleaned from genetic dissection in Drosophila will likely inform our understanding of thermal nociception in other species, including vertebrates.

Local and Global Methods of Assessing Thermal Nociception in Drosophila Larvae

In this article, we demonstrate assays to study thermal nociception in Drosophila larvae. One assay involves spatially-restricted (local) stimulation of thermal nociceptors1,2 while the second involves a wholesale (global) activation of most or all such neurons3. Together, these techniques allow visualization and quantification of the behavioral functions of Drosophila nociceptive sensory neurons.

Métodos locales y globales de evaluación de nocicepción térmica en<em&gt; Drosophila</em&gt; Las larvas

In this article, we demonstrate assays to study thermal nociception in Drosophila larvae. One assay involves spatially-restricted (local) stimulation of ...

Investigación

Neurociencias

Visualization of Proprioceptors in Drosophila Larvae and Pupae

Proprioception is the ability to sense the motion, or position, of body parts by responding to stimuli arising within the body. In fruitflies and other insects proprioception is provided by specialized sensory organs termed chordotonal organs (ChOs) 2. Like many other organs in Drosophila, ChOs develop twice during the life cycle of the fly. First, the larval ChOs develop during embryogenesis. Then, the adult ChOs start to develop in the larval imaginal discs and continue to differentiate during metamorphosis.
The development of larval ChOs during embryogenesis has been studied extensively 10,11,13,15,16. The centerpiece of each ChO is a sensory unit composed of a neuron and a scolopale cell. The sensory unit is stretched between two types of accessory cells that attach to the cuticle via specialized epidermal attachment cells 1,9,14. When a fly larva moves, the relative displacement of the epidermal attachment cells leads to stretching of the sensory unit and consequent opening of specific transient receptor potential vanilloid (TRPV) channels at the outer segment of the dendrite 8,12. The elicited signal is then transferred to the locomotor central pattern generator circuit in the central nervous system.
Multiple ChOs have been described in the adult fly 7. These are located near the joints of the adult fly appendages (legs, wings and halters) and in the thorax and abdomen. In addition, several hundreds of ChOs collectively form the Johnston's organ in the adult antenna that transduce acoustic to mechanical energy 3,5,17,4.
In contrast to the extensive knowledge about the development of ChOs in embryonic stages, very little is known about the morphology of these organs during larval stages. Moreover, with the exception of femoral ChOs 18 and Johnston's organ, our knowledge about the development and structure of ChOs in the adult fly is very fragmentary.
Here we describe a method for staining and visualizing ChOs in third instar larvae and pupae. This method can be applied together with genetic tools to better characterize the morphology and understand the development of the various ChOs in the fly.

Visualization of Proprioceptors in Drosophila Larvae and Pupae

A method to immunostain and visualize chordotonal organs in larvae and pupae of Drosophila melanogaster is described.

Visualización de los propioceptores<em&gt; Drosophila</em&gt; Las larvas y pupas

Proprioception is the ability to sense the motion, or position, of body parts by responding to stimuli arising within the body. In fruitflies and other ...

Novel Whole-tissue Quantitative Assay of Nitric Oxide Levels in Drosophila Neuroinflammatory Response

Neuroinflammation is a complex innate immune response vital to the healthy function of the central nervous system (CNS). Under normal conditions, an intricate network of inducers, detectors, and activators rapidly responds to neuron damage, infection or other immune infractions. This inflammation of immune cells is intimately associated with the pathology of neurodegenerative disorders, such as Parkinson&#39;s disease (PD), Alzheimer&#39;s disease and ALS. Under compromised disease states, chronic inflammation, intended to minimize neuron damage, may lead to an over-excitation of the immune cells, ultimately resulting in the exacerbation of disease progression. For example, loss of dopaminergic neurons in the midbrain, a hallmark of PD, is accelerated by the excessive activation of the inflammatory response. Though the cause of PD is largely unknown, exposure to environmental toxins has been implicated in the onset of sporadic cases. The herbicide paraquat, for example, has been shown to induce Parkinsonian-like pathology in several animal models, including Drosophila melanogaster. Here, we have used the conserved innate immune response in Drosophila to develop an assay capable of detecting varying levels of nitric oxide, a cell-signaling molecule critical to the activation of the inflammatory response cascade and targeted neuron death. Using paraquat-induced neuronal damage, we assess the impact of these immune insults on neuroinflammatory stimulation through the use of a novel, quantitative assay. Whole brains are fully extracted from flies either exposed to neurotoxins or of genotypes that elevate susceptibility to neurodegeneration then incubated in cell-culture media. Then, using the principles of the Griess reagent reaction, we are able to detect minor changes in the secretion of nitric oxide into cell-culture media, essentially creating a primary live-tissue model in a simple procedure. The utility of this model is amplified by the robust genetic and molecular complexity of Drosophila melanogaster, and this assay can be modified to be applicable to other Drosophila tissues or even other small, whole-organism inflammation models.

Novel Whole-tissue Quantitative Assay of Nitric Oxide Levels in Drosophila Neuroinflammatory Response

Levels of the inflammatory cell-signaling molecule nitric oxide (NO) are commonly assayed using Griess reagent. In this protocol, we have created a modified Griess assay utilizing live Drosophila brain tissue in order to detect the secretion of NO in a simple, quantifiable and highly repeatable method.

Neuroinflammation is a complex innate immune response vital to the healthy function of the central nervous system (CNS). Under normal conditions, an ...

Inmunología e Infección

Appetitive Associative Olfactory Learning in Drosophila Larvae

In the following we describe the methodological details of appetitive associative olfactory learning in Drosophila larvae. The setup, in combination with genetic interference, provides a handle to analyze the neuronal and molecular fundamentals of specifically associative learning in a simple larval brain.
Organisms can use past experience to adjust present behavior. Such acquisition of behavioral potential can be defined as learning, and the physical bases of these potentials as memory traces1-4. Neuroscientists try to understand how these processes are organized in terms of molecular and neuronal changes in the brain by using a variety of methods in model organisms ranging from insects to vertebrates5,6. For such endeavors it is helpful to use model systems that are simple and experimentally accessible. The Drosophila larva has turned out to satisfy these demands based on the availability of robust behavioral assays, the existence of a variety of transgenic techniques and the elementary organization of the nervous system comprising only about 10,000 neurons (albeit with some concessions: cognitive limitations, few behavioral options, and richness of experience questionable)7-10.
Drosophila larvae can form associations between odors and appetitive gustatory reinforcement like sugar11-14. In a standard assay, established in the lab of B. Gerber, animals receive a two-odor reciprocal training: A first group of larvae is exposed to an odor A together with a gustatory reinforcer (sugar reward) and is subsequently exposed to an odor B without reinforcement 9. Meanwhile a second group of larvae receives reciprocal training while experiencing odor A without reinforcement and subsequently being exposed to odor B with reinforcement (sugar reward). In the following both groups are tested for their preference between the two odors. Relatively higher preferences for the rewarded odor reflect associative learning - presented as a performance index (PI). The conclusion regarding the associative nature of the performance index is compelling, because apart from the contingency between odors and tastants, other parameters, such as odor and reward exposure, passage of time and handling do not differ between the two groups9.

Appetitive Associative Olfactory Learning in Drosophila Larvae

Drosophila larvae are able to associate odor stimuli with gustatory reward. Here we describe a simple behavioral paradigm that allows the analysis of appetitive associative olfactory learning.

Apetitivo aprendizaje asociativo olfativa en<em&gt; Drosophila</em&gt; Las larvas

In the following we describe the methodological  details of appetitive associative olfactory learning in Drosophila larvae. The setup, in combination with ...

Light Preference Assay to Study Innate and Circadian Regulated Photobehavior in Drosophila Larvae

Light acts as environmental signal to control animal behavior at various levels. The Drosophila larval nervous system is used as a unique model to answer basic questions on how light information is processed and shared between rapid and circadian behaviors. Drosophila larvae display a stereotypical avoidance behavior when exposed to light. To investigate light dependent behaviors comparably simple light-dark preference tests can be applied. In vertebrates and arthropods the neural pathways involved in sensing and processing visual inputs partially overlap with those processing photic circadian information. The fascinating question of how the light sensing system and the circadian system interact to keep behavioral outputs coordinated remains largely unexplored. Drosophila is an impacting biological model to approach these questions, due to a small number of neurons in the brain and the availability of genetic tools for neuronal manipulation. The presented light-dark preference assay allows the investigation of a range of visual behaviors including circadian control of phototaxis.

Light Preference Assay to Study Innate and Circadian Regulated Photobehavior in Drosophila Larvae

Here we describe a light-dark preference test for Drosophila larva. This assay provides information about innate and circadian regulation of light sensing and processing photobehavior.

Ensayo Preferencia luz para estudiar innata y circadiano Photobehavior Regulado de<em&gt; Drosophila</em&gt; Las larvas

Light acts as environmental signal to control animal behavior at various levels. The Drosophila larval nervous system is used as a unique model to answer ...

A Single-fly Assay for Foraging Behavior in Drosophila

For many animals, hunger promotes changes in the olfactory system in a manner that facilitates the search for appropriate food sources. In this video article, we describe an automated assay to measure the effect of hunger or satiety on olfactory dependent food search behavior in the adult fruit fly Drosophila melanogaster. In a light-tight box illuminated by red light that is invisible to fruit flies, a camera linked to custom data acquisition software monitors the position of six flies simultaneously. Each fly is confined to walk in individual arenas containing a food odor at the center. The testing arenas rest on a porous floor that functions to prevent odor accumulation. Latency to locate the odor source, a metric that reflects olfactory sensitivity under different physiological states, is determined by software analysis. Here, we discuss the critical mechanics of running this behavioral paradigm and cover specific issues regarding fly loading, odor contamination, assay temperature, data quality, and statistical analysis.

A Single-fly Assay for Foraging Behavior in Drosophila

In this video article, we describe an automated assay to measure the effect of hunger or satiety on olfactory dependent food search behavior in the adult fruit fly Drosophila melanogaster.

Un ensayo de una sola mosca por el comportamiento de forrajeo en<em&gt; Drosophila</em

For many animals, hunger promotes changes in the olfactory system in a manner that facilitates the search for appropriate food sources. In this video ...

An Improved Assay and Tools for Measuring Mechanical Nociception in Drosophila Larvae

Published assays for mechanical nociception in Drosophila have led to variable assessments of behavior. Here, we fabricated, for use with Drosophila larvae, customized metal nickel-titanium alloy (nitinol) filaments. These mechanical probes are similar to the von Frey filaments used in vertebrates to measure mechanical nociception. Here, we demonstrate how to make and calibrate these mechanical probes and how to generate a full behavioral dose-response from subthreshold (innocuous or non-noxious range) to suprathreshold (low to high noxious range) stimuli. To demonstrate the utility of the probes, we investigated tissue damage-induced hypersensitivity in Drosophila larvae. Mechanical allodynia (hypersensitivity to a normally innocuous mechanical stimulus) and hyperalgesia (exaggerated responsiveness to a noxious mechanical stimulus) have not yet been established in Drosophila larvae. Using mechanical probes that are normally innocuous or probes that typically elicit an aversive behavior, we found that Drosophila larvae develop mechanical hypersensitization (both allodynia and hyperalgesia) after tissue damage. Thus, the mechanical probes and assay that we illustrate here will likely be important tools to dissect the fundamental molecular/genetic mechanisms of mechanical hypersensitivity.

An Improved Assay and Tools for Measuring Mechanical Nociception in Drosophila Larvae

The goal of this protocol is to show how to perform an improved assay for mechanical nociception in Drosophila larvae. We use the assay here to demonstrate that mechanical hypersensitivity (allodynia and hyperalgesia) exists in Drosophila larvae.

Un ensayo mejorado y herramientas para medir la nocicepción mecánica en larvas de Drosophila

Published assays for mechanical nociception in Drosophila have led to variable assessments of behavior. Here, we fabricated, for use with Drosophila ...

Comportamiento

A Temperature Gradient Assay to Determine Thermal Preferences of Drosophila Larvae

Many animals, including the fruit fly, Drosophila melanogaster, are capable of discriminating minute differences in&#160;environmental temperature, which enables them to seek out their preferred thermal landscape. To define the temperature preferences of larvae over a defined linear range, we developed an assay using a temperature gradient. To establish a single-directional gradient, two aluminum blocks are connected to independent water baths, each of which controls the temperature of individual blocks. The two blocks set the lower and upper limits of the gradient. The temperature gradient is established by placing an agarose-coated aluminum plate over the two water-controlled blocks so that the plate spans the distance between them. The ends of the aluminum plate that is set on the top of the water blocks defines the minimum and maximum temperatures, and the regions in-between the two blocks form a linear temperature gradient. The gradient assay can be applied to&#160;larvae of different ages and can be used to identify mutants that exhibit phenotypes, such as those with mutations affecting genes encoding TRP channels and opsins, which are required for temperature discrimination.

A Temperature Gradient Assay to Determine Thermal Preferences of Drosophila Larvae

Here, we present a protocol to determine the preferred environmental temperature of Drosophila larvae using a continuous thermal gradient.

Un análisis de gradiente de temperatura para determinar las preferencias térmicas de larvas de Drosophila

Many animals, including the fruit fly, Drosophila melanogaster, are capable of discriminating minute differences in&#160;environmental temperature, which ...

Behavioral Assays for Optogenetic Manipulation of Neural Circuits in Drosophila melanogaster

Optogenetics has become a fundamental technique in neuroscience, enabling precise control of neuronal activity through light stimulation. This study introduces easy-to-implement setups for applying optogenetic methods in Drosophila melanogaster. Two optogenetic tools, CsChrimson, a red-light-activated cation channel, and GtACR2, a blue-light-activated anion channel, were employed in four experimental approaches. Three of these approaches involve single-fly experiments: (1) a blue-light optogenetic thermotactic positional preference assay targeting temperature-sensitive heating cells, (2) a red-light optogenetic positional preference assay activating bitter sensing neurons, and (3) a proboscis extension response assay activating the sweet-sensing neurons. The fourth approach (4) is a fly maze setup to assess avoidance behaviors using multiple flies. The ability to manipulate neural activity temporally and spatially offers powerful insights into sensory processing and decision-making, underscoring the potential of optogenetics to advance our knowledge of neural function. These methods provide an accessible and robust framework for future research in neuroscience to enhance the understanding of specific neural pathways and their behavioral outcomes.

This paper presents methods for optogenetic manipulation in Drosophila melanogaster, utilizing CsChrimson and GtACR2 to activate and silence specific neurons. Four experiments are described to utilize optogenetics to explore thermotactic and gustatory behaviors, providing insights into the underlying neural mechanisms governing these processes.

Ensayos conductuales para la manipulación optogenética de circuitos neuronales en Drosophila melanogaster

Optogenetics has become a fundamental technique in neuroscience, enabling precise control of neuronal activity through light stimulation. This study ...

Local Heat Probe Assay: A Method to Assess Nociception of High Temperatures in Drosophila Larvae

Source: Chattopadhyay, A., et al. <a href="https://www.jove.com/video/3837/" target="_blank">Local and Global Methods of Assessing Thermal Nociception in Drosophila Larvae</a>. J. Vis. Exp. (2012).
Drosophila larvae have dedicated sensory neurons&#8211;nociceptors&#8211;whose response to potentially harmful thermal stimuli triggers aversive&#8211;or so-called &#34;nocifensive&#34;&#8211;behaviors in the animal. This video describes a method to assess thermal nociception by recording larval behavior in response to local application of a heat probe onto the cuticle. This method is, therefore, called the local heat probe assay.

Ensayo de sonda de calor local: un método para evaluar la nocicepción de altas temperaturas en larvas de Drosophila

Source: Chattopadhyay, A., et al. Local and Global Methods of Assessing Thermal Nociception in Drosophila Larvae. J. Vis. Exp. (2012).
Drosophila larvae ...

Ensayo novedoso para la nocicepción en frío

Resumen

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