Our current understanding of insect phototransduction is based on a small number species, but insects occupy many different visual environments. We created the retinal transcriptome nocturnal insect, cockroach, Periplaneta americana to identify proteins involved in earliest stages compound eye phototransduction, and test hypothesis that environments are reflected molecular contributions function. assembled five novel mRNAs: two green opsins, one UV opsin, each TRP TRPL ion channel homologs....

Octopamine is a chemical relative of noradrenaline providing analogous neurohumoral control diverse invertebrate physiological processes. There also evidence for direct octopaminergic innervation some insect peripheral tissues. Here, we show that spider mechanoreceptors are innervated by octopamine-containing efferents. The mechanosensory neurons have octopamine receptors colocalized with synapsin labeling in the efferent fibers. In addition, enhances electrical response sensory to...

Höger, Ulli, Päivi H. Torkkeli, Ernst-August Seyfarth, and Andrew S. French. Ionic selectivity of mechanically activated channels in spider mechanoreceptor neurons. J. Neurophysiol. 78: 2079–2085, 1997. The lyriform slit-sense organ on the patella spider, Cupiennius salei, consists seven or eight slits, with each slit innervated by a pair sensitive Mechanotransduction is believed to occur at tips dendrites, which are surrounded Na + -rich receptor lymph. We studied ionic basis sensory...

Abstract Spider mechanosensory neurons receive an extensive network of efferent synapses onto their sensory dendrites, somata and distal axonal regions. The function these is unknown. Peripheral are also found on crustacean stretch‐receptor but not afferents other species, although inhibitory GABAergic a common feature centrally located axon terminals. Here we investigated the effects GABA receptor agonists antagonists one group spider neurons, slit sense organ VS‐3, which accessible to...

The spider VS-3 slit-sense organ contains two types of primary mechanoreceptor neurons that are morphologically similar but have different electrical behavior. Type A fire only one or action potentials in response to a mechanical step any amplitude above the threshold, whereas type B prolonged bursts stimuli. Voltage-clamp studies shown voltage-activated ion currents, noninactivating potassium current and an inactivating sodium current, dominate firing We simulated behavior neuron types,...

G-protein-coupled octopamine (OA) receptors mediate their effects by Ca2+ signaling or adjusting intracellular cAMP levels. Depending on OA concentration and cell type, activation of in excitable cells triggers excitatory inhibitory effects, but the mechanisms which mediates these are not well understood. We investigated that potentially activated OA, excitability frequency sensitivity mechanosensory neurons innervating VS-3 slit sensilla patella spider Cupiennius salei. These directly...

We studied the properties of voltage-activated outward currents in two types spider cuticular mechanoreceptor neurons to learn if these contribute differences their adaptation properties. Both adapt rapidly sustained stimuli, but type A usually only fire one or action potentials, whereas B can bursts lasting several hundred milliseconds. found that both had current components, 1) a transient activated when stimulated from resting potential and inactivated with maintained stimuli 2)...

Low-voltage-activated Ca 2+ currents (LVA- I ) are believed to perform several roles in neurons such as lowering the threshold for action potentials, promoting burst firing and oscillatory behavior, enhancing synaptic excitation. They also may allow rapid increases intracellular concentration. We discovered LVA- both members of paired mechanoreceptor a spider, where one neuron adapts rapidly (Type A) other slowly B) response step stimulus. To learn if contributed difference adaptation we...

gamma-Aminobutyric acid type A (GABA(A)) receptor activation inhibits many primary afferent neurons by depolarization and increased membrane conductance. Deterministic (step sinusoidal) functions are commonly used as stimuli to test such inhibition. We found that when the VS-3 mechanosensory innervating spider lyriform slit-sense organ were stimulated randomly varying white-noise mechanical or electrical signals, their responses GABA(A) agonists more complex than inhibition observed during...

Abstract Calcium ions play important roles in the adaptation of auditory hair cells, and there is evidence that they are involved modifying sensitivity a variety vertebrate invertebrate mechanoreceptors. However, little direct concerning concentration changes, signaling pathways or ultimate effects these proposed modulatory mechanisms. We measured receptor potential, current action potentials intracellularly during mechanotransduction group sensory neurons spider Cupiennius salei , which...

We measured frequency response functions between concentrations of fruit odorants and individual action potentials in large basiconic sensilla the Drosophila melanogaster antenna. A new method randomly varying odorant concentration was combined with rapid, continuous measurement at antenna by a miniature photoionization detector. All responses decreased progressively frequencies approaching 100 Hz, providing an upper limit for dynamics olfaction. found two distinct patterns: excitatory...

Invertebrates possess a diverse collection of pentameric Cys-loop ligand gated ion channel (LGIC) receptors whose molecular structures, evolution and relationships to mammalian counterparts have been intensely investigated in several clinically agriculturally important species. These are targets for variety control agents that may also harm beneficial However, little is known about spiders, which natural predators insects. We assembled de novo transcriptomes from the central peripheral...

The mechanosensilla in spider exoskeleton are innervated by bipolar neurons with their cell bodies close to the cuticle and dendrites attached it. Numerous efferent fibers synapse peripheral parts of mechanosensory neurons, glial cells surrounding each other. Most these immunoreactive γ-aminobutyric acid (GABA), sensory respond agonists ionotropic GABA receptors a rapid complete inhibition. In contrast, little is known about metabotropic B that may mediate long-term effects. We investigated...

Voltage-activated sodium current ( I Na ) is primarily responsible for the leading edge of action potential in many neurons. While generally activates rapidly when a neuron depolarized, its inactivation properties differ significantly between different neurons and even within one neuron, where often has slowly inactivating components. been suggested to regulate firing frequency some cells, but no clear picture this relationship emerged. We studied both members paired mechanosensory spider...

GABA and glutamate receptors belonging to the ligand-gated chloride-channel family are primary targets of insecticides antiparasitics, so their molecular structure, pharmacology biophysical properties have attracted significant attention. However, little is known about physiological roles these channels or how they regulate neuronal excitability animal behavior. Mechanosensory neurons VS-3 slit sensilla in patella tropical wandering spider, Cupiennius salei, react GABA(A)-receptor agonists,...

Abstract Most mechanosensory neurons are inhibited by GABAergic efferent neurons. This inhibition is often presynaptic and mediated ionotropic GABA receptors at the axon terminals. receptor activation opens Cl – channels, leading to membrane depolarization an increase in conductance. In many invertebrate preparations, that innervate afferents contain glutamate addition GABA, suggesting sensory also modulated glutamate. However, effects of on these not well understood. Peripheral parts spider...