The potential subunits involved in two subtypes of α-Bgt-resistant nAChRs in cockroach dorsal unpaired median (DUM) neurons

2017 ◽  
Vol 81 ◽  
pp. 32-40 ◽  
Author(s):  
Huahua Sun ◽  
Yang Liu ◽  
Jian Li ◽  
Xinzhu Cang ◽  
Haibo Bao ◽  
...  
Keyword(s):  
Dum Neurons ◽  
Dorsal Unpaired Median

scholarly journals Cys-Loop Ligand-Gated Chloride Channels in Dorsal Unpaired Median Neurons of Locusta migratoria

2010 ◽  
Vol 103 (5) ◽  
pp. 2587-2598 ◽  
Author(s):  
Daniel Janssen ◽  
Christian Derst ◽  
Jean-Michel Rigo ◽  
Emmy Van Kerkhove
Keyword(s):  
Gaba Receptors ◽  
Chloride Channels ◽  
Locusta Migratoria ◽  
Ibotenic Acid ◽  
Ionic Currents ◽  
Sequencing Analysis ◽  
Anion Channels ◽  
Continuous Application ◽  
Dum Neurons ◽  
Dorsal Unpaired Median

In insects, inhibitory neurotransmission is generally associated with members of the cys-loop ligand-gated anion channels, such as the glutamate-gated chloride channel (GluCl), the GABA-gated chloride channels (GABACl), and the histamine-gated chloride channels (HisCl). These ionotropic receptors are considered established target sites for the development of insecticides, and therefore it is necessary to obtain a better insight in their distribution, structure, and functional properties. Here, by combining electrophysiology and molecular biology techniques, we identified and characterized GluCl, GABACl, and HisCl in dorsal unpaired median (DUM) neurons of Locust migratoria. In whole cell patch-clamp recordings, application of glutamate, GABA, or histamine induced rapidly activating ionic currents. GluCls were sensitive to ibotenic acid and blocked by picrotoxin and fipronil. The pharmacological profile of the L. migratoria GABACl fitted neither the vertebrate GABAA nor GABAC receptor and was similar to the properties of the cloned Drosophila melanogaster GABA receptor subunit (Rdl). The expression of Rdl-like subunit-containing GABA receptors was shown at the molecular level using RT-PCR. Sequencing analysis indicated that the orthologous GABACl of D. melanogaster CG10357-A is expressed in DUM neurons of L. migratoria. Histamine-induced currents exhibited a fast onset and desensitized completely on continuous application of histamine. In conclusion, within the DUM neurons of L. migratoria, we identified three different cys-loop ligand-gated anion channels that use GABA, glutamate, or histamine as their neurotransmitter.

Coupling of Efferent Neuromodulatory Neurons to Rhythmical Leg Motor Activity in the Locust

1998 ◽  
Vol 79 (1) ◽  
pp. 361-370 ◽  
Author(s):  
Sylvie Baudoux ◽  
Carsten Duch ◽  
Oliver T. Morris
Keyword(s):  
Motor Activity ◽  
Motor Neurons ◽  
Spike Activity ◽  
Motor Pattern ◽  
Rhythmic Activity ◽  
Motor Output ◽  
Variable Activity ◽  
Metathoracic Ganglion ◽  
Dum Neurons ◽  
Dorsal Unpaired Median

Baudoux, Sylvie, Carsten Duch, and Oliver T. Morris. Coupling of efferent neuromodulatory neurons to rhythmical leg motor activity in the locust. J. Neurophysiol. 79: 361–370, 1998. The spike activity of neuromodulatory dorsal unpaired median (DUM) neurons was analyzed during a pilocarpine-induced motor pattern in the locust. Paired intracellular recordings were made from these octopaminergic neurons during rhythmic activity in hindleg motor neurons evoked by applying pilocarpine to an isolated metathoracic ganglion. This motor pattern is characterized by two alternating phases: a levator phase, during which levator, flexor, and common inhibitor motor neurons spike, and a depressor phase, during which depressor and extensor motor neurons spike. Three different subpopulations of efferent DUM neurons could be distinguished during this rhythmical motor pattern according to their characteristic spike output. DUM 1 neurons, which in the intact animal do not innervate muscles involved in leg movements, showed no change apart from a general increase in spike frequency. DUM 3 and DUM 3,4 neurons produced the most variable activity but received frequent and sometimes pronounced hyperpolarizations that were often common to both recorded neurons. DUM 5 and DUM 3,4,5 neurons innervate muscles of the hindleg and showed rhythmical excitation leading to bursts of spikes during rhythmic activity of the motor neurons, which innervate these same muscles. Sometimes the motor output was coordinated across both sides of the ganglion so that there was alternating activity between levators of both sides. In these cases, the spikes of DUM 5 and DUM 3,4,5 neurons and the hyperpolarization of DUM 3 and DUM 3,4 neurons occurred at particular phases in the motor pattern. Our data demonstrate a central coupling of specific types of DUM neurons to a rhythmical motor pattern. Changes in the spike output of these particular efferent DUM neurons parallel changes in the motor output. The spike activity of DUM neurons thus may be controlled by the same circuits that determine the action of the motor neurons. Functional implications for real walking are discussed.

Action of locust neuromodulatory neurons is coupled to specific motor patterns

1995 ◽  
Vol 74 (1) ◽  
pp. 347-357 ◽  
Author(s):  
M. Burrows ◽  
H. J. Pfluger
Keyword(s):  
Motor Neurons ◽  
Motor Pattern ◽  
Intracellular Recordings ◽  
Flexor Muscle ◽  
Motor Patterns ◽  
Specific Subset ◽  
Metathoracic Ganglion ◽  
Flexor Muscles ◽  
Dum Neurons ◽  
Dorsal Unpaired Median

1. Many muscles of the locust are supplied by dorsal unpaired median neurons (DUM neurons) that release octopamine and alter the contractions caused by spikes in motor neurons. To determine when these neuromodulatory neurons are normally activated during behaviour, intracellular recordings were made simultaneously from them and from identified motor neurons during the specific motor pattern that underlies kicking. A kick consists of a rapid and powerful extension of the tibia of one or both hind legs that is produced by a defined motor pattern. Only 3 identified DUM neurons of the 20 in the metathoracic ganglion spike during a kick, and they supply muscles involved in generating the kick. Their spikes occur in a distinctive and repeatable pattern that is closely linked to the pattern of spikes in the flexor and extensor tibiae motor neurons. When the extensor and flexor muscles cocontract, these three DUM neurons produce a burst of spikes at frequencies that can rise to 25 Hz, and with the number of spikes (3-15) related to the duration of this phase of the motor pattern. The spikes stop when the flexor muscle is inhibited and therefore before the tibia is extended rapidly. The other DUM neurons which supply muscles that are not directly involved in kicking are either inhibited or spike only sporadically. 2. The activation of a specific subset of DUM neurons during kicking may thus be timed to influence the action of the muscles that participate in this movement and appear to be controlled by the same circuits that determine the actions of the participating motor neurons. These modulatory neurons thus have specific individual actions in the control of movement.

Octopamine modulates ionic currents and spiking in dorsal unpaired median (DUM) neurons

Neuroreport ◽  
1997 ◽  
Vol 8 (17) ◽  
pp. 3737-3741 ◽  
Author(s):  
Holger Achenbach ◽  
Christian Walther ◽  
Dieter Wicher
Keyword(s):  
Ionic Currents ◽  
Dum Neurons ◽  
Dorsal Unpaired Median

Ca2+/Calmodulin-Dependent Protein Kinase Regulates GABA-Activated Cl− Current in Cockroach Dorsal Unpaired Median Neurons

2002 ◽  
Vol 87 (6) ◽  
pp. 2972-2982 ◽  
Author(s):  
Philippe Alix ◽  
Francoise Grolleau ◽  
Bernard Hue
Keyword(s):  
Protein Kinase ◽  
Cell Body ◽  
Gaba Receptors ◽  
Hill Coefficient ◽  
Dependent Protein Kinase ◽  
Logarithmic Curve ◽  
Neuron Cell Body ◽  
Dum Neurons ◽  
Dependent Protein ◽  
Dorsal Unpaired Median

We studied γ-aminobutyric acid (GABA)-mediated currents in short-term cultured dorsal unpaired median (DUM) neurons of cockroach Periplaneta americana using the whole cell patch-clamp technique in symmetrical chloride solutions. All DUM neurons voltage-clamped at −50 mV displayed inward currents ( I GABA) when 10−4 M of GABA was applied by pneumatic pressure-ejection pulses. The semi-logarithmic curve of I GABA amplitude versus the ejection time yielded a Hill coefficient of 4.0. I GABA was chloride (Cl−) because the reversal potential given by the current-voltage ( I-V) curve varied according to the value predicted by the Nernst equation for Cl−dependence. In addition, I GABA was almost completely blocked by bath application of the chloride channel blockers picrotoxin (PTX) or 3,3-bis(trifluoromethyl)bicyclo-[2,2,1]heptane-2,2-diacarbonitrile (BIDN). The I-V curve for I GABA displayed a unexpected biphasic aspect and was best fitted by two linear regressions giving two slope conductances of 35.6 ± 2.1 and 80.9 ± 4.1 nS for potentials ranging from 0 to −30 and −30 to −70 mV, respectively. At −50 mV, the current amplitude was decreased by cadmium chloride (CdCl2, 10−3 M) and calcium-free solution. The semi-logarithmic curve for CdCl2-resistant I GABA gave a Hill coefficient of 2.4. Hyperpolarizing voltage step from −50 to −80 mV was known to increase calcium influx through calcium-resting channels. According to this protocol, a significant increase of I GABA amplitude was observed. However, this effect was never obtained when the same protocol was applied on cell body pretreated with CdCl2. When the calmodulin blocker N-(6-aminohexyl)-5-chloro-1-naphtalene-sulfonamide or the calcium-calmodulin-dependent protein kinase blocker 1-[ N,O-bis(5-isoquinolinesulfonyl)- N-methyl-l-tyrosyl]-4-phenylpiperazine (KN-62) was added in the pipette solution, I GABA amplitude was decreased. Pressure ejection application of the cis-4-aminocrotonic acid (CACA) on DUM neuron cell body held at −50 mV, evoked a Cl− inward current which was insensitive to CdCl2. The Hill plot yielded a Hill coefficient of 2.3, and the I-V curve was always linear in the negative potential range with a slope conductance of 32.4 ± 1.1 nS. These results, similar to those obtained with GABA in the presence of CdCl2 and KN-62, indicated that CACA activated one subtype of GABA receptor. Our study demonstrated that at least two distinct subtypes of Cl−-dependent GABA receptors were expressed in DUM neurons, one of which is regulated by an intracellular Ca2+-dependent mechanism via a calcium-dependent protein kinase. The consequences of the modulatory action of Ca2+ in GABA receptors function and their sensitivity to insecticide are discussed.

scholarly journals Nervous System ofPeriplaneta americanaCockroach as a Model in Toxinological Studies: A Short Historical and Actual View

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Maria Stankiewicz ◽  
Marcin Dąbrowski ◽  
Maria Elena de Lima
Keyword(s):  
Nervous System ◽  
Periplaneta Americana ◽  
Giant Axon ◽  
Gap Technique ◽  
Fiber Oil ◽  
Wide Range ◽  
Pharmacological Studies ◽  
Dum Neurons ◽  
Dorsal Unpaired Median

Nervous system ofPeriplaneta americanacockroach is used in a wide range of pharmacological studies, including electrophysiological techniques. This paper presents its role as a preparation in the development of toxinological studies in the following electrophysiological methods: double-oil-gap technique on isolated giant axon, patch-clamp on DUM (dorsal unpaired median) neurons, microelectrode techniquein situconditions on axon in connective and DUM neurons in ganglion, and single-fiber oil-gap technique on last abdominal ganglion synapse. At the end the application of cockroach synaptosomal preparation is mentioned.

Dorsal Unpaired Median Neurons of Locusta migratoria Express Ivermectin- and Fipronil-Sensitive Glutamate-Gated Chloride Channels

2007 ◽  
Vol 97 (4) ◽  
pp. 2642-2650 ◽  
Author(s):  
Daniel Janssen ◽  
Christian Derst ◽  
Roeland Buckinx ◽  
Jimmy Van den Eynden ◽  
Jean-Michel Rigo ◽  
...  
Keyword(s):  
Chloride Channels ◽  
Locusta Migratoria ◽  
Functional Expression ◽  
Equilibrium Potential ◽  
Current Response ◽  
Metathoracic Ganglion ◽  
Continuous Application ◽  
Dum Neurons ◽  
Induced Changes ◽  
Dorsal Unpaired Median

Together with type A GABA and strychnine-sensitive glycine receptors, glutamate-gated chloride channels (GluCl) are members of the Cys-loop family of ionotropic receptors, which mediate fast inhibitory neurotransmission. To date, GluCls are found in invertebrates only and therefore represent potential specific targets for insecticides, such as ivermectin and fipronil. In this study, we identified the functional expression of GluCls in dorsal unpaired median (DUM) neurons of the metathoracic ganglion of Locusta migratoria using electrophysiological and molecular biological techniques. In whole cell patch-clamped DUM neurons, glutamate-induced changes in both their membrane potentials (current-clamp) and currents (voltage-clamp) were dependent on the chloride equilibrium potential. On continuous application of glutamate, the glutamate-elicited current response became rapidly and completely desensitized. Application of glutamate in the presence of 10 μM fipronil or 100 μM picrotoxin reversibly decreased GluCl-mediated currents by 87 and 39%, respectively. Furthermore, 1 μM ivermectin induced a persistent chloride current, suggesting the expression of ivermectin-sensitive GluCl α subunits. A degenerate PCR/RACE strategy was used to clone the full-length L. migratoria LmGlClα subunit. Finally, RT-PCR experiments demonstrated the presence of LmGluClα transcripts in locust DUM neurons. Our results provide the first direct evidence of a functional ivermectin-sensitive GluCl channel on the cell surface of DUM neurons of L. migratoria.

Sign in / Sign up

Export Citation Format

Share Document