Octopamine-like immunoreactivity in the dorsal unpaired median (DUM) neurons innervating the accessory gland of the male cockroach Periplaneta americana

1994 ◽  
Vol 276 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Irina G. Sinakevitch ◽  
Michel Geffard ◽  
Marcel Pelhate ◽  
Bruno Lapied
Keyword(s):  
Periplaneta Americana ◽  
Accessory Gland ◽  
Dum Neurons ◽  
Dorsal Unpaired Median

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.

Ca2+ Currents in Central Insect Neurons: Electrophysiological and Pharmacological Properties

1997 ◽  
Vol 77 (1) ◽  
pp. 186-199 ◽  
Author(s):  
Dieter Wicher ◽  
Heinz Penzlin
Keyword(s):  
Periplaneta Americana ◽  
Low Voltage ◽  
Fast Time ◽  
Channel Blockers ◽  
Pharmacological Properties ◽  
Patch Clamp Technique ◽  
Whole Cell Patch Clamp ◽  
Blocking Effects ◽  
Dum Neurons ◽  
Maximal Peak

Wicher, Dieter, and Heinz Penzlin. Ca2+ currents in central insect neurons: electrophysiological and pharmacological properties. J. Neurophysiol. 77: 186–199, 1997. Ca2+ currents in dorsal unpaired median (DUM) neurons isolated from the fifth abdominal ganglion of the cockroach Periplaneta americana were investigated with the whole cell patch-clamp technique. On the basis of kinetic and pharmacological properties, two different Ca2+ currents were separated in these cells: mid/low-voltage-activated (M-LVA) currents and high-voltage-activated (HVA) currents. M-LVA currents had an activation threshold of −50 mV and reached maximal peak values at −10 mV. They were sensitive to depolarized holding potentials and decayed very rapidly. The decay was largely Ca2+ dependent. M-LVA currents were effectively blocked by Cd2+ median inhibiting concentration (IC50 = 9 μM), but they also had a remarkable sensitivity to Ni2+ (IC50 = 19 μM). M-LVA currents were insensitive to vertebrate LVA channel blockers like flunarizine and amiloride. The currents were, however, potently blocked by ω-conotoxin MVIIC (1 μM) and ω-agatoxin IVA (50 nM). The blocking effects of ω-toxins developed fast (time constant τ = 15 s) and were fully reversible after wash. HVA currents activated positive to −30 mV and showed maximal peak currents at +10 mV. They were resistant to depolarized holding potentials up to −50 mV and decayed in a less pronounced manner than M-LVA currents. HVA currents were potently blocked by Cd2+ (IC50 = 5 μM) but less affected by Ni2+ (IC50 = 40 μM). These currents were reduced by phenylalkylamines like verapamil (10 μM) and benzothiazepines like diltiazem (10 μM), but they were insensitive to dihydropyridines like nifedipine (10 μM) and BAY K 8644 (10 μM). Furthermore, HVA currents were sensitive to ω-conotoxin GVIA (1 μM). The toxin-induced reduction of currents appeared slowly (τ ∼ 120 s) and the recovery after wash was incomplete in most cases. The dihydropyridine insensitivity of the phenylalkylamine-sensitive HVA currents is a property the cockroach DUM cells share with other invertebrate neurons. Compared with Ca2+ currents in vertebrates, the DUM neuron currents differ considerably from the presently known types. Although there are some similarities concerning kinetics, the pharmacological profile of the cockroach Ca2+ currents especially is very different from profiles already described for vertebrate currents.

Imidacloprid actions on insect neuronal acetylcholine receptors

1997 ◽  
Vol 200 (21) ◽  
pp. 2685-2692 ◽  
Author(s):  
S Buckingham ◽  
B Lapied ◽  
H Corronc ◽  
F Sattelle
Keyword(s):  
Nervous System ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Periplaneta Americana ◽  
Muscarinic Acetylcholine Receptors ◽  
Nicotinic Acetylcholine ◽  
Neonicotinoid Insecticide ◽  
Dose Dependent ◽  
Dorsal Unpaired Median ◽  
Giant Interneurone

The neonicotinoid insecticide Imidacloprid acts at three pharmacologically distinct acetylcholine receptor (AChR) subtypes in the cockroach (Periplaneta americana) nervous system, but is ineffective on muscarinic receptors. Imidacloprid (3-100µmoll-1) induced dose-dependent depolarizations at cockroach cercal afferent/giant interneurone synapses. These responses were insensitive to 20µmoll-1 atropine but were completely blocked by the nicotinic antagonist mecamylamine (50µmoll-1). Similarly, Imidacloprid-induced depolarizations of cultured cockroach dorsal unpaired median (DUM) neurones dissociated from the same (terminal abdominal) ganglion were also completely blocked by 100µmoll-1 mecamylamine. However, two components of the response could be distinguished on the basis of their differential sensitivities to 0.1µmoll-1-bungarotoxin (-BTX), which selectively blocks AChRs with 'mixed' nicotinic/muscarinic pharmacology in this preparation. This indicates that Imidacloprid affects both AChRs sensitive to -BTX and -BTX-insensitive nicotinic acetylcholine receptors (nAChRs). Thus, in the cockroach, Imidacloprid activates -BTX-sensitive synaptic nAChRs in giant interneurones, -BTX-insensitive extrasynaptic nAChRs in DUM neurones, and a recently characterized DUM neurone 'mixed' AChR that is sensitive to both nicotinic and muscarinic ligands. Imidacloprid does not act on muscarinic acetylcholine receptors (mAChRs) present on DUM neurone cell bodies and at the cercal afferent/giant interneurone synapses. This study shows that Imidacloprid can act on pharmacologically diverse nAChR subtypes.

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.

THE EFFECT OF JUVENILE HORMONE ON THE FUNCTION OF THE ACCESSORY GLAND OF THE ADULT MALE COCKROACH PERIPLANETA AMERICANA (ORTHOPTERA: BLATTIDAE)

1973 ◽  
Vol 105 (10) ◽  
pp. 1275-1280 ◽  
Author(s):  
W. D. Blaine ◽  
S. E. Dixon
Keyword(s):  
Juvenile Hormone ◽  
Adult Male ◽  
Protein Production ◽  
Periplaneta Americana ◽  
Accessory Gland ◽  
Corpora Allata ◽  
Adult Males ◽  
Normal Amount ◽  
Accessory Glands

AbstractThe juvenile hormone was necessary for the sex accessory glands in newly metamorphosed, adult males, to produce a normal amount of spermatophore material. Protein production could be restored to normal in allatectomized newly metamorphosed roaches by implanting adult or nymphal roach corpora allata. In decapitated roaches, the weight of the accessory gland is reduced drastically. The weight of the gland could be increased by implanting adult roach corpora allata, or by injecting juvenile hormone.

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