Anatomy and targets of dorsal unpaired median neurones in the terminal abdominal ganglion of the male cockroachPeriplaneta americana L.

Sinakevitch, Irina; Geffard, M.; Pelhate, M.; Lapied, Bruno

doi:10.1002/(sici)1096-9861(19960325)367:1<147::aid-cne9>3.0.co;2-3

Cited by 29 publications

(2 citation statements)

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“…DUM neurons were isolated from the cockroach TAG (Lapied et al., 1993; Sinakevitch et al., 1996). After being carefully dissected, the TAG was placed in the standard saline extracellular solution.…”

Section: Methodsmentioning

confidence: 99%

The calcium–calmodulin‐dependent protein kinase kinase inhibitor, STO‐609, inhibits nicotine‐induced currents and intracellular calcium increase in insect neurosecretory cells

Taha,

Houchat,

Taillebois

et al. 2024

Journal of Neurochemistry

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Insect neuronal nicotinic acetylcholine receptors (nAChRs) are transmembrane receptors that play a key role in the development and synaptic plasticity of both vertebrates and invertebrates and are considered to be major targets of neonicotinoid insecticides. We used dorsal unpaired median (DUM) neurons, which are insect neurosecretory cells, in order to explore the intracellular mechanisms leading to the regulation of insect neuronal nAChRs in more detail. Using whole‐cell patch‐clamp and fura‐2AM calcium imaging techniques, we found that a novel CaMKK/AMPK pathway could be involved in the intracellular regulation of DUM neuron nAChRs. The CaMKK selective inhibitor, STO, reduced nicotinic current amplitudes, and strongly when co‐applied with α‐Bgt. Interestingly, intracellular application of the AMPK activator, A‐76, prevented the reduction in nicotine‐induced currents observed in the presence of the AMPK inhibitor, dorsomorphin. STO prevented the increase in intracellular calcium induced by nicotine, which was not dependent on α‐Bgt. Currents induced by 1 mM LMA, a selective activator of nAChR2, were reduced under bath application of STO, and mecamylamine, which blocked nAChR2 subtype, inhibited the increase in intracellular calcium induced by LMA. These findings provide insight into potential complex mechanisms linked to the modulation of the DUM neuron nAChRs and CaMKK pathway.

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Section: Methodsmentioning

confidence: 99%

The calcium–calmodulin‐dependent protein kinase kinase inhibitor, STO‐609, inhibits nicotine‐induced currents and intracellular calcium increase in insect neurosecretory cells

Taha,

Houchat,

Taillebois

et al. 2024

Journal of Neurochemistry

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“…Journal of Physiology (1998) In addition to the diversity of the classical depolarizationactivated Na+, K+ and ci+ currents, the ionic currents activated upon hyperpolarization also make a significant contribution to the modulation of neuronal pacemaker activity. In the terminal abdominal ganglion of the cockroach central nervous system, a distinctive population of octopaminergic neurosecretory cells (Sinakevitch et al 1996), called the dorsal unpaired median (DUM) neurones generate spontaneous repetitive action potentials with regular intervals. In the sequence of ionic events that are needed to maintain pacemaker activity (Grolleau & Lapied, 1996), the presence of hyperpolarization-activated inward currents in DUM neurones and their putative contribution in the generation of the pacemaker activity, have never been established.…”

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confidence: 99%

Comparative & Invertebrate Neuroscience

1998

The Journal of Physiology

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The fmewing stretch receptor (fSR) of the locust, Schistocerca gregaria, makes monosynaptic cholinergic connections with the first basalar motoneuron (BA1) that innervates a wing depressor muscle. At this synapse, 102Ppostsynaptic nicotinic cholinergic receptors are mainly responsible for producing excitatory postsynaptic potentials (EPSPs). Muscarinic cholinergic receptors, occurring presynaptically, are involved in downregulation of acetylcholine (ACh) release from the terminals of the fSR (Leitch & Pitman, 1995). Recent studies demonstrate that presynaptic muscarinic receptors also modulate ACh release from the fSR in another species of locust, Locusta migratoria. These studies have provided information about the mechanisms involved in the control of synaptic transmission.Application of general muscarinic antagonists (e.g. scopolamine and atropine) to an isolated nerve cord preparation causes an increase in EPSP amplitude evoked in BA1 by electrical stimulation of fSR. Scopolamine (10-6 M) caused a mean increase in EPSP amplitude of 9% (+S.E.M., 2·8 ; -S.E.M., 2·4; n = 8; arc-sine transformed data), whereas the same concentration of this antagonist depressed responses to ACh pressure-applied to the soma of BA1 (17·6 % decrease; +S.E.M., 1·9; -S.E.M., 1·8; n = 5; arc-sine transformed data). These observations indicate that enhancement of EPSP amplitude by scopolamine results from blockade of muscarinic receptors on neurons presynaptic to BA1. Presynaptic muscarinic receptors may be located on the fSR itself, and/or on inhibitory interneurons which once activated via the muscarinic receptors, inhibit ACh release from the presynaptic terminals of the fSR. Electron-microscopical immunocytochemistry has revealed that the fSR does receive presynaptic inputs from neurons that are immunoreactive to GABA.Application of the GABA antagonist picrotoxin (10-6 M) enhanced evoked EPSP amplitudes by 28% (+S.E.M., 5·4; -S.E.M., 5·1; n = 8; arc-sine transformed data). Although the picrotoxin-evoked enhancement of EPSP amplitude could be due to blockade of presynaptic GABA receptors, which would normally inhibit ACh release, it could also act by increasing the sensitivity of BA1 to ACh . To eliminate the latter possibility, we determined the effect of picrotoxin (10-6 M) on responses to ACh pressure-applied to the soma of BAl. These responses were not enhanced by picrotoxin (n = 5). Application of scopolamine (10-6 M) to a preparation incubated with picrotoxin (10-6 M) slightly decreased EPSP amplitudes, evoked in BA1 by electrical stimulation of fSR, by 15·9% (+S.E.M., 8·3; -S.E.M., 8·5; n = 5; arc-sine transformed data). This suggests that at least some muscarinic receptors are located on GABAergic interneurons that presynaptically inhibit transmitter release from fSR. This work was supported by a BBSRC studentship and University of Durham Equipment Grant awarded to B.L. REFERENCE Leitch, B. & Pitman, RM. (1995). J Neurobiol. 28,455-464. Physiology (1998) Modulation of synaptic transmission is crucial to most behavioural ad...

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Innervation of the heart of the adult fruit fly, Drosophila melanogaster

Dulcis

Levine

2003

J of Comparative Neurology

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The innervation of the adult abdominal heart of Drosophila melanogaster was studied by neuronal staining with green fluorescent protein and immunocytochemical techniques. The investigation was undertaken to determine whether the adult heart receives neuronal input or whether its complex activity must be considered independent from the nervous system. The larval heart lacks innervation, suggesting that the cardiac impulse is totally myogenic. At metamorphosis, segmental neural processes grow onto the myocardium. A pair of transverse nerves innervates bilaterally each cardiac chamber and its alary muscles. These nerve terminals are immunoreactive to glutamate and form unique synaptic structures on the ventral layer of longitudinal cardiac muscles of the conical chamber. This characteristic cardiac synapse may represent part of the neural mechanism controlling the retrograde heartbeat, and, thus, the cardiac reversal that is characteristic of adults. In addition, crustacean cardioactive peptide-immunoreactive fibers originating from peripheral, bipolar neurons (BpNs) fasciculate with the transverse nerve projections and terminate segmentally throughout the abdominal heart. An additional cluster composed of four large, CCAP-positive neurons innervates the terminal chamber. The cardioacceleratory effect of CCAP release at this location may modulate the properties of a pacemaker producing the anterograde heartbeat.

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Anatomy and targets of dorsal unpaired median neurones in the terminal abdominal ganglion of the male cockroachPeriplaneta americana L.

Cited by 29 publications

References 68 publications

The calcium–calmodulin‐dependent protein kinase kinase inhibitor, STO‐609, inhibits nicotine‐induced currents and intracellular calcium increase in insect neurosecretory cells

The calcium–calmodulin‐dependent protein kinase kinase inhibitor, STO‐609, inhibits nicotine‐induced currents and intracellular calcium increase in insect neurosecretory cells

Comparative & Invertebrate Neuroscience

Innervation of the heart of the adult fruit fly, Drosophila melanogaster

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