Neuropeptide diversity in <i>Ascaris</i>: An immunocytochemical study

Sithigorngul, Paisarn; Stretton, A. O. W.; Cowden, Cynthia

doi:10.1002/cne.902940306

Cited by 77 publications

(70 citation statements)

References 30 publications

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“…However, the use of such antibodies in immunocytochemical studies does give important information: (a) it identifies the functional class of neurons that contain the epitope (e.g. MNs, premotor interneurons, sensory neurons), and gives some preliminary functional information as well as guiding the choice of which class of peptide may be most interesting to isolate chemically; (b) the recognition of distinct cellular staining patterns gives a minimum estimate of the number of different peptides present in the nervous system, since each immunologically distinct subset of neurons implies the existence of at least one distinct epitope -this led to the original estimate that there were at least 12 different peptide-like immunoreactivities in Ascaris (Sithigorngul, Stretton & Cowden, 1990). This number is now roughly doubled (Sithigorngul et al 1989;Davenport, Lee & Isaac, 1988;Brownlee, Fairweather & Johnston, 1993 a;Brownlee et al 1993Brownlee et al 6, 1994.…”

Section: Neuropeptidesmentioning

confidence: 99%

The motornervous system ofAscaris: electrophysiology and anatomy of the neurons and their control by neuromodulators

Davis

Stretton

1996

Parasitology

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Analysis of the electrical properties of neurons in the motornervous system of Ascaris sutom suggests that it is largely an analogue system. The motorneurons do not conduct action potentials and they release transmitter tonically at their normal resting potential; transmitter release is increased or decreased as a continuous function of membrane potential. Despite extensive physiological descriptions of the electrical properties of the neurons and their synapses, as well as morphological descriptions of the synaptic circuitry of the system, the predicted activities of the neurons in the circuit differ from those observed by direct recording in semi-intact behaving animals. We conclude that the description of the circuit is incomplete. There are several possibilities for the missing elements, including chemical, proprioceptive, and additional neuronal components. Recently, attention has been focussed most heavily on the intercellular chemical signalling systems; in addition to those mediated by classical neurotransmitters, a surprisingly complex array of neuropeptides has been identified. One family of these peptides, the AF peptides, has been analyzed in detail. It comprises at least 20 peptides, and they fall into sequence-related subfamilies. One of these subfamilies, containing 6 peptides, is encoded by a single transcript, suggesting that the AF peptides are under multiple genetic control. All AF peptides tested have potent activity on the motornervous system and/or on muscle. There are multiple physiological activities, and cellular localization studies show multiple patterns of cellular expression. Studies on Panagrellus and Caenorhabditis emphasize the diversity of this family and its genetic control.

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Section: Neuropeptidesmentioning

confidence: 99%

The motornervous system ofAscaris: electrophysiology and anatomy of the neurons and their control by neuromodulators

Davis

Stretton

1996

Parasitology

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“…Neuropeptides have been particularly well studied in nematodes, where the discovery of new peptides has been approached by two general methods, chemical analysis of the peptides themselves [2–11], and database mining of genomic or EST libraries [12–15]. Localization studies in nematodes show that the majority of these neuropeptides are expressed in neurons [11, 16–20]. Neurons in nematodes are few in number and are simple geometrically.…”

Section: Introductionmentioning

confidence: 99%

Changes in cyclic nucleotides, locomotory behavior, and body length produced by novel endogenous neuropeptides in the parasitic nematode Ascaris suum

Reinitz¹,

Pleva²,

Stretton³

2011

Molecular and Biochemical Parasitology

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Recent technical advances have rapidly advanced the discovery of novel peptides, as well as the transcripts that encode them, in the parasitic nematode Ascaris suum. Here we report that many of these novel peptides produce profound and varied effects on locomotory behavior and levels of cyclic nucleotides in A. suum. We investigated the effects of 31 endogenous neuropeptides encoded by transcripts afp-1, afp-2, afp-4, afp-6, afp-7, and afp-9 - 14, (afp: Ascaris FMRFamide –like Precursor protein) on cyclic nucleotide levels, body length and locomotory behavior. Worms were induced to generate anteriorly propagating waveforms, peptides were injected into the pseudocoelomic cavity, and changes in the specific activity (nmol/mg protein) of second messengers cAMP (3′5′ cyclic adenosine monophosphate) and cGMP (3′5′ cyclic guanosine monophosphate) were determined. Many of these neuropeptides changed the levels of cAMP (both increases and decreases were found), whereas few neuropeptides changed the level of cGMP. A subset of the peptides that lowered cAMP was investigated for effects on the locomotory waveform and on body length. Injection of AF19, or AF34 (afp-13), AF9 (afp-14), AF26 or AF41 (afp-11) caused immediate paralysis and cessation of propagating body waveforms. These neuropeptides also significantly increased body length. In contrast, injection of AF15 (afp-9) reduced the body length, and decreased the amplitude of waves in the body waveform. AF30 (afp-10) produced worms with tight ventral coils. Although injection of neuropeptides encoded by afp-1 (AF3, AF4, AF10 or AF13) produced an increased number of exaggerated body waves, there were no effects on either cAMP or cGMP. By injecting peptides into behaving A. suum, we have provided an initial screen of the effects of novel peptides on several behavioral and biochemical parameters.

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“…In the central nervous system (CNS) of invertebrates, NPY-like immunoreactivity has been described in ascidians (Pestarino 1992), gastropods (Yui et al 1985;Honma et al 1994), insects (Rémy et al 1988;Schoofs et al 1988), polychaetes (Díaz-Miranda et al 1991), nematodes (Sithigorngul et al 1990;Brownlee et al 1993), and flatworms (Skuce et al 1990;Marks et al 1993). In the insect CNS, the colocalization of NPY-like and FMRFamide-like immunoreactivities has been demonstrated in the cephalic and thoracic nervous systems by using adjacent sections (Rémy et al 1988).…”

Section: Introductionmentioning

confidence: 99%

Neuropeptide Y-immunoreactive neuronal system and colocalization with FMRFamide in the optic lobe and peduncle complex of the octopus (Octopus vulgaris)

et al. 2001

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The distribution of neuropeptide Y (NPY)-like immunoreactivity and its colocalization with FMRFamide were investigated in the optic lobe and peduncle complex of the octopus ( Octopus vulgaris) by using immunohistochemical techniques. In the optic lobe cortex, NPY-immunoreactive (NPY-IR) fibers were observed in the plexiform layer, although no NPY-IR somata were observed in the outer or inner granular cell layers. In the optic lobe medulla, NPY-IR somata were seen in the cell islands, and abundant NPY-IR varicose fibers were observed in the neuropil. Most of the NPY-IR structures in the medulla showed FMRFamide-like immunoreactivity. In the peduncle lobe, abundant NPY-IR and FMRFamide-IR (NPY/FMRF-IR) varicose fibers were seen in the basal zone neuropil of the peduncle lobe. In the olfactory lobe, NPY/FMRF-IR varicose fibers were also abundant in the neuropil of the three lobules. NPY/FMRF-IR somata, with processes running to various neuropils, were scattered in the median and posterior lobules. In the optic gland, many NPY/FMRF-IR varicose fibers formed a honeycomb pattern. These observations suggest that NPY/FMRF-IR neurons in the optic lobes participate in the modulation of visual information and that those in the optic gland are involved in the regulation of endocrine function.

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Neuropeptide diversity in Ascaris: An immunocytochemical study

Cited by 77 publications

References 30 publications

The motornervous system ofAscaris: electrophysiology and anatomy of the neurons and their control by neuromodulators

The motornervous system ofAscaris: electrophysiology and anatomy of the neurons and their control by neuromodulators

Changes in cyclic nucleotides, locomotory behavior, and body length produced by novel endogenous neuropeptides in the parasitic nematode Ascaris suum

Neuropeptide Y-immunoreactive neuronal system and colocalization with FMRFamide in the optic lobe and peduncle complex of the octopus (Octopus vulgaris)

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