Primary Structure of a New Neuropeptide, Cerebral Peptide 2, Purified from Cerebral Ganglia of <i>Aplysia</i>

Phares, Gregg A.; Walent, Jane H.; Niece, Ronald L.; Kumar, Santosh; Ericsson, Lowell H.; Kowalak, Jeffrey A.; Lloyd, Philip E.

doi:10.1021/bi953081y

Cited by 15 publications

(15 citation statements)

References 30 publications

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“…The first is cerebral peptide 2 (CP2), a 41-residue amidated peptide that is colocalized with CP1 but is present in lower amounts (Phares and Lloyd, 1996b;Phares et al, 1996); it is not contained in the APGWamide preprohormone (this study). The second is an unidentified peptide (Phares and Lloyd, 1996a) that was seen only in H cluster neurons, but not in every neuron that contained CP1 (G. Phares, personal communication).…”

Section: Discussionmentioning

confidence: 90%

Molecular cloning of a cDNA encoding the neuropeptides APGWamide and cerebral peptide 1: Localization of APGWamide-like immunoreactivity in the central nervous system and male reproductive organs ofAplysia

Fan

Croll

et al. 1997

J. Comp. Neurol.

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While much is known about the neural and endocrine mechanisms that control egg laying in the gastropod mollusk Aplysia, relatively little is known about the regulation of male reproductive activity in this simultaneous hermaphrodite. In the present study, we have cloned and sequenced a cDNA that encodes a precursor protein, the predicted posttranslational processing of which presumably generates nine copies of the neuropeptide Ala-Pro-Gly-Trp-NH2 (APGWamide), five connecting peptide sequences, and a C-terminal peptide. The sequence of one connecting peptide is identical to the previously characterized cerebral peptide 1. Northern blot analysis identified two major APGWamide mRNA transcripts (approximately 1.3 kb, approximately 2.4 kb), which were present in central nervous system ganglia, but were most abundant in the right cerebral and right pedal ganglia. Immunohistochemical studies using sexually mature Aplysia demonstrated that the vast majority of APGWamide-like immunoreactivity was localized in 30-40 neurons along the anterior and medial margins of the right cerebral ganglion and in a cluster of 15-20 neurons in the right pedal ganglion. A total of only about ten immunoreactive neurons were located in other ganglia. Immunohistochemistry also demonstrated that APGWamide was present in the reproductive organs that participate in the storage or transport of sperm, including the small hermaphroditic duct (site of sperm storage before mating), the white hemiduct (also known as the copulatory duct), and penial complex. As a group, these data suggest that APGWamide may play a role in regulating male reproductive function in Aplysia, as it does in other gastropods.

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Section: Discussionmentioning

confidence: 90%

Molecular cloning of a cDNA encoding the neuropeptides APGWamide and cerebral peptide 1: Localization of APGWamide-like immunoreactivity in the central nervous system and male reproductive organs ofAplysia

Fan

Croll

et al. 1997

J. Comp. Neurol.

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“…CBI-2 triggers motor programs using fast cholinergic transmission (Hurwitz et al, 2003). In addition to ACh, two neuropeptides, FCAP and CP2 (Phares et al, 1996; Sweedler et al, 2002) are present in CBI-2 (Morgan et al, 2000; Koh et al, 2003). Given that stimulation paradigms that produce repetition priming have been shown to be favorable for peptide release in Aplysia (Whim and Lloyd, 1989; Cropper et al, 1990; Whim and Lloyd, 1990; Vilim et al, 1996b; Brezina et al, 2000b; Vilim et al, 2000), we reasoned that these peptides may be involved in repetition priming, i.e., an enhancement of motoneuronal firing when motor programs are elicited by repetitive CBI-2 stimulation.…”

Section: Resultsmentioning

confidence: 99%

“…Feeding circuit activating peptide (FCAP) (SynPep, Dublin, CA) (Sweedler et al, 2002) and CP2 cerebral peptide 2 (CP2) (SynPep, Dublin, CA) (Phares et al, 1996; Vilim et al, 2001) were perfused at 10 −6 M, a concentration that produces maximum effects (Koh et al, 2003). In all experiments peptides were perfused at a rate of 0.3 ml/min.…”

Section: Methodsmentioning

confidence: 99%

Repetition Priming of Motoneuronal Activity in a Small Motor Network: Intercellular and Intracellular Signaling

Friedman

Weiss²

2010

Journal of Neuroscience

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The characteristics of central pattern generator (CPG) outputs are subject to extensive modulation. Previous studies of neuromodulation largely focused on immediate actions of neuromodulators, i.e., actions that were exerted at the time when either neuromodulators were present or neuromodulatory inputs to the CPG were active. However, neuromodulatory actions are known to persist when neuromodulators are no longer present. In Aplysia, stimulation of cerebral-buccal interneuron-2 (CBI-2), which activates the feeding CPG, produces a repetition priming of motor programs. This priming is reflected in an increase of firing of motoneurons. As CBI-2 contains two neuromodulatory peptides, FCAP (feeding circuit-activating peptide) and CP2 (cerebral peptide 2), we hypothesized that repetition priming may involve persistent peptidergic neuromodulation. We find that these peptides produce priming-like effects, i.e., they increase the firing of radula-opening (B48) and radula-closing (B8) motoneurons during motor programs. Proekt et al. (2004, 2007) showed that repetition priming of neuron B8 is implemented by modulatory inputs that B8 receives from the CPG. In contrast, our current findings indicate that priming of B48 may be implemented by a direct peptidergic modulation of its intrinsic characteristics via a pathway that activates cAMP. We suggest that the direct versus indirect, i.e., CPG-dependent, repetition priming may be related to the type of input that individual motoneurons receive from the CPG. We suggest that in motoneurons that are driven by concurrent excitation-inhibition, repetition priming is indirect as it is preferentially implemented via modulation of the output of CPGs. In contrast, in motoneurons that are driven by alternating excitation-inhibition, direct modulation of motoneurons may be preferentially used.

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“…Either artificial sea water (in m m : 460 NaCl, 10 KCl, 55 MgCl 2 , 11 CaCl 2 , and 10 HEPES buffer, pH7.6) or a 2 Mg 2+ /1.25 Ca 2+ high divalent solution (HiDi; in m m : 368 NaCl, 10 KCl, 101 MgCl 2 , 13.8 CaCl 2 , and 10 HEPES, pH 7.6; Friedman and Weiss, 2010) was superfused onto the preparation at 0.3 ml/min. Feeding Circuit Activating Peptide (FCAP; provided by Dr. J. Sweedler, University of Illinois, Urbana, IL; Sweedler et al, 2002) and Cerebral Peptide 2 (CP2; SynPep; Phares et al, 1996; Vilim et al, 2001) were applied at 1μ m concentrations in HiDi and were prepared daily from frozen aliquots. Intracellular recordings were performed with borosilicate electrodes filled with 0.6 m K 2 SO 4 and 60 m m KCl electrolyte solution.…”

Section: Methodsmentioning

confidence: 99%

Latent Modulation: A Basis for Non-Disruptive Promotion of Two Incompatible Behaviors by a Single Network State

Dacks

Weiss

2013

J. Neurosci.

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Behavioral states often preferentially enhance specific classes of behavior and suppress incompatible behaviors. In the nervous system, this may involve upregulation of the efficacy of neural modules that mediate responses to one stimulus and suppression of modules that generate antagonistic or incompatible responses to another stimulus. In Aplysia, prestimulation of egestive inputs [esophageal nerve (EN)] facilitates subsequent EN-elicited egestive responses and weakens ingestive responses to ingestive inputs [Cerebral-Buccal Interneuron (CBI-2)]. However, a single state can also promote incompatible behaviors in response to different stimuli. This is the case in Aplysia, where prestimulation of CBI-2 inputs not only enhances subsequent CBI-2-elicited ingestive responses, but also strengthens EN-elicited egestive responses. We used the modularly organized feeding network of Aplysia to characterize the organizational principles that allow a single network state to promote two opposing behaviors, ingestion and egestion, without the two interfering with each other. We found that the CBI-2 prestimulation-induced state upregulates the excitability of neuron B65 which, as a member of the egestive module, increases the strength of egestive responses. Furthermore,we found that this upregulation is likely mediated by the actions of the neuropeptides FCAP (Feeding Circuit Activating Peptide) and CP2 (Cerebral Peptide 2). This increased excitability is mediated by a form of modulation that we refer to as “latent modulation” because it is established during stimulation of CBI-2, which does not activate B65. However, when B65 is recruited into EN-elicited egestive responses, the effects of the latent modulation are expressed as a higher B65 firing rate and a resultant strengthening of the egestive response.

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Primary Structure of a New Neuropeptide, Cerebral Peptide 2, Purified from Cerebral Ganglia of Aplysia

Cited by 15 publications

References 30 publications

Molecular cloning of a cDNA encoding the neuropeptides APGWamide and cerebral peptide 1: Localization of APGWamide-like immunoreactivity in the central nervous system and male reproductive organs ofAplysia

Molecular cloning of a cDNA encoding the neuropeptides APGWamide and cerebral peptide 1: Localization of APGWamide-like immunoreactivity in the central nervous system and male reproductive organs ofAplysia

Repetition Priming of Motoneuronal Activity in a Small Motor Network: Intercellular and Intracellular Signaling

Latent Modulation: A Basis for Non-Disruptive Promotion of Two Incompatible Behaviors by a Single Network State

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