Document Detail


Modulation of peptide release from single identified Aplysia neurons in culture.
MedLine Citation:
PMID:  1326609     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Aplysia neurons B1 and B2 contain large amounts of the neuropeptides SCPA and SCPB. When grown in culture, individual B1 and B2 cells incorporate 35S-methionine into the SCPs, which can be released in a stimulus- and calcium-dependent fashion (Lloyd et al., 1986). We now show that single cells can be stimulated in a manner to evoke release of the SCPs that declines only slightly with repeated stimulation. This has allowed us to examine the ability of several physiologically relevant agonists to modulate the stimulus-evoked release of the SCPs. Bath application of either FMRFamide or 5-HT resulted in a significant decrease in the amount of SCPs released by intracellular stimulation of B1 or B2. The action of 5-HT was dose dependent with an inhibition of release of approximately 70% at a concentration of 100 microM. SCPA did not significantly affect release. The bath application of several compounds that are expected to elevate intracellular levels of cAMP were also found to depress release. To investigate the possibility that the agonists inhibited the release of the SCPs via a hyperpolarization of membrane potential (and perhaps a loss of spikes in the neurites), we examined the actions of 5-HT, FMRFamide, and SCPA on several electrophysiological parameters intended to monitor the level of cell excitability. Surprisingly, even though 5-HT depressed the release of the SCPs from both cells, it depolarized and increased the excitability of B1, and hyperpolarized and decreased the excitability of B2. Furthermore, in contrast to the effects seen in culture, 5-HT depolarized both B1 and B2 in situ.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
M D Whim; P E Lloyd
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  12     ISSN:  0270-6474     ISO Abbreviation:  J. Neurosci.     Publication Date:  1992 Sep 
Date Detail:
Created Date:  1992-10-19     Completed Date:  1992-10-19     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  3545-53     Citation Subset:  IM    
Affiliation:
Department of Pharmacological and Physiological Sciences, University of Chicago, Illinois 60637.
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / drug effects
Animals
Aplysia / metabolism*,  physiology
Cells, Cultured
Cyclic AMP / metabolism
Electric Conductivity
Electric Stimulation
FMRFamide
Membrane Potentials / drug effects
Neurons / metabolism*,  physiology
Neuropeptides / antagonists & inhibitors,  metabolism*,  pharmacology
Serotonin / pharmacology
Grant Support
ID/Acronym/Agency:
NS23596/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/Neuropeptides; 50-67-9/Serotonin; 60-92-4/Cyclic AMP; 64190-70-1/FMRFamide; 84746-43-0/small cardioactive peptide B; 98035-79-1/small cardioactive peptide A

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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