The actions of neuroactive peptides on identified central neurons of helix aspersa
The actions of neuroactive peptides on identified central neurons of helix aspersa
Identified neurons from the suboesophageal ganglia of Helix aspersa were used to investigate the effects of invertebrate neuroactive peptides using intracellular recording techniques. Each peptide family was active on only a few neurons.
The Mytilus inhibitory peptide family, including GSPYFVamide isolated from H. aspersa, inhibited neurons through an increased conductance to K+ and Cl-, as demonstrated by ion manipulation and the use of channel modifiers. For maximum potency all 6 amino acid residues were required, the C terminal sequence PxFVamide was crucial for activity. Evidence suggested this H response was partly through a nitric oxide (NO) activation of guanylyl cyclase since responses were enhanced in the presence of cGMP and the NO donors SNP, SNAP and SNOG and reduced in the presence of the NOS inhibitor L-NAME, and guanylyl cyclase inhibitor, ODQ.
The S-Iamides, most with the structure xSSFVRIamide, were inhibitory on a very limited number of neurons, particularly E12 and E14a. This effect was through an increase in K+ conductance, probably an IA channel as indicated by the effects of TEA, 4-AP, CoCl2 and caesium in the saline. For maximum effect it was necessary to have a complete heptapeptide, the actual N terminal residue was less significant. Evidence indicated that cGMP and NO are probably not involved in the S-Iamide response, experiments using cAMP pathway analogues were inconclusive.
ACEP-1, isolated from Achatina, either excited or had a biphasic effect on cells. It reduced some ACh excitatory responses. The CCAP-related peptides mostly excited cells. SALMF-1 was weakly excitatory and CARP was only inhibitory on neurons.
It is proposed that neuroactive peptides are likely to play diverse roles in the physiology of the central nervous system of H. aspersa.
University of Southampton
Pedder, Sibella Margaretha
1999
Pedder, Sibella Margaretha
Pedder, Sibella Margaretha
(1999)
The actions of neuroactive peptides on identified central neurons of helix aspersa.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Identified neurons from the suboesophageal ganglia of Helix aspersa were used to investigate the effects of invertebrate neuroactive peptides using intracellular recording techniques. Each peptide family was active on only a few neurons.
The Mytilus inhibitory peptide family, including GSPYFVamide isolated from H. aspersa, inhibited neurons through an increased conductance to K+ and Cl-, as demonstrated by ion manipulation and the use of channel modifiers. For maximum potency all 6 amino acid residues were required, the C terminal sequence PxFVamide was crucial for activity. Evidence suggested this H response was partly through a nitric oxide (NO) activation of guanylyl cyclase since responses were enhanced in the presence of cGMP and the NO donors SNP, SNAP and SNOG and reduced in the presence of the NOS inhibitor L-NAME, and guanylyl cyclase inhibitor, ODQ.
The S-Iamides, most with the structure xSSFVRIamide, were inhibitory on a very limited number of neurons, particularly E12 and E14a. This effect was through an increase in K+ conductance, probably an IA channel as indicated by the effects of TEA, 4-AP, CoCl2 and caesium in the saline. For maximum effect it was necessary to have a complete heptapeptide, the actual N terminal residue was less significant. Evidence indicated that cGMP and NO are probably not involved in the S-Iamide response, experiments using cAMP pathway analogues were inconclusive.
ACEP-1, isolated from Achatina, either excited or had a biphasic effect on cells. It reduced some ACh excitatory responses. The CCAP-related peptides mostly excited cells. SALMF-1 was weakly excitatory and CARP was only inhibitory on neurons.
It is proposed that neuroactive peptides are likely to play diverse roles in the physiology of the central nervous system of H. aspersa.
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Published date: 1999
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Local EPrints ID: 464019
URI: http://eprints.soton.ac.uk/id/eprint/464019
PURE UUID: 85597139-86bc-4795-9ef2-fa6f295c3f6d
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Date deposited: 04 Jul 2022 21:00
Last modified: 04 Jul 2022 21:00
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Author:
Sibella Margaretha Pedder
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