In:
FEBS Letters, Wiley, Vol. 293, No. 1-2 ( 1991-11), p. 137-141
Abstract:
The C‐peptide of Locusta insulin‐related peptide, which is a 50 residue peptide originally isolated from the corpora cardiaca of the insect Locusta migratoria and to which we refer as 5‐kDa peptide, has been synthesised chemically by the solid‐phase metho, using a BOC strategy. Since this peptide contains in its sequence a potential monobasic cleavage site, we also synthesised its 1–38 residue‐related fragment, named 4‐kDa peptide, although we have no hints of its natural occurrence in the corpora cardiaca. Electrophysiological studies have shown that both the 5‐kDa and 4‐kDa peptides depolarise the membrane and increase the membrane conductance of neurones freshly isolated from the thoracic ganglia of Locusta . Under voltage‐clamp conditions, the current underlying these effects was inwardly directed and could be resolved into 2 components. One component, I(5‐kDa) 1 , activated at potentials more hyperpolarised than −50 mV, peaked at about −75 mV and was blocked by the potassium channel blockers cesium and rubidium. The second component, I(5‐kDa) 2 was activated at potentials more depolarised than −50 mV, increased with depolarisation and was not blocked by cesium and rubidium. The effects of the 5‐kDa and 4‐kDa peptides on the membrane potential and membrane conductance of Locusta neurones suggest that these peptides may have a physiological role in the central nervous system of insects.
Type of Medium:
Online Resource
ISSN:
0014-5793
,
1873-3468
DOI:
10.1016/0014-5793(91)81170-D
Language:
English
Publisher:
Wiley
Publication Date:
1991
detail.hit.zdb_id:
1460391-3
SSG:
12
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