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Involvement of ryanodine receptors in EPYLRFamide-mediated reduction of acetylcholine-induced inward currents in Helix lucorum identified neurones

Involvement of ryanodine receptors in EPYLRFamide-mediated reduction of acetylcholine-induced inward currents in Helix lucorum identified neurones
Involvement of ryanodine receptors in EPYLRFamide-mediated reduction of acetylcholine-induced inward currents in Helix lucorum identified neurones
The effects of several modulators of ryanodine receptors (RYRs) on the reduction of acetylcholine induced inward current (ACh-current) evoked by EPYLRFamide (5 ?M, bath application), the potent N-terminally modified analogue of the endogenous Helix heptapeptide SEPYLRFamide, were investigated. These modulators were applied intracellularly. Inward currents were recorded from identified Helix lucorum LPa2, LPa3, RPa3, RPa2 neurones in ganglia preparations using the two-electrode voltage clamp technique. ACh was applied ionophoretically. BAPTA (0.1 mM), chelator of intracellular Ca2+ ryanodine (0.1 mM), agonist/antagonist of RYRs and dantrolene (0.1 mM), antagonist of RYRs decrease the effect of EPYLRFamide. Adenosine (1 mM), ?,?-methylene ATP (0.1 mM), the nonhydrolisable ATP analogue and cyclic adenosine diphosphate ribose (0.1 mM) (agonists of RYRs) potentiate the modulatory effect of EPYLRFamide. Ruthenium red ( mM), antagonist of RYRs and caffeine ( mM), agonist of RYRs do not change the modulatory effect of EPYLRFamide. These data suggest that intracellular Ca2+ and RYRs are involved in the modulatory effect of EPYLRFamide on ACh-currents. It was concluded that EPYLRFamide decreases ACh-current through elevation of basal intracellular level of a putative endogenous agonist of RYRs which activates RYR-dependent mobilization of Ca2+ by binding to the adenine nucleotide site of the ryanodine receptor-channel complex and does not bind the site activated by caffeine.
inward current, fmrf amide, analog, N terminal-sequence, cholinergic receptor, helix lucorum, biological receptor, helicidae, pulmonata, gastropoda, mollusca, invertebrata
0167-0115
83-93
Pivovarov, A.S.
9a8cb25d-9369-413c-a424-4788edf97da6
Chad, J.E.
d220e55e-3c13-4d1d-ae9a-1cfae8ccfbe1
Walker, R.J.
b6597591-587e-488a-8a54-89156c42ce8d
Pivovarov, A.S.
9a8cb25d-9369-413c-a424-4788edf97da6
Chad, J.E.
d220e55e-3c13-4d1d-ae9a-1cfae8ccfbe1
Walker, R.J.
b6597591-587e-488a-8a54-89156c42ce8d

Pivovarov, A.S., Chad, J.E. and Walker, R.J. (2000) Involvement of ryanodine receptors in EPYLRFamide-mediated reduction of acetylcholine-induced inward currents in Helix lucorum identified neurones. Regulatory Peptides, 88 (1-3), 83-93. (doi:10.1016/S0167-0115(99)00125-1).

Record type: Article

Abstract

The effects of several modulators of ryanodine receptors (RYRs) on the reduction of acetylcholine induced inward current (ACh-current) evoked by EPYLRFamide (5 ?M, bath application), the potent N-terminally modified analogue of the endogenous Helix heptapeptide SEPYLRFamide, were investigated. These modulators were applied intracellularly. Inward currents were recorded from identified Helix lucorum LPa2, LPa3, RPa3, RPa2 neurones in ganglia preparations using the two-electrode voltage clamp technique. ACh was applied ionophoretically. BAPTA (0.1 mM), chelator of intracellular Ca2+ ryanodine (0.1 mM), agonist/antagonist of RYRs and dantrolene (0.1 mM), antagonist of RYRs decrease the effect of EPYLRFamide. Adenosine (1 mM), ?,?-methylene ATP (0.1 mM), the nonhydrolisable ATP analogue and cyclic adenosine diphosphate ribose (0.1 mM) (agonists of RYRs) potentiate the modulatory effect of EPYLRFamide. Ruthenium red ( mM), antagonist of RYRs and caffeine ( mM), agonist of RYRs do not change the modulatory effect of EPYLRFamide. These data suggest that intracellular Ca2+ and RYRs are involved in the modulatory effect of EPYLRFamide on ACh-currents. It was concluded that EPYLRFamide decreases ACh-current through elevation of basal intracellular level of a putative endogenous agonist of RYRs which activates RYR-dependent mobilization of Ca2+ by binding to the adenine nucleotide site of the ryanodine receptor-channel complex and does not bind the site activated by caffeine.

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More information

Published date: 17 March 2000
Keywords: inward current, fmrf amide, analog, N terminal-sequence, cholinergic receptor, helix lucorum, biological receptor, helicidae, pulmonata, gastropoda, mollusca, invertebrata

Identifiers

Local EPrints ID: 56629
URI: https://eprints.soton.ac.uk/id/eprint/56629
ISSN: 0167-0115
PURE UUID: 1671e261-6cfd-43b8-bff2-57717a53ba3b
ORCID for J.E. Chad: ORCID iD orcid.org/0000-0001-6442-4281

Catalogue record

Date deposited: 11 Aug 2008
Last modified: 14 Mar 2019 01:56

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