EPYLRFamide-mediated reduction of acetylcholine-induced inward currents in Helix lucorum-identified neurones: role of NAADP-dependent and IP3-dependent Ca2+ release from internal stores, calmodulin and Ca2+/calmodulin-dependent protein kinase II

Pivovarov, A. S.; Walker, Robert

doi:10.1016/s0167-0115(02)00221-5

Cited by 2 publications

(4 citation statements)

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“…These mechanisms have the same final target, the elevation of free intracellular Ca 2+ , and are closely related. (1) SEPYLRFamide → activation of membrane receptor → activation of G-protein → elevation of inositol-1,4,5-trisphosphate (IP 3 , second messenger) level → activation of IP 3 receptors → Ca 2+ release from internal store → elevation of intracellular free Ca 2+ [42]. (2) SEPYLRFamide → activation of membrane receptor → activation of G-protein → elevation of cyclic adenosine diphosphate-ribose (cADPR, second messenger) level → activation of ryanodine receptors → Ca 2+ release from internal store → elevation of intracellular free Ca 2+ [36].…”

Section: Discussionmentioning

confidence: 99%

“…Endogenous molluscan FMRFamide-related peptides (FaRPs): FMRFamide, SKPYMRFamide, SEPYLRFamide and its N-terminally modified analogues, EPYLRFamide, SEGYLRFamide, SRPYLRFamide, SKPYLRFamide and acetyl-SKPYMRFamide act as inhibitory neuromodulators of cholinergic transmission in H. aspersa [1,38,41] and Helix lucorum [36,39,40,42] parietal ganglia.…”

Section: Introductionmentioning

confidence: 99%

“…Our electrophysiological data show that intracellular free Ca 2+ is involved in the intracellular mechanism for the reduction of cholinosensitivity in Helix neurons by FaRPs [36,38,41]. Ryanodine receptors and IP 3 receptors may be involved in the inhibitory metabotropic effects of FaRPs on somatic cholinergic receptors of identified Helix neurons [36,38,41,42].…”

Section: Introductionmentioning

confidence: 99%

“…Ouabain reduces reversibly ACh-induced inward currents in identified H. lucorum neurons (LPa2, LPa3, RPa3, RPa2) [33,35,37] that were used in our investigations with FaRPs [36,38,39,40,42]. This ouabain-mediated metabotropic effect is Ca 2+ -dependent.…”

Section: Introductionmentioning

confidence: 99%

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Involvement of Na,K-pump in SEPYLRFamide-mediated reduction of cholinosensitivity in Helix neurons

Pivovarov

Foreman

Walker

2007

Regulatory Peptides

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SEPYLRFamide acts as an inhibitory modulator of acetylcholine (ACh) receptors in Helix lucorum neurones. Ouabain, a specific inhibitor of Na,K-pump, (0.1 mM, bath application) decreased the ACh-induced inward current (ACh-current) and increased the leak current. Ouabain decreased the modulatory SEPYLRFamide effect on the ACh-current. There was a correlation between the effects of ouabain on the amplitude of the ACh-current and on the modulatory peptide effect. Ouabain and SEPYLRFamide inhibited the activity of Helix aspersa brain Na,K-ATPase. Activation of Na,K-pump by intracellular injection of 3 M Na acetate or 3 M NaCl reduced the modulatory peptide effect on the ACh-current. An inhibitor of Na/Ca-exchange, benzamil (25 muM, bath application), and an inhibitor of Ca(2+)-pump in the endoplasmic reticulum, thapsigargin (TG, applied intracellularly), both prevented the effect of ouabain on SEPYLRFamide-mediated modulatory effect. Another inhibitor of Ca(2+)-pump in the endoplasmic reticulum, cyclopiazonic acid (applied intracellularly), did not prevent the effect of ouabain on SEPYLRFamide-mediated modulatory effect. These results indicate that Na,K-pump is responsible for the SEPYLRFamide-mediated inhibition of ACh receptors in Helix neurons. Na/Ca-exchange and intracellular Ca(2+) released from internal pools containing TG-sensitive Ca(2+)-pump are involved in the Na,K-pump pathway for the SEPYLRFamide-mediated inhibition of ACh receptors.

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Section: Discussionmentioning

confidence: 99%