CaV2.3 calcium channels control second-phase insulin release.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Concerted activation of different voltage-gated Ca2+ channel isoforms may determine the kinetics of insulin release from pancreatic islets. Here we have elucidated the role of R-type CaV2.3 channels in that process. A 20% reduction in glucose-evoked insulin secretion was observed in CaV2.3-knockout (CaV2.3–/–) islets, close to the 17% inhibition by the R-type blocker SNX482 but much less than the 77% inhibition produced by the L-type Ca2+ channel antagonist isradipine. Dynamic insulin-release measurements revealed that genetic or pharmacological CaV2.3 ablation strongly suppressed second-phase secretion, whereas first-phase secretion was unaffected, a result also observed in vivo. Suppression of the second phase coincided with an 18% reduction in oscillatory Ca2+ signaling and a 25% reduction in granule recruitment after completion of the initial exocytotic burst in single CaV2.3–/– ß cells. CaV2.3 ablation also impaired glucose-mediated suppression of glucagon secretion in isolated islets (27% versus 58% in WT), an effect associated with coexpression of insulin and glucagon in a fraction of the islet cells in the CaV2.3–/– mouse. We propose a specific role for CaV2.3 Ca2+ channels in second-phase insulin release, that of mediating the Ca2+ entry needed for replenishment of the releasable pool of granules as well as islet cell differentiation.

Detaljer

Författare
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Endokrinologi och diabetes
Originalspråkengelska
Sidor (från-till)146-154
TidskriftJournal of Clinical Investigation
Volym115
Utgivningsnummer1
StatusPublished - 2005
PublikationskategoriForskning
Peer review utfördJa

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Relaterad forskningsoutput

Xingjun Jing, 2007, Islet patophysiology. 108 s.

Forskningsoutput: AvhandlingDoktorsavhandling (sammanläggning)

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