Pharmacological characterization of the voltage-dependent calcium channel of pancreatic B-cell

Endocrinology. 1989 Oct;125(4):2008-14. doi: 10.1210/endo-125-4-2008.


Pharmacological characteristics of the voltage-dependent calcium channel (VDCC) of the pancreatic B-cell were studied using omega-conotoxin (omega CgTX) and dihydropyridine (DHP) calcium channel blockers. High glucose and potassium (K+) depolarization were employed as the stimulant of insulin release. omega CgTX (greater than 50 nM), a blocker of neural, but not muscular, Ca2+ channels, partially blocked (27%) the second, but not the first, phase of glucose-induced insulin release without a significant effect on K+ depolarization-induced insulin release. The DHP Ca2+ channel blocker nifedipine inhibited both phases of glucose-induced insulin release (ED50 = 200 nM) and completely abolished both phases of response at 10 microM. In contrast, the DHP Ca2+ channel blocker only partially suppressed (75% at 10 microM) K+ depolarization-induced insulin release with an ED50 of 100 nM. We conclude that pancreatic B-cell possesses at least two classes of VDCCs; one is DHP sensitive, and the other DHP insensitive. Partial suppression of the second phase of glucose-induced insulin release by a high concentration of omega CgTX may be due to its toxic effect on the secretory machinery other than VDCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / drug effects
  • Calcium Channels / metabolism*
  • Calcium Channels / physiology
  • Dihydropyridines / pharmacology
  • Electrophysiology
  • Glucose / pharmacology
  • Insulin / metabolism
  • Islets of Langerhans / metabolism*
  • Male
  • Mollusk Venoms / pharmacology
  • Nifedipine / pharmacology
  • Osmolar Concentration
  • Potassium / physiology
  • Potassium Chloride / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Time Factors
  • omega-Conotoxin GVIA


  • Calcium Channel Blockers
  • Calcium Channels
  • Dihydropyridines
  • Insulin
  • Mollusk Venoms
  • Potassium Chloride
  • 1,4-dihydropyridine
  • omega-Conotoxin GVIA
  • Nifedipine
  • Glucose
  • Potassium