par Plasman, P O;Hermann, Marcel 
;Herchuelz, André ;Lebrun, Philippe
Référence The American journal of physiology, 258, 3 Pt 1, page (E529-E533)
Publication Publié, 1990-03
;Herchuelz, André ;Lebrun, Philippe Référence The American journal of physiology, 258, 3 Pt 1, page (E529-E533)
Publication Publié, 1990-03
Article révisé par les pairs
| Résumé : | The presence of different types [long lasting (L) and transient (T)] of active voltage-operated Ca2+ channels in islet cells was investigated by comparing the effects of Cd2+, Ni2+, and 1,4-dihydropyridines on 45Ca uptake, 45Ca efflux, and insulin release in intact rat pancreatic islets. In several other excitable cells the L-channel has been shown to be modulated by 1,4-dihydropyridines and Cd2+, whereas the T-channel was reported to be sensitive to Ni2+. Nifedipine and Cd2+ inhibited whereas BAY K 8644 enhanced the glucose (11.1, 22.2 mM)-stimulated short-term 45Ca uptake, 45Ca efflux, and insulin release. In contrast, the stimulatory effects of glucose (11.1, 22.2 mM) on 45Ca uptake, 45Ca efflux, and insulin release were unaffected by Ni2+. These findings confirm that glucose provokes Ca2+ entry mainly by activating voltage-sensitive Ca2+ channels of the L-type and suggest that the B-cell plasma membrane is not equipped with active T-type Ca2+ channels. |
