[The demonstration of steady-state Ca2+ influx into the cells of the salivary glands in Chironomus plumosus L. larvae and its role in basal secretion].
Ca2+ content in Chironomus plumosus salivary gland tissue we determined using Ca(2+)-sensitive dye arsenazo III and protein concentration in medium--by Lowry method. It was showed correlation between increasing of Ca2+ content in gland and basal secretion. So, basal secretion is Ca(2+)-dependent process. Owing to adding to medium verapamil, diltiazem and nifedipine (10(-4) M) took place decreasing of Ca2+ content and secretion. Since decreasing of Ca2+ entry in cells owing to blocators action did't exceed 53% (in the case of nifedipine) we assumed that permanent Ca2+ entry formed by potential- and receptor-operated channels. It was established dependence of continuous Ca2+ entry in cells, basal secretion and effectiveness of blockade of Ca(2+)-channels by nifedipine on the [Ca2+]e. Therefore, through the exocrine secretory cells membrane of Chironomus plumosus larvae salivary gland carry out continuous diffuse Ca2+ entry for maintain of basal secretion by cells. This Ca2+ entry provide by population of open Ca(2+)-channels, sensitive to blocators of potential dependent of Ca(2+)-conduction plasmatic membrane.
Fedirko
N V
NV
I. Franko Medical University, L'viv.
Klevets'
M Iu
MIu
D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000032:analysis / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002683:Chironomidae / Q000187:drug effects / Q000502:physiology*; D004110:Diltiazem / Q000494:pharmacology; D066298:In Vitro Techniques; D007814:Larva / Q000187:drug effects / Q000502:physiology; D009543:Nifedipine / Q000494:pharmacology; D012469:Salivary Glands / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D012472:Salivation / Q000187:drug effects / Q000502:physiology*; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D014700:Verapamil; D004110:Diltiazem; D009543:Nifedipine; D002118:Calcium