Galanin evokes a cytosolic calcium bursting mode and hormone release in GH3/B6 pituitary cells.
The effects of galanin on secretion and cytosolic free Ca2+ concentration ([Ca2+]i) have been studied in GH3/B6 pituitary cells. Prolactin (PRL) and growth hormone (GH) release was measured in column perifusion experiments; [Ca2+]i was monitored in single cells by dual emission microspectrofluorimetry using indo-1 as intracellular Ca2+ probe. Galanin (0.1-1 nM) caused PRL and GH release coincident with a modest rise in [Ca2+]i. The increase in [Ca2+]i comprises the establishment of characteristic long-lasting bursts of [Ca2+]i transients. Galanin acts on Ca2+ entry through voltage-gated Ca2+ channels since there was no response to the peptide when Cd2(+)-a Ca2+ channel blocker-was added to the bath solution. The stimulation of bursting activity by galanin may provide a fine Ca2(+)-signalling mechanism which maximally stimulates hormone release while avoiding refractory periods.
Laboratory of Neurophysiology, CNRS URA 1200, University of Bordeaux II, France.
N
N
Guérineau
R
R
Drouhault
J B
JB
Corcuff
A M
AM
Vacher
N
N
Vilayleck
P
P
Mollard
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D019004:Galanin; D013006:Growth Hormone / Q000378:metabolism*; D007700:Kinetics; D009479:Neuropeptides / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D010911:Pituitary Neoplasms; D011388:Prolactin / Q000378:metabolism*
D009479:Neuropeptides; D010455:Peptides; D019004:Galanin; D011388:Prolactin; D013006:Growth Hormone; D002118:Calcium