Ahearn G. A.

Boyd D. B.

Flik G.

Greenaway P.

Jennifer R. Weil

Michele G. Wheatly

Nellans H. N.

Neufeld D. S.

Perry S. F.

Philipson K. D.

Robert C. Pence

Schoenmakers T.

Towle D. W.

Verbost P. M.

Wheatly M. G.

Zhuang Z.

ATP-dependent Ca2+uptake was determined into inside-out basolateral membrane vesicles (BLMV) from intermolt crayfish ( Procambarus clarkii) Ca2+-transporting epithelia: gill, hepatopancreas (liver), and antennal gland (kidney). Extravesicular (EV) ATP (5 mM) increased45Ca2+uptake (free Ca2+5 μM) by fivefold but was abolished by pretreatment with either vanadate or the ionophore A-23187. Addition of A-23187 to Ca2+-loaded vesicles produced 70% efflux. The saturable carrier exhibited a Kmfor Ca2+of 0.11–0.27 μM and maximal influx of 20–123 pmol ⋅ mg−1⋅ min−1. The Kmfor ATP was 0.01–0.04 mM. The temperature coefficient ranged from 1.43 to 2.06. EGTA treatment of hepatopancreas and antennal gland vesicles decreased45Ca2+uptake by 50–90%; uptake was restorable by calmodulin. However, in gill,45Ca2+uptake was unaffected by EGTA treatment and calmodulin decreased uptake in both EGTA-treated and untreated vesicles. Addition of EV Na+(5 mM) increased ATP-dependent Ca2+uptake into hepatopancreas and antennal gland BLMV by 60%; in hepatopancreas BLMV, this increase was inhibitable by ouabain. However, ATP-dependent Ca2+uptake in gill vesicles was Na+independent. The relative role of each epithelium in whole animal Ca2+homeostasis has been interpreted based on in vitro characteristics.</jats:p

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AJP Regulatory Integrative and Comparative Physiology

ATP-dependent calcium uptake into basolateral vesicles from transporting epithelia of intermolt crayfish

ATP-dependent calcium uptake into basolateral vesicles  from transporting epithelia of intermolt crayfish

ATP-dependent calcium uptake into basolateral vesicles from transporting epithelia of intermolt crayfish

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